Commit Graph

1178 Commits

Author SHA1 Message Date
Bijan Mottahedeh 2a63b2d9c3 io_uring: add rsrc_ref locking routines
Encapsulate resource reference locking into separate routines.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-01 10:02:42 -07:00
Bijan Mottahedeh d67d2263fb io_uring: separate ref_list from fixed_rsrc_data
Uplevel ref_list and make it common to all resources.  This is to
allow one common ref_list to be used for both files, and buffers
in upcoming patches.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-01 10:02:42 -07:00
Bijan Mottahedeh 5023853183 io_uring: generalize io_queue_rsrc_removal
Generalize io_queue_rsrc_removal to handle both files and buffers.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
[remove io_mapped_ubuf from rsrc tables/etc. for now]
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-01 10:02:41 -07:00
Bijan Mottahedeh 269bbe5fd4 io_uring: rename file related variables to rsrc
This is a prep rename patch for subsequent patches to generalize file
registration.

[io_uring_rsrc_update:: rename fds -> data]

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
[leave io_uring_files_update as struct]
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-01 10:02:41 -07:00
Bijan Mottahedeh 2b358604aa io_uring: modularize io_sqe_buffers_register
Move allocation of buffer management structures, and validation of
buffers into separate routines.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-01 10:02:41 -07:00
Bijan Mottahedeh 0a96bbe499 io_uring: modularize io_sqe_buffer_register
Split io_sqe_buffer_register into two routines:

- io_sqe_buffer_register() registers a single buffer
- io_sqe_buffers_register iterates over all user specified buffers

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-01 10:02:41 -07:00
Jens Axboe 3a81fd0204 io_uring: enable LOOKUP_CACHED path resolution for filename lookups
Instead of being pessimistic and assume that path lookup will block, use
LOOKUP_CACHED to attempt just a cached lookup. This ensures that the
fast path is always done inline, and we only punt to async context if
IO is needed to satisfy the lookup.

For forced nonblock open attempts, mark the file O_NONBLOCK over the
actual ->open() call as well. We can safely clear this again before
doing fd_install(), so it'll never be user visible that we fiddled with
it.

This greatly improves the performance of file open where the dentry is
already cached:

ached		5.10-git	5.10-git+LOOKUP_CACHED	Speedup
---------------------------------------------------------------
33%		1,014,975	900,474			1.1x
89%		 545,466	292,937			1.9x
100%		 435,636	151,475			2.9x

The more cache hot we are, the faster the inline LOOKUP_CACHED
optimization helps. This is unsurprising and expected, as a thread
offload becomes a more dominant part of the total overhead. If we look
at io_uring tracing, doing an IORING_OP_OPENAT on a file that isn't in
the dentry cache will yield:

275.550481: io_uring_create: ring 00000000ddda6278, fd 3 sq size 8, cq size 16, flags 0
275.550491: io_uring_submit_sqe: ring 00000000ddda6278, op 18, data 0x0, non block 1, sq_thread 0
275.550498: io_uring_queue_async_work: ring 00000000ddda6278, request 00000000c0267d17, flags 69760, normal queue, work 000000003d683991
275.550502: io_uring_cqring_wait: ring 00000000ddda6278, min_events 1
275.550556: io_uring_complete: ring 00000000ddda6278, user_data 0x0, result 4

which shows a failed nonblock lookup, then punt to worker, and then we
complete with fd == 4. This takes 65 usec in total. Re-running the same
test case again:

281.253956: io_uring_create: ring 0000000008207252, fd 3 sq size 8, cq size 16, flags 0
281.253967: io_uring_submit_sqe: ring 0000000008207252, op 18, data 0x0, non block 1, sq_thread 0
281.253973: io_uring_complete: ring 0000000008207252, user_data 0x0, result 4

shows the same request completing inline, also returning fd == 4. This
takes 6 usec.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-01 10:02:41 -07:00
Pavel Begunkov 3a7efd1ad2 io_uring: reinforce cancel on flush during exit
What 84965ff8a8 ("io_uring: if we see flush on exit, cancel related tasks")
really wants is to cancel all relevant REQ_F_INFLIGHT requests reliably.
That can be achieved by io_uring_cancel_files(), but we'll miss it
calling io_uring_cancel_task_requests(files=NULL) from io_uring_flush(),
because it will go through __io_uring_cancel_task_requests().

Just always call io_uring_cancel_files() during cancel, it's good enough
for now.

Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-28 17:04:24 -07:00
Pavel Begunkov 70b2c60d37 io_uring: fix sqo ownership false positive warning
WARNING: CPU: 0 PID: 21359 at fs/io_uring.c:9042
    io_uring_cancel_task_requests+0xe55/0x10c0 fs/io_uring.c:9042
Call Trace:
 io_uring_flush+0x47b/0x6e0 fs/io_uring.c:9227
 filp_close+0xb4/0x170 fs/open.c:1295
 close_files fs/file.c:403 [inline]
 put_files_struct fs/file.c:418 [inline]
 put_files_struct+0x1cc/0x350 fs/file.c:415
 exit_files+0x7e/0xa0 fs/file.c:435
 do_exit+0xc22/0x2ae0 kernel/exit.c:820
 do_group_exit+0x125/0x310 kernel/exit.c:922
 get_signal+0x427/0x20f0 kernel/signal.c:2773
 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:811
 handle_signal_work kernel/entry/common.c:147 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x148/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Now io_uring_cancel_task_requests() can be called not through file
notes but directly, remove a WARN_ONCE() there that give us false
positives. That check is not very important and we catch it in other
places.

Fixes: 84965ff8a8 ("io_uring: if we see flush on exit, cancel related tasks")
Cc: stable@vger.kernel.org # 5.9+
Reported-by: syzbot+3e3d9bd0c6ce9efbc3ef@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-28 11:44:13 -07:00
Pavel Begunkov f609cbb891 io_uring: fix list corruption for splice file_get
kernel BUG at lib/list_debug.c:29!
Call Trace:
 __list_add include/linux/list.h:67 [inline]
 list_add include/linux/list.h:86 [inline]
 io_file_get+0x8cc/0xdb0 fs/io_uring.c:6466
 __io_splice_prep+0x1bc/0x530 fs/io_uring.c:3866
 io_splice_prep fs/io_uring.c:3920 [inline]
 io_req_prep+0x3546/0x4e80 fs/io_uring.c:6081
 io_queue_sqe+0x609/0x10d0 fs/io_uring.c:6628
 io_submit_sqe fs/io_uring.c:6705 [inline]
 io_submit_sqes+0x1495/0x2720 fs/io_uring.c:6953
 __do_sys_io_uring_enter+0x107d/0x1f30 fs/io_uring.c:9353
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

io_file_get() may be called from splice, and so REQ_F_INFLIGHT may
already be set.

Fixes: 02a13674fa ("io_uring: account io_uring internal files as REQ_F_INFLIGHT")
Cc: stable@vger.kernel.org # 5.9+
Reported-by: syzbot+6879187cf57845801267@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-28 11:44:12 -07:00
Hao Xu 6195ba0982 io_uring: fix flush cqring overflow list while TASK_INTERRUPTIBLE
Abaci reported the follow warning:

[   27.073425] do not call blocking ops when !TASK_RUNNING; state=1 set at [] prepare_to_wait_exclusive+0x3a/0xc0
[   27.075805] WARNING: CPU: 0 PID: 951 at kernel/sched/core.c:7853 __might_sleep+0x80/0xa0
[   27.077604] Modules linked in:
[   27.078379] CPU: 0 PID: 951 Comm: a.out Not tainted 5.11.0-rc3+ #1
[   27.079637] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
[   27.080852] RIP: 0010:__might_sleep+0x80/0xa0
[   27.081835] Code: 65 48 8b 04 25 80 71 01 00 48 8b 90 c0 15 00 00 48 8b 70 18 48 c7 c7 08 39 95 82 c6 05 f9 5f de 08 01 48 89 d1 e8 00 c6 fa ff  0b eb bf 41 0f b6 f5 48 c7 c7 40 23 c9 82 e8 f3 48 ec 00 eb a7
[   27.084521] RSP: 0018:ffffc90000fe3ce8 EFLAGS: 00010286
[   27.085350] RAX: 0000000000000000 RBX: ffffffff82956083 RCX: 0000000000000000
[   27.086348] RDX: ffff8881057a0000 RSI: ffffffff8118cc9e RDI: ffff88813bc28570
[   27.087598] RBP: 00000000000003a7 R08: 0000000000000001 R09: 0000000000000001
[   27.088819] R10: ffffc90000fe3e00 R11: 00000000fffef9f0 R12: 0000000000000000
[   27.089819] R13: 0000000000000000 R14: ffff88810576eb80 R15: ffff88810576e800
[   27.091058] FS:  00007f7b144cf740(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
[   27.092775] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   27.093796] CR2: 00000000022da7b8 CR3: 000000010b928002 CR4: 00000000003706f0
[   27.094778] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   27.095780] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   27.097011] Call Trace:
[   27.097685]  __mutex_lock+0x5d/0xa30
[   27.098565]  ? prepare_to_wait_exclusive+0x71/0xc0
[   27.099412]  ? io_cqring_overflow_flush.part.101+0x6d/0x70
[   27.100441]  ? lockdep_hardirqs_on_prepare+0xe9/0x1c0
[   27.101537]  ? _raw_spin_unlock_irqrestore+0x2d/0x40
[   27.102656]  ? trace_hardirqs_on+0x46/0x110
[   27.103459]  ? io_cqring_overflow_flush.part.101+0x6d/0x70
[   27.104317]  io_cqring_overflow_flush.part.101+0x6d/0x70
[   27.105113]  io_cqring_wait+0x36e/0x4d0
[   27.105770]  ? find_held_lock+0x28/0xb0
[   27.106370]  ? io_uring_remove_task_files+0xa0/0xa0
[   27.107076]  __x64_sys_io_uring_enter+0x4fb/0x640
[   27.107801]  ? rcu_read_lock_sched_held+0x59/0xa0
[   27.108562]  ? lockdep_hardirqs_on_prepare+0xe9/0x1c0
[   27.109684]  ? syscall_enter_from_user_mode+0x26/0x70
[   27.110731]  do_syscall_64+0x2d/0x40
[   27.111296]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   27.112056] RIP: 0033:0x7f7b13dc8239
[   27.112663] Code: 01 00 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05  3d 01 f0 ff ff 73 01 c3 48 8b 0d 27 ec 2c 00 f7 d8 64 89 01 48
[   27.115113] RSP: 002b:00007ffd6d7f5c88 EFLAGS: 00000286 ORIG_RAX: 00000000000001aa
[   27.116562] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7b13dc8239
[   27.117961] RDX: 000000000000478e RSI: 0000000000000000 RDI: 0000000000000003
[   27.118925] RBP: 00007ffd6d7f5cb0 R08: 0000000020000040 R09: 0000000000000008
[   27.119773] R10: 0000000000000001 R11: 0000000000000286 R12: 0000000000400480
[   27.120614] R13: 00007ffd6d7f5d90 R14: 0000000000000000 R15: 0000000000000000
[   27.121490] irq event stamp: 5635
[   27.121946] hardirqs last  enabled at (5643): [] console_unlock+0x5c4/0x740
[   27.123476] hardirqs last disabled at (5652): [] console_unlock+0x4e7/0x740
[   27.125192] softirqs last  enabled at (5272): [] __do_softirq+0x3c5/0x5aa
[   27.126430] softirqs last disabled at (5267): [] asm_call_irq_on_stack+0xf/0x20
[   27.127634] ---[ end trace 289d7e28fa60f928 ]---

This is caused by calling io_cqring_overflow_flush() which may sleep
after calling prepare_to_wait_exclusive() which set task state to
TASK_INTERRUPTIBLE

Reported-by: Abaci <abaci@linux.alibaba.com>
Fixes: 6c503150ae ("io_uring: patch up IOPOLL overflow_flush sync")
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-27 09:18:28 -07:00
Pavel Begunkov 907d1df30a io_uring: fix wqe->lock/completion_lock deadlock
Joseph reports following deadlock:

CPU0:
...
io_kill_linked_timeout  // &ctx->completion_lock
io_commit_cqring
__io_queue_deferred
__io_queue_async_work
io_wq_enqueue
io_wqe_enqueue  // &wqe->lock

CPU1:
...
__io_uring_files_cancel
io_wq_cancel_cb
io_wqe_cancel_pending_work  // &wqe->lock
io_cancel_task_cb  // &ctx->completion_lock

Only __io_queue_deferred() calls queue_async_work() while holding
ctx->completion_lock, enqueue drained requests via io_req_task_queue()
instead.

Cc: stable@vger.kernel.org # 5.9+
Reported-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-26 19:36:55 -07:00
Pavel Begunkov ca70f00bed io_uring: fix cancellation taking mutex while TASK_UNINTERRUPTIBLE
do not call blocking ops when !TASK_RUNNING; state=2 set at
	[<00000000ced9dbfc>] prepare_to_wait+0x1f4/0x3b0
	kernel/sched/wait.c:262
WARNING: CPU: 1 PID: 19888 at kernel/sched/core.c:7853
	__might_sleep+0xed/0x100 kernel/sched/core.c:7848
RIP: 0010:__might_sleep+0xed/0x100 kernel/sched/core.c:7848
Call Trace:
 __mutex_lock_common+0xc4/0x2ef0 kernel/locking/mutex.c:935
 __mutex_lock kernel/locking/mutex.c:1103 [inline]
 mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:1118
 io_wq_submit_work+0x39a/0x720 fs/io_uring.c:6411
 io_run_cancel fs/io-wq.c:856 [inline]
 io_wqe_cancel_pending_work fs/io-wq.c:990 [inline]
 io_wq_cancel_cb+0x614/0xcb0 fs/io-wq.c:1027
 io_uring_cancel_files fs/io_uring.c:8874 [inline]
 io_uring_cancel_task_requests fs/io_uring.c:8952 [inline]
 __io_uring_files_cancel+0x115d/0x19e0 fs/io_uring.c:9038
 io_uring_files_cancel include/linux/io_uring.h:51 [inline]
 do_exit+0x2e6/0x2490 kernel/exit.c:780
 do_group_exit+0x168/0x2d0 kernel/exit.c:922
 get_signal+0x16b5/0x2030 kernel/signal.c:2770
 arch_do_signal_or_restart+0x8e/0x6a0 arch/x86/kernel/signal.c:811
 handle_signal_work kernel/entry/common.c:147 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0xac/0x1e0 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x48/0x190 kernel/entry/common.c:302
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Rewrite io_uring_cancel_files() to mimic __io_uring_task_cancel()'s
counting scheme, so it does all the heavy work before setting
TASK_UNINTERRUPTIBLE.

Cc: stable@vger.kernel.org # 5.9+
Reported-by: syzbot+f655445043a26a7cfab8@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: fix inverted task check]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-26 09:01:49 -07:00
Pavel Begunkov a1bb3cd589 io_uring: fix __io_uring_files_cancel() with TASK_UNINTERRUPTIBLE
If the tctx inflight number haven't changed because of cancellation,
__io_uring_task_cancel() will continue leaving the task in
TASK_UNINTERRUPTIBLE state, that's not expected by
__io_uring_files_cancel(). Ensure we always call finish_wait() before
retrying.

Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-26 08:51:08 -07:00
Jens Axboe b18032bb0a io_uring: only call io_cqring_ev_posted() if events were posted
This normally doesn't cause any extra harm, but it does mean that we'll
increment the eventfd notification count, if one has been registered
with the ring. This can confuse applications, when they see more
notifications on the eventfd side than are available in the ring.

Do the nice thing and only increment this count, if we actually posted
(or even overflowed) events.

Reported-and-tested-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-24 18:13:56 -07:00
Jens Axboe 84965ff8a8 io_uring: if we see flush on exit, cancel related tasks
Ensure we match tasks that belong to a dead or dying task as well, as we
need to reap those in addition to those belonging to the exiting task.

Cc: stable@vger.kernel.org # 5.9+
Reported-by: Josef Grieb <josef.grieb@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-24 18:13:56 -07:00
Jens Axboe 02a13674fa io_uring: account io_uring internal files as REQ_F_INFLIGHT
We need to actively cancel anything that introduces a potential circular
loop, where io_uring holds a reference to itself. If the file in question
is an io_uring file, then add the request to the inflight list.

Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-24 10:15:33 -07:00
Pavel Begunkov 9d5c819068 io_uring: fix sleeping under spin in __io_clean_op
[   27.629441] BUG: sleeping function called from invalid context
	at fs/file.c:402
[   27.631317] in_atomic(): 1, irqs_disabled(): 1, non_block: 0,
	pid: 1012, name: io_wqe_worker-0
[   27.633220] 1 lock held by io_wqe_worker-0/1012:
[   27.634286]  #0: ffff888105e26c98 (&ctx->completion_lock)
	{....}-{2:2}, at: __io_req_complete.part.102+0x30/0x70
[   27.649249] Call Trace:
[   27.649874]  dump_stack+0xac/0xe3
[   27.650666]  ___might_sleep+0x284/0x2c0
[   27.651566]  put_files_struct+0xb8/0x120
[   27.652481]  __io_clean_op+0x10c/0x2a0
[   27.653362]  __io_cqring_fill_event+0x2c1/0x350
[   27.654399]  __io_req_complete.part.102+0x41/0x70
[   27.655464]  io_openat2+0x151/0x300
[   27.656297]  io_issue_sqe+0x6c/0x14e0
[   27.660991]  io_wq_submit_work+0x7f/0x240
[   27.662890]  io_worker_handle_work+0x501/0x8a0
[   27.664836]  io_wqe_worker+0x158/0x520
[   27.667726]  kthread+0x134/0x180
[   27.669641]  ret_from_fork+0x1f/0x30

Instead of cleaning files on overflow, return back overflow cancellation
into io_uring_cancel_files(). Previously it was racy to clean
REQ_F_OVERFLOW flag, but we got rid of it, and can do it through
repetitive attempts targeting all matching requests.

Reported-by: Abaci <abaci@linux.alibaba.com>
Reported-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-24 10:15:33 -07:00
Pavel Begunkov 9a173346bd io_uring: fix short read retries for non-reg files
Sockets and other non-regular files may actually expect short reads to
happen, don't retry reads for them. Because non-reg files don't set
FMODE_BUF_RASYNC and so it won't do second/retry do_read, we can filter
out those cases after first do_read() attempt with ret>0.

Cc: stable@vger.kernel.org # 5.9+
Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-22 12:42:54 -07:00
Jens Axboe 607ec89ed1 io_uring: fix SQPOLL IORING_OP_CLOSE cancelation state
IORING_OP_CLOSE is special in terms of cancelation, since it has an
intermediate state where we've removed the file descriptor but hasn't
closed the file yet. For that reason, it's currently marked with
IO_WQ_WORK_NO_CANCEL to prevent cancelation. This ensures that the op
is always run even if canceled, to prevent leaving us with a live file
but an fd that is gone. However, with SQPOLL, since a cancel request
doesn't carry any resources on behalf of the request being canceled, if
we cancel before any of the close op has been run, we can end up with
io-wq not having the ->files assigned. This can result in the following
oops reported by Joseph:

BUG: kernel NULL pointer dereference, address: 00000000000000d8
PGD 800000010b76f067 P4D 800000010b76f067 PUD 10b462067 PMD 0
Oops: 0000 [#1] SMP PTI
CPU: 1 PID: 1788 Comm: io_uring-sq Not tainted 5.11.0-rc4 #1
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
RIP: 0010:__lock_acquire+0x19d/0x18c0
Code: 00 00 8b 1d fd 56 dd 08 85 db 0f 85 43 05 00 00 48 c7 c6 98 7b 95 82 48 c7 c7 57 96 93 82 e8 9a bc f5 ff 0f 0b e9 2b 05 00 00 <48> 81 3f c0 ca 67 8a b8 00 00 00 00 41 0f 45 c0 89 04 24 e9 81 fe
RSP: 0018:ffffc90001933828 EFLAGS: 00010002
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000000000d8
RBP: 0000000000000246 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff888106e8a140 R15: 00000000000000d8
FS:  0000000000000000(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000d8 CR3: 0000000106efa004 CR4: 00000000003706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 lock_acquire+0x31a/0x440
 ? close_fd_get_file+0x39/0x160
 ? __lock_acquire+0x647/0x18c0
 _raw_spin_lock+0x2c/0x40
 ? close_fd_get_file+0x39/0x160
 close_fd_get_file+0x39/0x160
 io_issue_sqe+0x1334/0x14e0
 ? lock_acquire+0x31a/0x440
 ? __io_free_req+0xcf/0x2e0
 ? __io_free_req+0x175/0x2e0
 ? find_held_lock+0x28/0xb0
 ? io_wq_submit_work+0x7f/0x240
 io_wq_submit_work+0x7f/0x240
 io_wq_cancel_cb+0x161/0x580
 ? io_wqe_wake_worker+0x114/0x360
 ? io_uring_get_socket+0x40/0x40
 io_async_find_and_cancel+0x3b/0x140
 io_issue_sqe+0xbe1/0x14e0
 ? __lock_acquire+0x647/0x18c0
 ? __io_queue_sqe+0x10b/0x5f0
 __io_queue_sqe+0x10b/0x5f0
 ? io_req_prep+0xdb/0x1150
 ? mark_held_locks+0x6d/0xb0
 ? mark_held_locks+0x6d/0xb0
 ? io_queue_sqe+0x235/0x4b0
 io_queue_sqe+0x235/0x4b0
 io_submit_sqes+0xd7e/0x12a0
 ? _raw_spin_unlock_irq+0x24/0x30
 ? io_sq_thread+0x3ae/0x940
 io_sq_thread+0x207/0x940
 ? do_wait_intr_irq+0xc0/0xc0
 ? __ia32_sys_io_uring_enter+0x650/0x650
 kthread+0x134/0x180
 ? kthread_create_worker_on_cpu+0x90/0x90
 ret_from_fork+0x1f/0x30

Fix this by moving the IO_WQ_WORK_NO_CANCEL until _after_ we've modified
the fdtable. Canceling before this point is totally fine, and running
it in the io-wq context _after_ that point is also fine.

For 5.12, we'll handle this internally and get rid of the no-cancel
flag, as IORING_OP_CLOSE is the only user of it.

Cc: stable@vger.kernel.org
Fixes: b5dba59e0c ("io_uring: add support for IORING_OP_CLOSE")
Reported-by: "Abaci <abaci@linux.alibaba.com>"
Reviewed-and-tested-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-22 12:42:54 -07:00
Pavel Begunkov 0b5cd6c32b io_uring: fix skipping disabling sqo on exec
If there are no requests at the time __io_uring_task_cancel() is called,
tctx_inflight() returns zero and and it terminates not getting a chance
to go through __io_uring_files_cancel() and do
io_disable_sqo_submit(). And we absolutely want them disabled by the
time cancellation ends.

Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Fixes: d9d05217cb ("io_uring: stop SQPOLL submit on creator's death")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-16 21:02:49 -07:00
Pavel Begunkov 4325cb498c io_uring: fix uring_flush in exit_files() warning
WARNING: CPU: 1 PID: 11100 at fs/io_uring.c:9096
	io_uring_flush+0x326/0x3a0 fs/io_uring.c:9096
RIP: 0010:io_uring_flush+0x326/0x3a0 fs/io_uring.c:9096
Call Trace:
 filp_close+0xb4/0x170 fs/open.c:1280
 close_files fs/file.c:401 [inline]
 put_files_struct fs/file.c:416 [inline]
 put_files_struct+0x1cc/0x350 fs/file.c:413
 exit_files+0x7e/0xa0 fs/file.c:433
 do_exit+0xc22/0x2ae0 kernel/exit.c:820
 do_group_exit+0x125/0x310 kernel/exit.c:922
 get_signal+0x3e9/0x20a0 kernel/signal.c:2770
 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:811
 handle_signal_work kernel/entry/common.c:147 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x148/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

An SQPOLL ring creator task may have gotten rid of its file note during
exit and called io_disable_sqo_submit(), but the io_uring is still left
referenced through fdtable, which will be put during close_files() and
cause a false positive warning.

First split the warning into two for more clarity when is hit, and the
add sqo_dead check to handle the described case.

Reported-by: syzbot+a32b546d58dde07875a1@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-16 12:14:02 -07:00
Pavel Begunkov 6b393a1ff1 io_uring: fix false positive sqo warning on flush
WARNING: CPU: 1 PID: 9094 at fs/io_uring.c:8884
	io_disable_sqo_submit+0x106/0x130 fs/io_uring.c:8884
Call Trace:
 io_uring_flush+0x28b/0x3a0 fs/io_uring.c:9099
 filp_close+0xb4/0x170 fs/open.c:1280
 close_fd+0x5c/0x80 fs/file.c:626
 __do_sys_close fs/open.c:1299 [inline]
 __se_sys_close fs/open.c:1297 [inline]
 __x64_sys_close+0x2f/0xa0 fs/open.c:1297
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

io_uring's final close() may be triggered by any task not only the
creator. It's well handled by io_uring_flush() including SQPOLL case,
though a warning in io_disable_sqo_submit() will fallaciously fire by
moving this warning out to the only call site that matters.

Reported-by: syzbot+2f5d1785dc624932da78@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-16 12:14:02 -07:00
Jens Axboe c93cc9e16d io_uring: iopoll requests should also wake task ->in_idle state
If we're freeing/finishing iopoll requests, ensure we check if the task
is in idling in terms of cancelation. Otherwise we could end up waiting
forever in __io_uring_task_cancel() if the task has active iopoll
requests that need cancelation.

Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-16 12:13:59 -07:00
Jens Axboe a8d13dbccb io_uring: ensure finish_wait() is always called in __io_uring_task_cancel()
If we enter with requests pending and performm cancelations, we'll have
a different inflight count before and after calling prepare_to_wait().
This causes the loop to restart. If we actually ended up canceling
everything, or everything completed in-between, then we'll break out
of the loop without calling finish_wait() on the waitqueue. This can
trigger a warning on exit_signals(), as we leave the task state in
TASK_UNINTERRUPTIBLE.

Put a finish_wait() after the loop to catch that case.

Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-15 16:04:23 -07:00
Marcelo Diop-Gonzalez f010505b78 io_uring: flush timeouts that should already have expired
Right now io_flush_timeouts() checks if the current number of events
is equal to ->timeout.target_seq, but this will miss some timeouts if
there have been more than 1 event added since the last time they were
flushed (possible in io_submit_flush_completions(), for example). Fix
it by recording the last sequence at which timeouts were flushed so
that the number of events seen can be compared to the number of events
needed without overflow.

Signed-off-by: Marcelo Diop-Gonzalez <marcelo827@gmail.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-15 10:02:28 -07:00
Pavel Begunkov 06585c497b io_uring: do sqo disable on install_fd error
WARNING: CPU: 0 PID: 8494 at fs/io_uring.c:8717
	io_ring_ctx_wait_and_kill+0x4f2/0x600 fs/io_uring.c:8717
Call Trace:
 io_uring_release+0x3e/0x50 fs/io_uring.c:8759
 __fput+0x283/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x190 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

failed io_uring_install_fd() is a special case, we don't do
io_ring_ctx_wait_and_kill() directly but defer it to fput, though still
need to io_disable_sqo_submit() before.

note: it doesn't fix any real problem, just a warning. That's because
sqring won't be available to the userspace in this case and so SQPOLL
won't submit anything.

Reported-by: syzbot+9c9c35374c0ecac06516@syzkaller.appspotmail.com
Fixes: d9d05217cb ("io_uring: stop SQPOLL submit on creator's death")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-13 08:29:17 -07:00
Pavel Begunkov b4411616c2 io_uring: fix null-deref in io_disable_sqo_submit
general protection fault, probably for non-canonical address
	0xdffffc0000000022: 0000 [#1] KASAN: null-ptr-deref
	in range [0x0000000000000110-0x0000000000000117]
RIP: 0010:io_ring_set_wakeup_flag fs/io_uring.c:6929 [inline]
RIP: 0010:io_disable_sqo_submit+0xdb/0x130 fs/io_uring.c:8891
Call Trace:
 io_uring_create fs/io_uring.c:9711 [inline]
 io_uring_setup+0x12b1/0x38e0 fs/io_uring.c:9739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

io_disable_sqo_submit() might be called before user rings were
allocated, don't do io_ring_set_wakeup_flag() in those cases.

Reported-by: syzbot+ab412638aeb652ded540@syzkaller.appspotmail.com
Fixes: d9d05217cb ("io_uring: stop SQPOLL submit on creator's death")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-13 08:29:17 -07:00
Pavel Begunkov 621fadc223 io_uring: don't take files/mm for a dead task
In rare cases a task may be exiting while io_ring_exit_work() trying to
cancel/wait its requests. It's ok for __io_sq_thread_acquire_mm()
because of SQPOLL check, but is not for __io_sq_thread_acquire_files().
Play safe and fail for both of them.

Cc: stable@vger.kernel.org # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-11 07:39:54 -07:00
Pavel Begunkov d434ab6db5 io_uring: drop mm and files after task_work_run
__io_req_task_submit() run by task_work can set mm and files, but
io_sq_thread() in some cases, and because __io_sq_thread_acquire_mm()
and __io_sq_thread_acquire_files() do a simple current->mm/files check
it may end up submitting IO with mm/files of another task.

We also need to drop it after in the end to drop potentially grabbed
references to them.

Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-11 07:39:54 -07:00
Pavel Begunkov d9d05217cb io_uring: stop SQPOLL submit on creator's death
When the creator of SQPOLL io_uring dies (i.e. sqo_task), we don't want
its internals like ->files and ->mm to be poked by the SQPOLL task, it
have never been nice and recently got racy. That can happen when the
owner undergoes destruction and SQPOLL tasks tries to submit new
requests in parallel, and so calls io_sq_thread_acquire*().

That patch halts SQPOLL submissions when sqo_task dies by introducing
sqo_dead flag. Once set, the SQPOLL task must not do any submission,
which is synchronised by uring_lock as well as the new flag.

The tricky part is to make sure that disabling always happens, that
means either the ring is discovered by creator's do_exit() -> cancel,
or if the final close() happens before it's done by the creator. The
last is guaranteed by the fact that for SQPOLL the creator task and only
it holds exactly one file note, so either it pins up to do_exit() or
removed by the creator on the final put in flush. (see comments in
uring_flush() around file->f_count == 2).

One more place that can trigger io_sq_thread_acquire_*() is
__io_req_task_submit(). Shoot off requests on sqo_dead there, even
though actually we don't need to. That's because cancellation of
sqo_task should wait for the request before going any further.

note 1: io_disable_sqo_submit() does io_ring_set_wakeup_flag() so the
caller would enter the ring to get an error, but it still doesn't
guarantee that the flag won't be cleared.

note 2: if final __userspace__ close happens not from the creator
task, the file note will pin the ring until the task dies.

Fixed: b1b6b5a30d ("kernel/io_uring: cancel io_uring before task works")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-09 09:21:43 -07:00
Pavel Begunkov 6b5733eb63 io_uring: add warn_once for io_uring_flush()
files_cancel() should cancel all relevant requests and drop file notes,
so we should never have file notes after that, including on-exit fput
and flush. Add a WARN_ONCE to be sure.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-09 09:21:43 -07:00
Pavel Begunkov 4f793dc40b io_uring: inline io_uring_attempt_task_drop()
A simple preparation change inlining io_uring_attempt_task_drop() into
io_uring_flush().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-09 09:21:43 -07:00
Pavel Begunkov 55e6ac1e1f io_uring: io_rw_reissue lockdep annotations
We expect io_rw_reissue() to take place only during submission with
uring_lock held. Add a lockdep annotation to check that invariant.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-09 09:21:43 -07:00
Pavel Begunkov b1445e59cc io_uring: synchronise ev_posted() with waitqueues
waitqueue_active() needs smp_mb() to be in sync with waitqueues
modification, but we miss it in io_cqring_ev_posted*() apart from
cq_wait() case.

Take an smb_mb() out of wq_has_sleeper() making it waitqueue_active(),
and place it a few lines before, so it can synchronise other
waitqueue_active() as well.

The patch doesn't add any additional overhead, so even if there are
no problems currently, it's just safer to have it this way.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-07 07:48:09 -07:00
Pavel Begunkov 4aa84f2ffa io_uring: dont kill fasync under completion_lock
CPU0                    CPU1
       ----                    ----
  lock(&new->fa_lock);
                               local_irq_disable();
                               lock(&ctx->completion_lock);
                               lock(&new->fa_lock);
  <Interrupt>
    lock(&ctx->completion_lock);

 *** DEADLOCK ***

Move kill_fasync() out of io_commit_cqring() to io_cqring_ev_posted(),
so it doesn't hold completion_lock while doing it. That saves from the
reported deadlock, and it's just nice to shorten the locking time and
untangle nested locks (compl_lock -> wq_head::lock).

Reported-by: syzbot+91ca3f25bd7f795f019c@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-07 07:48:09 -07:00
Pavel Begunkov 80c18e4ac2 io_uring: trigger eventfd for IOPOLL
Make sure io_iopoll_complete() tries to wake up eventfd, which currently
is skipped together with io_cqring_ev_posted() for non-SQPOLL IOPOLL.

Add an iopoll version of io_cqring_ev_posted(), duplicates a bit of
code, but they actually use different sets of wait queues may be for
better.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-07 07:48:09 -07:00
Matthew Wilcox (Oracle) 3e2224c586 io_uring: Fix return value from alloc_fixed_file_ref_node
alloc_fixed_file_ref_node() currently returns an ERR_PTR on failure.
io_sqe_files_unregister() expects it to return NULL and since it can only
return -ENOMEM, it makes more sense to change alloc_fixed_file_ref_node()
to behave that way.

Fixes: 1ffc54220c ("io_uring: fix io_sqe_files_unregister() hangs")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-06 09:19:49 -07:00
Ye Bin 170b3bbda0 io_uring: Delete useless variable ‘id’ in io_prep_async_work
Fix follow warning:
fs/io_uring.c:1523:22: warning: variable ‘id’ set but not used
[-Wunused-but-set-variable]
  struct io_identity *id;
                        ^~
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-05 11:34:23 -07:00
Pavel Begunkov 90df08538c io_uring: cancel more aggressively in exit_work
While io_ring_exit_work() is running new requests of all sorts may be
issued, so it should do a bit more to cancel them, otherwise they may
just get stuck. e.g. in io-wq, in poll lists, etc.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-04 15:22:51 -07:00
Pavel Begunkov de7f1d9e99 io_uring: drop file refs after task cancel
io_uring fds marked O_CLOEXEC and we explicitly cancel all requests
before going through exec, so we don't want to leave task's file
references to not our anymore io_uring instances.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-04 15:22:50 -07:00
Pavel Begunkov 6c503150ae io_uring: patch up IOPOLL overflow_flush sync
IOPOLL skips completion locking but keeps it under uring_lock, thus
io_cqring_overflow_flush() and so io_cqring_events() need additional
locking with uring_lock in some cases for IOPOLL.

Remove __io_cqring_overflow_flush() from io_cqring_events(), introduce a
wrapper around flush doing needed synchronisation and call it by hand.

Cc: stable@vger.kernel.org # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-04 15:22:29 -07:00
Pavel Begunkov 81b6d05cca io_uring: synchronise IOPOLL on task_submit fail
io_req_task_submit() might be called for IOPOLL, do the fail path under
uring_lock to comply with IOPOLL synchronisation based solely on it.

Cc: stable@vger.kernel.org # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-04 15:22:27 -07:00
Pavel Begunkov 1ffc54220c io_uring: fix io_sqe_files_unregister() hangs
io_sqe_files_unregister() uninterruptibly waits for enqueued ref nodes,
however requests keeping them may never complete, e.g. because of some
userspace dependency. Make sure it's interruptible otherwise it would
hang forever.

Cc: stable@vger.kernel.org # 5.6+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-30 19:35:53 -07:00
Pavel Begunkov 1642b4450d io_uring: add a helper for setting a ref node
Setting a new reference node to a file data is not trivial, don't repeat
it, add and use a helper.

Cc: stable@vger.kernel.org # 5.6+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-30 19:35:53 -07:00
Jens Axboe 77788775c7 io_uring: don't assume mm is constant across submits
If we COW the identity, we assume that ->mm never changes. But this
isn't true of multiple processes end up sharing the ring. Hence treat
id->mm like like any other process compontent when it comes to the
identity mapping. This is pretty trivial, just moving the existing grab
into io_grab_identity(), and including a check for the match.

Cc: stable@vger.kernel.org # 5.10
Fixes: 1e6fa5216a ("io_uring: COW io_identity on mismatch")
Reported-by: Christian Brauner <christian.brauner@ubuntu.com>:
Tested-by: Christian Brauner <christian.brauner@ubuntu.com>:
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-29 11:00:36 -07:00
Xiaoguang Wang c07e671951 io_uring: hold uring_lock while completing failed polled io in io_wq_submit_work()
io_iopoll_complete() does not hold completion_lock to complete polled io,
so in io_wq_submit_work(), we can not call io_req_complete() directly, to
complete polled io, otherwise there maybe concurrent access to cqring,
defer_list, etc, which is not safe. Commit dad1b1242f ("io_uring: always
let io_iopoll_complete() complete polled io") has fixed this issue, but
Pavel reported that IOPOLL apart from rw can do buf reg/unreg requests(
IORING_OP_PROVIDE_BUFFERS or IORING_OP_REMOVE_BUFFERS), so the fix is not
good.

Given that io_iopoll_complete() is always called under uring_lock, so here
for polled io, we can also get uring_lock to fix this issue.

Fixes: dad1b1242f ("io_uring: always let io_iopoll_complete() complete polled io")
Cc: <stable@vger.kernel.org> # 5.5+
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: don't deref 'req' after completing it']
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-22 17:14:53 -07:00
Pavel Begunkov 9faadcc8ab io_uring: fix double io_uring free
Once we created a file for current context during setup, we should not
call io_ring_ctx_wait_and_kill() directly as it'll be done by fput(file)

Cc: stable@vger.kernel.org # 5.10
Reported-by: syzbot+c9937dfb2303a5f18640@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: fix unused 'ret' for !CONFIG_UNIX]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-22 17:14:50 -07:00
Pavel Begunkov a528b04ea4 io_uring: fix ignoring xa_store errors
xa_store() may fail, check the result.

Cc: stable@vger.kernel.org # 5.10
Fixes: 0f2122045b ("io_uring: don't rely on weak ->files references")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-21 13:01:10 -07:00
Pavel Begunkov f57555eda9 io_uring: end waiting before task cancel attempts
Get rid of TASK_UNINTERRUPTIBLE and waiting with finish_wait before
going for next iteration in __io_uring_task_cancel(), because
__io_uring_files_cancel() doesn't expect that sheduling is disallowed.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-20 11:05:39 -07:00
Pavel Begunkov 55583d72e2 io_uring: always progress task_work on task cancel
Might happen that __io_uring_cancel_task_requests() cancels nothing but
there are task_works pending. We need to always run them.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-20 11:05:39 -07:00
Jens Axboe 00c18640c2 io_uring: make ctx cancel on exit targeted to actual ctx
Before IORING_SETUP_ATTACH_WQ, we could just cancel everything on the
io-wq when exiting. But that's not the case if they are shared, so
cancel for the specific ctx instead.

Cc: stable@vger.kernel.org
Fixes: 24369c2e3b ("io_uring: add io-wq workqueue sharing")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-20 10:45:02 -07:00
Pavel Begunkov dd20166236 io_uring: fix 0-iov read buffer select
Doing vectored buf-select read with 0 iovec passed is meaningless and
utterly broken, forbid it.

Cc: <stable@vger.kernel.org> # 5.7+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-19 06:26:56 -07:00
Pavel Begunkov dfea9fce29 io_uring: close a small race gap for files cancel
The purpose of io_uring_cancel_files() is to wait for all requests
matching ->files to go/be cancelled. We should first drop files of a
request in io_req_drop_files() and only then make it undiscoverable for
io_uring_cancel_files.

First drop, then delete from list. It's ok to leave req->id->files
dangling, because it's not dereferenced by cancellation code, only
compared against. It would potentially go to sleep and be awaken by
following in io_req_drop_files() wake_up().

Fixes: 0f2122045b ("io_uring: don't rely on weak ->files references")
Cc: <stable@vger.kernel.org> # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-18 08:16:02 -07:00
Pavel Begunkov 89448c47b8 io_uring: limit {io|sq}poll submit locking scope
We don't need to take uring_lock for SQPOLL|IOPOLL to do
io_cqring_overflow_flush() when cq_overflow_list is empty, remove it
from the hot path.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-17 08:40:52 -07:00
Pavel Begunkov 09e88404f4 io_uring: inline io_cqring_mark_overflow()
There is only one user of it and the name is misleading, get rid of it
by inlining. By the way make overflow_flush's return value deduction
simpler.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-17 08:40:52 -07:00
Pavel Begunkov e23de15fdb io_uring: consolidate CQ nr events calculation
Add a helper which calculates number of events in CQ. Handcoded version
of it in io_cqring_overflow_flush() is not the clearest thing, so it
makes it slightly more readable.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-17 08:40:52 -07:00
Pavel Begunkov 9cd2be519d io_uring: remove racy overflow list fast checks
list_empty_careful() is not racy only if some conditions are met, i.e.
no re-adds after del_init. io_cqring_overflow_flush() does list_move(),
so it's actually racy.

Remove those checks, we have ->cq_check_overflow for the fast path.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-17 08:40:52 -07:00
Pavel Begunkov cda286f071 io_uring: cancel reqs shouldn't kill overflow list
io_uring_cancel_task_requests() doesn't imply that the ring is going
away, it may continue to work well after that. The problem is that it
sets ->cq_overflow_flushed effectively disabling the CQ overflow feature

Split setting cq_overflow_flushed from flush, and do the first one only
on exit. It's ok in terms of cancellations because there is a
io_uring->in_idle check in __io_cqring_fill_event().

It also fixes a race with setting ->cq_overflow_flushed in
io_uring_cancel_task_requests, whuch's is not atomic and a part of a
bitmask with other flags. Though, the only other flag that's not set
during init is drain_next, so it's not as bad for sane architectures.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Fixes: 0f2122045b ("io_uring: don't rely on weak ->files references")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-17 08:40:45 -07:00
Jens Axboe 4bc4a91253 io_uring: hold mmap_sem for mm->locked_vm manipulation
The kernel doesn't seem to have clear rules around this, but various
spots are using the mmap_sem to serialize access to modifying the
locked_vm count. Play it safe and lock the mm for write when accounting
or unaccounting locked memory.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-17 07:53:33 -07:00
Jens Axboe a146468d76 io_uring: break links on shutdown failure
Ensure that the return value of __sys_shutdown_sock() is used to
potentially break links to the request, if we fail.

Fixes: 36f4fa6886 ("io_uring: add support for shutdown(2)")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-16 14:56:36 -07:00
Linus Torvalds ac7ac4618c for-5.11/block-2020-12-14
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Merge tag 'for-5.11/block-2020-12-14' of git://git.kernel.dk/linux-block

Pull block updates from Jens Axboe:
 "Another series of killing more code than what is being added, again
  thanks to Christoph's relentless cleanups and tech debt tackling.

  This contains:

   - blk-iocost improvements (Baolin Wang)

   - part0 iostat fix (Jeffle Xu)

   - Disable iopoll for split bios (Jeffle Xu)

   - block tracepoint cleanups (Christoph Hellwig)

   - Merging of struct block_device and hd_struct (Christoph Hellwig)

   - Rework/cleanup of how block device sizes are updated (Christoph
     Hellwig)

   - Simplification of gendisk lookup and removal of block device
     aliasing (Christoph Hellwig)

   - Block device ioctl cleanups (Christoph Hellwig)

   - Removal of bdget()/blkdev_get() as exported API (Christoph Hellwig)

   - Disk change rework, avoid ->revalidate_disk() (Christoph Hellwig)

   - sbitmap improvements (Pavel Begunkov)

   - Hybrid polling fix (Pavel Begunkov)

   - bvec iteration improvements (Pavel Begunkov)

   - Zone revalidation fixes (Damien Le Moal)

   - blk-throttle limit fix (Yu Kuai)

   - Various little fixes"

* tag 'for-5.11/block-2020-12-14' of git://git.kernel.dk/linux-block: (126 commits)
  blk-mq: fix msec comment from micro to milli seconds
  blk-mq: update arg in comment of blk_mq_map_queue
  blk-mq: add helper allocating tagset->tags
  Revert "block: Fix a lockdep complaint triggered by request queue flushing"
  nvme-loop: use blk_mq_hctx_set_fq_lock_class to set loop's lock class
  blk-mq: add new API of blk_mq_hctx_set_fq_lock_class
  block: disable iopoll for split bio
  block: Improve blk_revalidate_disk_zones() checks
  sbitmap: simplify wrap check
  sbitmap: replace CAS with atomic and
  sbitmap: remove swap_lock
  sbitmap: optimise sbitmap_deferred_clear()
  blk-mq: skip hybrid polling if iopoll doesn't spin
  blk-iocost: Factor out the base vrate change into a separate function
  blk-iocost: Factor out the active iocgs' state check into a separate function
  blk-iocost: Move the usage ratio calculation to the correct place
  blk-iocost: Remove unnecessary advance declaration
  blk-iocost: Fix some typos in comments
  blktrace: fix up a kerneldoc comment
  block: remove the request_queue to argument request based tracepoints
  ...
2020-12-16 12:57:51 -08:00
Linus Torvalds 48aba79bcf for-5.11/io_uring-2020-12-14
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Merge tag 'for-5.11/io_uring-2020-12-14' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:
 "Fairly light set of changes this time around, and mostly some bits
  that were pushed out to 5.11 instead of 5.10, fixes/cleanups, and a
  few features. In particular:

   - Cleanups around iovec import (David Laight, Pavel)

   - Add timeout support for io_uring_enter(2), which enables us to
     clean up liburing and avoid a timeout sqe submission in the
     completion path.

     The big win here is that it allows setups that split SQ and CQ
     handling into separate threads to avoid locking, as the CQ side
     will no longer submit when timeouts are needed when waiting for
     events (Hao Xu)

   - Add support for socket shutdown, and renameat/unlinkat.

   - SQPOLL cleanups and improvements (Xiaoguang Wang)

   - Allow SQPOLL setups for CAP_SYS_NICE, and enable regular
     (non-fixed) files to be used.

   - Cancelation improvements (Pavel)

   - Fixed file reference improvements (Pavel)

   - IOPOLL related race fixes (Pavel)

   - Lots of other little fixes and cleanups (mostly Pavel)"

* tag 'for-5.11/io_uring-2020-12-14' of git://git.kernel.dk/linux-block: (43 commits)
  io_uring: fix io_cqring_events()'s noflush
  io_uring: fix racy IOPOLL flush overflow
  io_uring: fix racy IOPOLL completions
  io_uring: always let io_iopoll_complete() complete polled io
  io_uring: add timeout update
  io_uring: restructure io_timeout_cancel()
  io_uring: fix files cancellation
  io_uring: use bottom half safe lock for fixed file data
  io_uring: fix miscounting ios_left
  io_uring: change submit file state invariant
  io_uring: check kthread stopped flag when sq thread is unparked
  io_uring: share fixed_file_refs b/w multiple rsrcs
  io_uring: replace inflight_wait with tctx->wait
  io_uring: don't take fs for recvmsg/sendmsg
  io_uring: only wake up sq thread while current task is in io worker context
  io_uring: don't acquire uring_lock twice
  io_uring: initialize 'timeout' properly in io_sq_thread()
  io_uring: refactor io_sq_thread() handling
  io_uring: always batch cancel in *cancel_files()
  io_uring: pass files into kill timeouts/poll
  ...
2020-12-16 12:44:05 -08:00
Linus Torvalds 005b2a9dc8 tif-task_work.arch-2020-12-14
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Merge tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block

Pull TIF_NOTIFY_SIGNAL updates from Jens Axboe:
 "This sits on top of of the core entry/exit and x86 entry branch from
  the tip tree, which contains the generic and x86 parts of this work.

  Here we convert the rest of the archs to support TIF_NOTIFY_SIGNAL.

  With that done, we can get rid of JOBCTL_TASK_WORK from task_work and
  signal.c, and also remove a deadlock work-around in io_uring around
  knowing that signal based task_work waking is invoked with the sighand
  wait queue head lock.

  The motivation for this work is to decouple signal notify based
  task_work, of which io_uring is a heavy user of, from sighand. The
  sighand lock becomes a huge contention point, particularly for
  threaded workloads where it's shared between threads. Even outside of
  threaded applications it's slower than it needs to be.

  Roman Gershman <romger@amazon.com> reported that his networked
  workload dropped from 1.6M QPS at 80% CPU to 1.0M QPS at 100% CPU
  after io_uring was changed to use TIF_NOTIFY_SIGNAL. The time was all
  spent hammering on the sighand lock, showing 57% of the CPU time there
  [1].

  There are further cleanups possible on top of this. One example is
  TIF_PATCH_PENDING, where a patch already exists to use
  TIF_NOTIFY_SIGNAL instead. Hopefully this will also lead to more
  consolidation, but the work stands on its own as well"

[1] https://github.com/axboe/liburing/issues/215

* tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block: (28 commits)
  io_uring: remove 'twa_signal_ok' deadlock work-around
  kernel: remove checking for TIF_NOTIFY_SIGNAL
  signal: kill JOBCTL_TASK_WORK
  io_uring: JOBCTL_TASK_WORK is no longer used by task_work
  task_work: remove legacy TWA_SIGNAL path
  sparc: add support for TIF_NOTIFY_SIGNAL
  riscv: add support for TIF_NOTIFY_SIGNAL
  nds32: add support for TIF_NOTIFY_SIGNAL
  ia64: add support for TIF_NOTIFY_SIGNAL
  h8300: add support for TIF_NOTIFY_SIGNAL
  c6x: add support for TIF_NOTIFY_SIGNAL
  alpha: add support for TIF_NOTIFY_SIGNAL
  xtensa: add support for TIF_NOTIFY_SIGNAL
  arm: add support for TIF_NOTIFY_SIGNAL
  microblaze: add support for TIF_NOTIFY_SIGNAL
  hexagon: add support for TIF_NOTIFY_SIGNAL
  csky: add support for TIF_NOTIFY_SIGNAL
  openrisc: add support for TIF_NOTIFY_SIGNAL
  sh: add support for TIF_NOTIFY_SIGNAL
  um: add support for TIF_NOTIFY_SIGNAL
  ...
2020-12-16 12:33:35 -08:00
Linus Torvalds faf145d6f3 Merge branch 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull execve updates from Eric Biederman:
 "This set of changes ultimately fixes the interaction of posix file
  lock and exec. Fundamentally most of the change is just moving where
  unshare_files is called during exec, and tweaking the users of
  files_struct so that the count of files_struct is not unnecessarily
  played with.

  Along the way fcheck and related helpers were renamed to more
  accurately reflect what they do.

  There were also many other small changes that fell out, as this is the
  first time in a long time much of this code has been touched.

  Benchmarks haven't turned up any practical issues but Al Viro has
  observed a possibility for a lot of pounding on task_lock. So I have
  some changes in progress to convert put_files_struct to always rcu
  free files_struct. That wasn't ready for the merge window so that will
  have to wait until next time"

* 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits)
  exec: Move io_uring_task_cancel after the point of no return
  coredump: Document coredump code exclusively used by cell spufs
  file: Remove get_files_struct
  file: Rename __close_fd_get_file close_fd_get_file
  file: Replace ksys_close with close_fd
  file: Rename __close_fd to close_fd and remove the files parameter
  file: Merge __alloc_fd into alloc_fd
  file: In f_dupfd read RLIMIT_NOFILE once.
  file: Merge __fd_install into fd_install
  proc/fd: In fdinfo seq_show don't use get_files_struct
  bpf/task_iter: In task_file_seq_get_next use task_lookup_next_fd_rcu
  proc/fd: In proc_readfd_common use task_lookup_next_fd_rcu
  file: Implement task_lookup_next_fd_rcu
  kcmp: In get_file_raw_ptr use task_lookup_fd_rcu
  proc/fd: In tid_fd_mode use task_lookup_fd_rcu
  file: Implement task_lookup_fd_rcu
  file: Rename fcheck lookup_fd_rcu
  file: Replace fcheck_files with files_lookup_fd_rcu
  file: Factor files_lookup_fd_locked out of fcheck_files
  file: Rename __fcheck_files to files_lookup_fd_raw
  ...
2020-12-15 19:29:43 -08:00
Linus Torvalds d635a69dd4 Networking updates for 5.11
Core:
 
  - support "prefer busy polling" NAPI operation mode, where we defer softirq
    for some time expecting applications to periodically busy poll
 
  - AF_XDP: improve efficiency by more batching and hindering
            the adjacency cache prefetcher
 
  - af_packet: make packet_fanout.arr size configurable up to 64K
 
  - tcp: optimize TCP zero copy receive in presence of partial or unaligned
         reads making zero copy a performance win for much smaller messages
 
  - XDP: add bulk APIs for returning / freeing frames
 
  - sched: support fragmenting IP packets as they come out of conntrack
 
  - net: allow virtual netdevs to forward UDP L4 and fraglist GSO skbs
 
 BPF:
 
  - BPF switch from crude rlimit-based to memcg-based memory accounting
 
  - BPF type format information for kernel modules and related tracing
    enhancements
 
  - BPF implement task local storage for BPF LSM
 
  - allow the FENTRY/FEXIT/RAW_TP tracing programs to use bpf_sk_storage
 
 Protocols:
 
  - mptcp: improve multiple xmit streams support, memory accounting and
           many smaller improvements
 
  - TLS: support CHACHA20-POLY1305 cipher
 
  - seg6: add support for SRv6 End.DT4/DT6 behavior
 
  - sctp: Implement RFC 6951: UDP Encapsulation of SCTP
 
  - ppp_generic: add ability to bridge channels directly
 
  - bridge: Connectivity Fault Management (CFM) support as is defined in
            IEEE 802.1Q section 12.14.
 
 Drivers:
 
  - mlx5: make use of the new auxiliary bus to organize the driver internals
 
  - mlx5: more accurate port TX timestamping support
 
  - mlxsw:
    - improve the efficiency of offloaded next hop updates by using
      the new nexthop object API
    - support blackhole nexthops
    - support IEEE 802.1ad (Q-in-Q) bridging
 
  - rtw88: major bluetooth co-existance improvements
 
  - iwlwifi: support new 6 GHz frequency band
 
  - ath11k: Fast Initial Link Setup (FILS)
 
  - mt7915: dual band concurrent (DBDC) support
 
  - net: ipa: add basic support for IPA v4.5
 
 Refactor:
 
  - a few pieces of in_interrupt() cleanup work from Sebastian Andrzej Siewior
 
  - phy: add support for shared interrupts; get rid of multiple driver
         APIs and have the drivers write a full IRQ handler, slight growth
 	of driver code should be compensated by the simpler API which
 	also allows shared IRQs
 
  - add common code for handling netdev per-cpu counters
 
  - move TX packet re-allocation from Ethernet switch tag drivers to
    a central place
 
  - improve efficiency and rename nla_strlcpy
 
  - number of W=1 warning cleanups as we now catch those in a patchwork
    build bot
 
 Old code removal:
 
  - wan: delete the DLCI / SDLA drivers
 
  - wimax: move to staging
 
  - wifi: remove old WDS wifi bridging support
 
 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-next-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Jakub Kicinski:
 "Core:

   - support "prefer busy polling" NAPI operation mode, where we defer
     softirq for some time expecting applications to periodically busy
     poll

   - AF_XDP: improve efficiency by more batching and hindering the
     adjacency cache prefetcher

   - af_packet: make packet_fanout.arr size configurable up to 64K

   - tcp: optimize TCP zero copy receive in presence of partial or
     unaligned reads making zero copy a performance win for much smaller
     messages

   - XDP: add bulk APIs for returning / freeing frames

   - sched: support fragmenting IP packets as they come out of conntrack

   - net: allow virtual netdevs to forward UDP L4 and fraglist GSO skbs

  BPF:

   - BPF switch from crude rlimit-based to memcg-based memory accounting

   - BPF type format information for kernel modules and related tracing
     enhancements

   - BPF implement task local storage for BPF LSM

   - allow the FENTRY/FEXIT/RAW_TP tracing programs to use
     bpf_sk_storage

  Protocols:

   - mptcp: improve multiple xmit streams support, memory accounting and
     many smaller improvements

   - TLS: support CHACHA20-POLY1305 cipher

   - seg6: add support for SRv6 End.DT4/DT6 behavior

   - sctp: Implement RFC 6951: UDP Encapsulation of SCTP

   - ppp_generic: add ability to bridge channels directly

   - bridge: Connectivity Fault Management (CFM) support as is defined
     in IEEE 802.1Q section 12.14.

  Drivers:

   - mlx5: make use of the new auxiliary bus to organize the driver
     internals

   - mlx5: more accurate port TX timestamping support

   - mlxsw:
      - improve the efficiency of offloaded next hop updates by using
        the new nexthop object API
      - support blackhole nexthops
      - support IEEE 802.1ad (Q-in-Q) bridging

   - rtw88: major bluetooth co-existance improvements

   - iwlwifi: support new 6 GHz frequency band

   - ath11k: Fast Initial Link Setup (FILS)

   - mt7915: dual band concurrent (DBDC) support

   - net: ipa: add basic support for IPA v4.5

  Refactor:

   - a few pieces of in_interrupt() cleanup work from Sebastian Andrzej
     Siewior

   - phy: add support for shared interrupts; get rid of multiple driver
     APIs and have the drivers write a full IRQ handler, slight growth
     of driver code should be compensated by the simpler API which also
     allows shared IRQs

   - add common code for handling netdev per-cpu counters

   - move TX packet re-allocation from Ethernet switch tag drivers to a
     central place

   - improve efficiency and rename nla_strlcpy

   - number of W=1 warning cleanups as we now catch those in a patchwork
     build bot

  Old code removal:

   - wan: delete the DLCI / SDLA drivers

   - wimax: move to staging

   - wifi: remove old WDS wifi bridging support"

* tag 'net-next-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1922 commits)
  net: hns3: fix expression that is currently always true
  net: fix proc_fs init handling in af_packet and tls
  nfc: pn533: convert comma to semicolon
  af_vsock: Assign the vsock transport considering the vsock address flags
  af_vsock: Set VMADDR_FLAG_TO_HOST flag on the receive path
  vsock_addr: Check for supported flag values
  vm_sockets: Add VMADDR_FLAG_TO_HOST vsock flag
  vm_sockets: Add flags field in the vsock address data structure
  net: Disable NETIF_F_HW_TLS_TX when HW_CSUM is disabled
  tcp: Add logic to check for SYN w/ data in tcp_simple_retransmit
  net: mscc: ocelot: install MAC addresses in .ndo_set_rx_mode from process context
  nfc: s3fwrn5: Release the nfc firmware
  net: vxget: clean up sparse warnings
  mlxsw: spectrum_router: Use eXtended mezzanine to offload IPv4 router
  mlxsw: spectrum: Set KVH XLT cache mode for Spectrum2/3
  mlxsw: spectrum_router_xm: Introduce basic XM cache flushing
  mlxsw: reg: Add Router LPM Cache Enable Register
  mlxsw: reg: Add Router LPM Cache ML Delete Register
  mlxsw: spectrum_router_xm: Implement L-value tracking for M-index
  mlxsw: reg: Add XM Router M Table Register
  ...
2020-12-15 13:22:29 -08:00
Jakub Kicinski a6b5e026e6 Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
pull-request: bpf-next 2020-12-14

1) Expose bpf_sk_storage_*() helpers to iterator programs, from Florent Revest.

2) Add AF_XDP selftests based on veth devs to BPF selftests, from Weqaar Janjua.

3) Support for finding BTF based kernel attach targets through libbpf's
   bpf_program__set_attach_target() API, from Andrii Nakryiko.

4) Permit pointers on stack for helper calls in the verifier, from Yonghong Song.

5) Fix overflows in hash map elem size after rlimit removal, from Eric Dumazet.

6) Get rid of direct invocation of llc in BPF selftests, from Andrew Delgadillo.

7) Fix xsk_recvmsg() to reorder socket state check before access, from Björn Töpel.

8) Add new libbpf API helper to retrieve ring buffer epoll fd, from Brendan Jackman.

9) Batch of minor BPF selftest improvements all over the place, from Florian Lehner,
   KP Singh, Jiri Olsa and various others.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (31 commits)
  selftests/bpf: Add a test for ptr_to_map_value on stack for helper access
  bpf: Permits pointers on stack for helper calls
  libbpf: Expose libbpf ring_buffer epoll_fd
  selftests/bpf: Add set_attach_target() API selftest for module target
  libbpf: Support modules in bpf_program__set_attach_target() API
  selftests/bpf: Silence ima_setup.sh when not running in verbose mode.
  selftests/bpf: Drop the need for LLVM's llc
  selftests/bpf: fix bpf_testmod.ko recompilation logic
  samples/bpf: Fix possible hang in xdpsock with multiple threads
  selftests/bpf: Make selftest compilation work on clang 11
  selftests/bpf: Xsk selftests - adding xdpxceiver to .gitignore
  selftests/bpf: Drop tcp-{client,server}.py from Makefile
  selftests/bpf: Xsk selftests - Bi-directional Sockets - SKB, DRV
  selftests/bpf: Xsk selftests - Socket Teardown - SKB, DRV
  selftests/bpf: Xsk selftests - DRV POLL, NOPOLL
  selftests/bpf: Xsk selftests - SKB POLL, NOPOLL
  selftests/bpf: Xsk selftests framework
  bpf: Only provide bpf_sock_from_file with CONFIG_NET
  bpf: Return -ENOTSUPP when attaching to non-kernel BTF
  xsk: Validate socket state in xsk_recvmsg, prior touching socket members
  ...
====================

Link: https://lore.kernel.org/r/20201214214316.20642-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-12-14 15:34:36 -08:00
Jens Axboe 355fb9e2b7 io_uring: remove 'twa_signal_ok' deadlock work-around
The TIF_NOTIFY_SIGNAL based implementation of TWA_SIGNAL is always safe
to use, regardless of context, as we won't be recursing into the signal
lock. So now that all archs are using that, we can drop this deadlock
work-around as it's always safe to use TWA_SIGNAL.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-12 09:17:38 -07:00
Jens Axboe 792ee0f6db io_uring: JOBCTL_TASK_WORK is no longer used by task_work
Remove the dead code, TWA_SIGNAL will never set JOBCTL_TASK_WORK at
this point.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-12 09:17:38 -07:00
Eric W. Biederman 9fe83c43e7 file: Rename __close_fd_get_file close_fd_get_file
The function close_fd_get_file is explicitly a variant of
__close_fd[1].  Now that __close_fd has been renamed close_fd, rename
close_fd_get_file to be consistent with close_fd.

When __alloc_fd, __close_fd and __fd_install were introduced the
double underscore indicated that the function took a struct
files_struct parameter.  The function __close_fd_get_file never has so
the naming has always been inconsistent.  This just cleans things up
so there are not any lingering mentions or references __close_fd left
in the code.

[1] 80cd795630 ("binder: fix use-after-free due to ksys_close() during fdget()")
Link: https://lkml.kernel.org/r/20201120231441.29911-23-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2020-12-10 12:42:59 -06:00
Pavel Begunkov 59850d226e io_uring: fix io_cqring_events()'s noflush
Checking !list_empty(&ctx->cq_overflow_list) around noflush in
io_cqring_events() is racy, because if it fails but a request overflowed
just after that, io_cqring_overflow_flush() still will be called.

Remove the second check, it shouldn't be a problem for performance,
because there is cq_check_overflow bit check just above.

Cc: <stable@vger.kernel.org> # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:02 -07:00
Pavel Begunkov 634578f800 io_uring: fix racy IOPOLL flush overflow
It's not safe to call io_cqring_overflow_flush() for IOPOLL mode without
hodling uring_lock, because it does synchronisation differently. Make
sure we have it.

As for io_ring_exit_work(), we don't even need it there because
io_ring_ctx_wait_and_kill() already set force flag making all overflowed
requests to be dropped.

Cc: <stable@vger.kernel.org> # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:01 -07:00
Pavel Begunkov 31bff9a51b io_uring: fix racy IOPOLL completions
IOPOLL allows buffer remove/provide requests, but they doesn't
synchronise by rules of IOPOLL, namely it have to hold uring_lock.

Cc: <stable@vger.kernel.org> # 5.7+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:01 -07:00
Xiaoguang Wang dad1b1242f io_uring: always let io_iopoll_complete() complete polled io
Abaci Fuzz reported a double-free or invalid-free BUG in io_commit_cqring():
[   95.504842] BUG: KASAN: double-free or invalid-free in io_commit_cqring+0x3ec/0x8e0
[   95.505921]
[   95.506225] CPU: 0 PID: 4037 Comm: io_wqe_worker-0 Tainted: G    B
W         5.10.0-rc5+ #1
[   95.507434] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
[   95.508248] Call Trace:
[   95.508683]  dump_stack+0x107/0x163
[   95.509323]  ? io_commit_cqring+0x3ec/0x8e0
[   95.509982]  print_address_description.constprop.0+0x3e/0x60
[   95.510814]  ? vprintk_func+0x98/0x140
[   95.511399]  ? io_commit_cqring+0x3ec/0x8e0
[   95.512036]  ? io_commit_cqring+0x3ec/0x8e0
[   95.512733]  kasan_report_invalid_free+0x51/0x80
[   95.513431]  ? io_commit_cqring+0x3ec/0x8e0
[   95.514047]  __kasan_slab_free+0x141/0x160
[   95.514699]  kfree+0xd1/0x390
[   95.515182]  io_commit_cqring+0x3ec/0x8e0
[   95.515799]  __io_req_complete.part.0+0x64/0x90
[   95.516483]  io_wq_submit_work+0x1fa/0x260
[   95.517117]  io_worker_handle_work+0xeac/0x1c00
[   95.517828]  io_wqe_worker+0xc94/0x11a0
[   95.518438]  ? io_worker_handle_work+0x1c00/0x1c00
[   95.519151]  ? __kthread_parkme+0x11d/0x1d0
[   95.519806]  ? io_worker_handle_work+0x1c00/0x1c00
[   95.520512]  ? io_worker_handle_work+0x1c00/0x1c00
[   95.521211]  kthread+0x396/0x470
[   95.521727]  ? _raw_spin_unlock_irq+0x24/0x30
[   95.522380]  ? kthread_mod_delayed_work+0x180/0x180
[   95.523108]  ret_from_fork+0x22/0x30
[   95.523684]
[   95.523985] Allocated by task 4035:
[   95.524543]  kasan_save_stack+0x1b/0x40
[   95.525136]  __kasan_kmalloc.constprop.0+0xc2/0xd0
[   95.525882]  kmem_cache_alloc_trace+0x17b/0x310
[   95.533930]  io_queue_sqe+0x225/0xcb0
[   95.534505]  io_submit_sqes+0x1768/0x25f0
[   95.535164]  __x64_sys_io_uring_enter+0x89e/0xd10
[   95.535900]  do_syscall_64+0x33/0x40
[   95.536465]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   95.537199]
[   95.537505] Freed by task 4035:
[   95.538003]  kasan_save_stack+0x1b/0x40
[   95.538599]  kasan_set_track+0x1c/0x30
[   95.539177]  kasan_set_free_info+0x1b/0x30
[   95.539798]  __kasan_slab_free+0x112/0x160
[   95.540427]  kfree+0xd1/0x390
[   95.540910]  io_commit_cqring+0x3ec/0x8e0
[   95.541516]  io_iopoll_complete+0x914/0x1390
[   95.542150]  io_do_iopoll+0x580/0x700
[   95.542724]  io_iopoll_try_reap_events.part.0+0x108/0x200
[   95.543512]  io_ring_ctx_wait_and_kill+0x118/0x340
[   95.544206]  io_uring_release+0x43/0x50
[   95.544791]  __fput+0x28d/0x940
[   95.545291]  task_work_run+0xea/0x1b0
[   95.545873]  do_exit+0xb6a/0x2c60
[   95.546400]  do_group_exit+0x12a/0x320
[   95.546967]  __x64_sys_exit_group+0x3f/0x50
[   95.547605]  do_syscall_64+0x33/0x40
[   95.548155]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

The reason is that once we got a non EAGAIN error in io_wq_submit_work(),
we'll complete req by calling io_req_complete(), which will hold completion_lock
to call io_commit_cqring(), but for polled io, io_iopoll_complete() won't
hold completion_lock to call io_commit_cqring(), then there maybe concurrent
access to ctx->defer_list, double free may happen.

To fix this bug, we always let io_iopoll_complete() complete polled io.

Cc: <stable@vger.kernel.org> # 5.5+
Reported-by: Abaci Fuzz <abaci@linux.alibaba.com>
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:01 -07:00
Pavel Begunkov 9c8e11b36c io_uring: add timeout update
Support timeout updates through IORING_OP_TIMEOUT_REMOVE with passed in
IORING_TIMEOUT_UPDATE. Updates doesn't support offset timeout mode.
Oirignal timeout.off will be ignored as well.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: remove now unused 'ret' variable]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:01 -07:00
Pavel Begunkov fbd15848f3 io_uring: restructure io_timeout_cancel()
Add io_timeout_extract() helper, which searches and disarms timeouts,
but doesn't complete them. No functional changes.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:01 -07:00
Pavel Begunkov bee749b187 io_uring: fix files cancellation
io_uring_cancel_files()'s task check condition mistakenly got flipped.

1. There can't be a request in the inflight list without
IO_WQ_WORK_FILES, kill this check to keep the whole condition simpler.
2. Also, don't call the function for files==NULL to not do such a check,
all that staff is already handled well by its counter part,
__io_uring_cancel_task_requests().

With that just flip the task check.

Also, it iowq-cancels all request of current task there, don't forget to
set right ->files into struct io_task_cancel.

Fixes: c1973b38bf639 ("io_uring: cancel only requests of current task")
Reported-by: syzbot+c0d52d0b3c0c3ffb9525@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:01 -07:00
Jens Axboe ac0648a56c io_uring: use bottom half safe lock for fixed file data
io_file_data_ref_zero() can be invoked from soft-irq from the RCU core,
hence we need to ensure that the file_data lock is bottom half safe. Use
the _bh() variants when grabbing this lock.

Reported-by: syzbot+1f4ba1e5520762c523c6@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:01 -07:00
Pavel Begunkov bd5bbda72f io_uring: fix miscounting ios_left
io_req_init() doesn't decrement state->ios_left if a request doesn't
need ->file, it just returns before that on if(!needs_file). That's
not really a problem but may cause overhead for an additional fput().
Also inline and kill io_req_set_file() as it's of no use anymore.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:01 -07:00
Pavel Begunkov 6e1271e60c io_uring: change submit file state invariant
Keep submit state invariant of whether there are file refs left based on
state->nr_refs instead of (state->file==NULL), and always check against
the first one. It's easier to track and allows to remove 1 if. It also
automatically leaves struct submit_state in a consistent state after
io_submit_state_end(), that's not used yet but nice.

btw rename has_refs to file_refs for more clarity.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:01 -07:00
Xiaoguang Wang 65b2b21348 io_uring: check kthread stopped flag when sq thread is unparked
syzbot reports following issue:
INFO: task syz-executor.2:12399 can't die for more than 143 seconds.
task:syz-executor.2  state:D stack:28744 pid:12399 ppid:  8504 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:3773 [inline]
 __schedule+0x893/0x2170 kernel/sched/core.c:4522
 schedule+0xcf/0x270 kernel/sched/core.c:4600
 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1847
 do_wait_for_common kernel/sched/completion.c:85 [inline]
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x163/0x260 kernel/sched/completion.c:138
 kthread_stop+0x17a/0x720 kernel/kthread.c:596
 io_put_sq_data fs/io_uring.c:7193 [inline]
 io_sq_thread_stop+0x452/0x570 fs/io_uring.c:7290
 io_finish_async fs/io_uring.c:7297 [inline]
 io_sq_offload_create fs/io_uring.c:8015 [inline]
 io_uring_create fs/io_uring.c:9433 [inline]
 io_uring_setup+0x19b7/0x3730 fs/io_uring.c:9507
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45deb9
Code: Unable to access opcode bytes at RIP 0x45de8f.
RSP: 002b:00007f174e51ac78 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9
RAX: ffffffffffffffda RBX: 0000000000008640 RCX: 000000000045deb9
RDX: 0000000000000000 RSI: 0000000020000140 RDI: 00000000000050e5
RBP: 000000000118bf58 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007ffed9ca723f R14: 00007f174e51b9c0 R15: 000000000118bf2c
INFO: task syz-executor.2:12399 blocked for more than 143 seconds.
      Not tainted 5.10.0-rc3-next-20201110-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

Currently we don't have a reproducer yet, but seems that there is a
race in current codes:
=> io_put_sq_data
      ctx_list is empty now.       |
==> kthread_park(sqd->thread);     |
                                   | T1: sq thread is parked now.
==> kthread_stop(sqd->thread);     |
    KTHREAD_SHOULD_STOP is set now.|
===> kthread_unpark(k);            |
                                   | T2: sq thread is now unparkd, run again.
                                   |
                                   | T3: sq thread is now preempted out.
                                   |
===> wake_up_process(k);           |
                                   |
                                   | T4: Since sqd ctx_list is empty, needs_sched will be true,
                                   | then sq thread sets task state to TASK_INTERRUPTIBLE,
                                   | and schedule, now sq thread will never be waken up.
===> wait_for_completion           |

I have artificially used mdelay() to simulate above race, will get same
stack like this syzbot report, but to be honest, I'm not sure this code
race triggers syzbot report.

To fix this possible code race, when sq thread is unparked, need to check
whether sq thread has been stopped.

Reported-by: syzbot+03beeb595f074db9cfd1@syzkaller.appspotmail.com
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:01 -07:00
Pavel Begunkov 36f72fe279 io_uring: share fixed_file_refs b/w multiple rsrcs
Double fixed files for splice/tee are done in a nasty way, it takes 2
ref_node refs, and during the second time it blindly overrides
req->fixed_file_refs hoping that it haven't changed. That works because
all that is done under iouring_lock in a single go but is error-prone.

Bind everything explicitly to a single ref_node and take only one ref,
with current ref_node ordering it's guaranteed to keep all files valid
awhile the request is inflight.

That's mainly a cleanup + preparation for generic resource handling,
but also saves pcpu_ref get/put for splice/tee with 2 fixed files.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:01 -07:00
Pavel Begunkov c98de08c99 io_uring: replace inflight_wait with tctx->wait
As tasks now cancel only theirs requests, and inflight_wait is awaited
only in io_uring_cancel_files(), which should be called with ->in_idle
set, instead of keeping a separate inflight_wait use tctx->wait.

That will add some spurious wakeups but actually is safer from point of
not hanging the task.

e.g.
task1                   | IRQ
                        | *start* io_complete_rw_common(link)
                        |        link: req1 -> req2 -> req3(with files)
*cancel_files()         |
io_wq_cancel(), etc.    |
                        | put_req(link), adds to io-wq req2
schedule()              |

So, task1 will never try to cancel req2 or req3. If req2 is
long-standing (e.g. read(empty_pipe)), this may hang.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:01 -07:00
Pavel Begunkov 10cad2c40d io_uring: don't take fs for recvmsg/sendmsg
We don't even allow not plain data msg_control, which is disallowed in
__sys_{send,revb}msg_sock(). So no need in fs for IORING_OP_SENDMSG and
IORING_OP_RECVMSG. fs->lock is less contanged not as much as before, but
there are cases that can be, e.g. IOSQE_ASYNC.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:01 -07:00
Xiaoguang Wang 2e9dbe902d io_uring: only wake up sq thread while current task is in io worker context
If IORING_SETUP_SQPOLL is enabled, sqes are either handled in sq thread
task context or in io worker task context. If current task context is sq
thread, we don't need to check whether should wake up sq thread.

io_iopoll_req_issued() calls wq_has_sleeper(), which has smp_mb() memory
barrier, before this patch, perf shows obvious overhead:
  Samples: 481K of event 'cycles', Event count (approx.): 299807382878
  Overhead  Comma  Shared Object     Symbol
     3.69%  :9630  [kernel.vmlinux]  [k] io_issue_sqe

With this patch, perf shows:
  Samples: 482K of event 'cycles', Event count (approx.): 299929547283
  Overhead  Comma  Shared Object     Symbol
     0.70%  :4015  [kernel.vmlinux]  [k] io_issue_sqe

It shows some obvious improvements.

Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:00 -07:00
Xiaoguang Wang 906a3c6f9c io_uring: don't acquire uring_lock twice
Both IOPOLL and sqes handling need to acquire uring_lock, combine
them together, then we just need to acquire uring_lock once.

Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:00 -07:00
Xiaoguang Wang a0d9205f7d io_uring: initialize 'timeout' properly in io_sq_thread()
Some static checker reports below warning:
    fs/io_uring.c:6939 io_sq_thread()
    error: uninitialized symbol 'timeout'.

This is a false positive, but let's just initialize 'timeout' to make
sure we don't trip over this.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:00 -07:00
Xiaoguang Wang 0836924634 io_uring: refactor io_sq_thread() handling
There are some issues about current io_sq_thread() implementation:
  1. The prepare_to_wait() usage in __io_sq_thread() is weird. If
multiple ctxs share one same poll thread, one ctx will put poll thread
in TASK_INTERRUPTIBLE, but if other ctxs have work to do, we don't
need to change task's stat at all. I think only if all ctxs don't have
work to do, we can do it.
  2. We use round-robin strategy to make multiple ctxs share one same
poll thread, but there are various condition in __io_sq_thread(), which
seems complicated and may affect round-robin strategy.

To improve above issues, I take below actions:
  1. If multiple ctxs share one same poll thread, only if all all ctxs
don't have work to do, we can call prepare_to_wait() and schedule() to
make poll thread enter sleep state.
  2. To make round-robin strategy more straight, I simplify
__io_sq_thread() a bit, it just does io poll and sqes submit work once,
does not check various condition.
  3. For multiple ctxs share one same poll thread, we choose the biggest
sq_thread_idle among these ctxs as timeout condition, and will update
it when ctx is in or out.
  4. Not need to check EBUSY especially, if io_submit_sqes() returns
EBUSY, IORING_SQ_CQ_OVERFLOW should be set, helper in liburing should
be aware of cq overflow and enters kernel to flush work.

Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:00 -07:00
Pavel Begunkov f6edbabb83 io_uring: always batch cancel in *cancel_files()
Instead of iterating over each request and cancelling it individually in
io_uring_cancel_files(), try to cancel all matching requests and use
->inflight_list only to check if there anything left.

In many cases it should be faster, and we can reuse a lot of code from
task cancellation.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:00 -07:00
Pavel Begunkov 6b81928d4c io_uring: pass files into kill timeouts/poll
Make io_poll_remove_all() and io_kill_timeouts() to match against files
as well. A preparation patch, effectively not used by now.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:00 -07:00
Pavel Begunkov b52fda00dd io_uring: don't iterate io_uring_cancel_files()
io_uring_cancel_files() guarantees to cancel all matching requests,
that's not necessary to do that in a loop. Move it up in the callchain
into io_uring_cancel_task_requests().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:00 -07:00
Pavel Begunkov df9923f967 io_uring: cancel only requests of current task
io_uring_cancel_files() cancels all request that match files regardless
of task. There is no real need in that, cancel only requests of the
specified task. That also handles SQPOLL case as it already changes task
to it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:00 -07:00
Pavel Begunkov 08d2363464 io_uring: add a {task,files} pair matching helper
Add io_match_task() that matches both task and files.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:00 -07:00
Pavel Begunkov 06de5f5973 io_uring: simplify io_task_match()
If IORING_SETUP_SQPOLL is set all requests belong to the corresponding
SQPOLL task, so skip task checking in that case and always match.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:00 -07:00
Pavel Begunkov 2846c481c9 io_uring: inline io_import_iovec()
Inline io_import_iovec() and leave only its former __io_import_iovec()
renamed to the original name. That makes it more obious what is reused in
io_read/write().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:00 -07:00
Pavel Begunkov 632546c4b5 io_uring: remove duplicated io_size from rw
io_size and iov_count in io_read() and io_write() hold the same value,
kill the last one.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:00 -07:00
David Laight 10fc72e433 fs/io_uring Don't use the return value from import_iovec().
This is the only code that relies on import_iovec() returning
iter.count on success.
This allows a better interface to import_iovec().

Signed-off-by: David Laight <david.laight@aculab.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:04:00 -07:00
Pavel Begunkov 1a38ffc9cb io_uring: NULL files dereference by SQPOLL
SQPOLL task may find sqo_task->files == NULL and
__io_sq_thread_acquire_files() would leave it unset, so following
fget_many() and others try to dereference NULL and fault. Propagate
an error files are missing.

[  118.962785] BUG: kernel NULL pointer dereference, address:
	0000000000000020
[  118.963812] #PF: supervisor read access in kernel mode
[  118.964534] #PF: error_code(0x0000) - not-present page
[  118.969029] RIP: 0010:__fget_files+0xb/0x80
[  119.005409] Call Trace:
[  119.005651]  fget_many+0x2b/0x30
[  119.005964]  io_file_get+0xcf/0x180
[  119.006315]  io_submit_sqes+0x3a4/0x950
[  119.007481]  io_sq_thread+0x1de/0x6a0
[  119.007828]  kthread+0x114/0x150
[  119.008963]  ret_from_fork+0x22/0x30

Reported-by: Josef Grieb <josef.grieb@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:03:59 -07:00
Hao Xu c73ebb685f io_uring: add timeout support for io_uring_enter()
Now users who want to get woken when waiting for events should submit a
timeout command first. It is not safe for applications that split SQ and
CQ handling between two threads, such as mysql. Users should synchronize
the two threads explicitly to protect SQ and that will impact the
performance.

This patch adds support for timeout to existing io_uring_enter(). To
avoid overloading arguments, it introduces a new parameter structure
which contains sigmask and timeout.

I have tested the workloads with one thread submiting nop requests
while the other reaping the cqe with timeout. It shows 1.8~2x faster
when the iodepth is 16.

Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
[axboe: various cleanups/fixes, and name change to SIG_IS_DATA]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:03:59 -07:00
Jens Axboe 27926b683d io_uring: only plug when appropriate
We unconditionally call blk_start_plug() when starting the IO
submission, but we only really should do that if we have more than 1
request to submit AND we're potentially dealing with block based storage
underneath. For any other type of request, it's just a waste of time to
do so.

Add a ->plug bit to io_op_def and set it for read/write requests. We
could make this more precise and check the file itself as well, but it
doesn't matter that much and would quickly become more expensive.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:03:59 -07:00
Pavel Begunkov 0415767e7f io_uring: rearrange io_kiocb fields for better caching
We've got extra 8 bytes in the 2nd cacheline, put ->fixed_file_refs
there, so inline execution path mostly doesn't touch the 3rd cacheline
for fixed_file requests as well.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:03:59 -07:00
Pavel Begunkov f2f87370bb io_uring: link requests with singly linked list
Singly linked list for keeping linked requests is enough, because we
almost always operate on the head and traverse forward with the
exception of linked timeouts going 1 hop backwards.

Replace ->link_list with a handmade singly linked list. Also kill
REQ_F_LINK_HEAD in favour of checking a newly added ->list for NULL
directly.

That saves 8B in io_kiocb, is not as heavy as list fixup, makes better
use of cache by not touching a previous request (i.e. last request of
the link) each time on list modification and optimises cache use further
in the following patch, and actually makes travesal easier removing in
the end some lines. Also, keeping invariant in ->list instead of having
REQ_F_LINK_HEAD is less error-prone.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:03:59 -07:00
Pavel Begunkov 90cd7e4249 io_uring: track link timeout's master explicitly
In preparation for converting singly linked lists for chaining requests,
make linked timeouts save requests that they're responsible for and not
count on doubly linked list for back referencing.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:03:59 -07:00
Pavel Begunkov 863e05604a io_uring: track link's head and tail during submit
Explicitly save not only a link's head in io_submit_sqe[s]() but the
tail as well. That's in preparation for keeping linked requests in a
singly linked list.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:03:59 -07:00
Pavel Begunkov 018043be1f io_uring: split poll and poll_remove structs
Don't use a single struct for polls and poll remove requests, they have
totally different layouts.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:03:59 -07:00
Jens Axboe 14a1143b68 io_uring: add support for IORING_OP_UNLINKAT
IORING_OP_UNLINKAT behaves like unlinkat(2) and takes the same flags
and arguments.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:03:59 -07:00
Jens Axboe 80a261fd00 io_uring: add support for IORING_OP_RENAMEAT
IORING_OP_RENAMEAT behaves like renameat2(), and takes the same flags
etc.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:03:59 -07:00
Jens Axboe 14587a4664 io_uring: enable file table usage for SQPOLL rings
Now that SQPOLL supports non-registered files and grabs the file table,
we can relax the restriction on open/close/accept/connect and allow
them on a ring that is setup with IORING_SETUP_SQPOLL.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:03:59 -07:00
Jens Axboe 28cea78af4 io_uring: allow non-fixed files with SQPOLL
The restriction of needing fixed files for SQPOLL is problematic, and
prevents/inhibits several valid uses cases. With the referenced
files_struct that we have now, it's trivially supportable.

Treat ->files like we do the mm for the SQPOLL thread - grab a reference
to it (and assign it), and drop it when we're done.

This feature is exposed as IORING_FEAT_SQPOLL_NONFIXED.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-09 12:03:54 -07:00
Hillf Danton f26c08b444 io_uring: fix file leak on error path of io ctx creation
Put file as part of error handling when setting up io ctx to fix
memory leaks like the following one.

   BUG: memory leak
   unreferenced object 0xffff888101ea2200 (size 256):
     comm "syz-executor355", pid 8470, jiffies 4294953658 (age 32.400s)
     hex dump (first 32 bytes):
       00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
       20 59 03 01 81 88 ff ff 80 87 a8 10 81 88 ff ff   Y..............
     backtrace:
       [<000000002e0a7c5f>] kmem_cache_zalloc include/linux/slab.h:654 [inline]
       [<000000002e0a7c5f>] __alloc_file+0x1f/0x130 fs/file_table.c:101
       [<000000001a55b73a>] alloc_empty_file+0x69/0x120 fs/file_table.c:151
       [<00000000fb22349e>] alloc_file+0x33/0x1b0 fs/file_table.c:193
       [<000000006e1465bb>] alloc_file_pseudo+0xb2/0x140 fs/file_table.c:233
       [<000000007118092a>] anon_inode_getfile fs/anon_inodes.c:91 [inline]
       [<000000007118092a>] anon_inode_getfile+0xaa/0x120 fs/anon_inodes.c:74
       [<000000002ae99012>] io_uring_get_fd fs/io_uring.c:9198 [inline]
       [<000000002ae99012>] io_uring_create fs/io_uring.c:9377 [inline]
       [<000000002ae99012>] io_uring_setup+0x1125/0x1630 fs/io_uring.c:9411
       [<000000008280baad>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
       [<00000000685d8cf0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported-by: syzbot+71c4697e27c99fddcf17@syzkaller.appspotmail.com
Fixes: 0f2122045b ("io_uring: don't rely on weak ->files references")
Cc: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-08 08:54:26 -07:00
Pavel Begunkov e8c954df23 io_uring: fix mis-seting personality's creds
After io_identity_cow() copies an work.identity it wants to copy creds
to the new just allocated id, not the old one. Otherwise it's
akin to req->work.identity->creds = req->work.identity->creds.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-07 08:43:44 -07:00
Florent Revest dba4a9256b net: Remove the err argument from sock_from_file
Currently, the sock_from_file prototype takes an "err" pointer that is
either not set or set to -ENOTSOCK IFF the returned socket is NULL. This
makes the error redundant and it is ignored by a few callers.

This patch simplifies the API by letting callers deduce the error based
on whether the returned socket is NULL or not.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Florent Revest <revest@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: KP Singh <kpsingh@google.com>
Link: https://lore.kernel.org/bpf/20201204113609.1850150-1-revest@google.com
2020-12-04 22:32:40 +01:00
Christoph Hellwig 4e7b5671c6 block: remove i_bdev
Switch the block device lookup interfaces to directly work with a dev_t
so that struct block_device references are only acquired by the
blkdev_get variants (and the blk-cgroup special case).  This means that
we now don't need an extra reference in the inode and can generally
simplify handling of struct block_device to keep the lookups contained
in the core block layer code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Coly Li <colyli@suse.de>		[bcache]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-01 14:53:39 -07:00
Pavel Begunkov 2d280bc893 io_uring: fix recvmsg setup with compat buf-select
__io_compat_recvmsg_copy_hdr() with REQ_F_BUFFER_SELECT reads out iov
len but never assigns it to iov/fast_iov, leaving sr->len with garbage.
Hopefully, following io_buffer_select() truncates it to the selected
buffer size, but the value is still may be under what was specified.

Cc: <stable@vger.kernel.org> # 5.7
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-30 11:12:03 -07:00
Pavel Begunkov af60470347 io_uring: fix files grab/cancel race
When one task is in io_uring_cancel_files() and another is doing
io_prep_async_work() a race may happen. That's because after accounting
a request inflight in first call to io_grab_identity() it still may fail
and go to io_identity_cow(), which migh briefly keep dangling
work.identity and not only.

Grab files last, so io_prep_async_work() won't fail if it did get into
->inflight_list.

note: the bug shouldn't exist after making io_uring_cancel_files() not
poking into other tasks' requests.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-26 08:50:21 -07:00
Pavel Begunkov 9c3a205c5f io_uring: fix ITER_BVEC check
iov_iter::type is a bitmask that also keeps direction etc., so it
shouldn't be directly compared against ITER_*. Use proper helper.

Fixes: ff6165b2d7 ("io_uring: retain iov_iter state over io_read/io_write calls")
Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Cc: <stable@vger.kernel.org> # 5.9
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-24 07:54:30 -07:00
Joseph Qi eb2667b343 io_uring: fix shift-out-of-bounds when round up cq size
Abaci Fuzz reported a shift-out-of-bounds BUG in io_uring_create():

[ 59.598207] UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13
[ 59.599665] shift exponent 64 is too large for 64-bit type 'long unsigned int'
[ 59.601230] CPU: 0 PID: 963 Comm: a.out Not tainted 5.10.0-rc4+ #3
[ 59.602502] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
[ 59.603673] Call Trace:
[ 59.604286] dump_stack+0x107/0x163
[ 59.605237] ubsan_epilogue+0xb/0x5a
[ 59.606094] __ubsan_handle_shift_out_of_bounds.cold+0xb2/0x20e
[ 59.607335] ? lock_downgrade+0x6c0/0x6c0
[ 59.608182] ? rcu_read_lock_sched_held+0xaf/0xe0
[ 59.609166] io_uring_create.cold+0x99/0x149
[ 59.610114] io_uring_setup+0xd6/0x140
[ 59.610975] ? io_uring_create+0x2510/0x2510
[ 59.611945] ? lockdep_hardirqs_on_prepare+0x286/0x400
[ 59.613007] ? syscall_enter_from_user_mode+0x27/0x80
[ 59.614038] ? trace_hardirqs_on+0x5b/0x180
[ 59.615056] do_syscall_64+0x2d/0x40
[ 59.615940] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 59.617007] RIP: 0033:0x7f2bb8a0b239

This is caused by roundup_pow_of_two() if the input entries larger
enough, e.g. 2^32-1. For sq_entries, it will check first and we allow
at most IORING_MAX_ENTRIES, so it is okay. But for cq_entries, we do
round up first, that may overflow and truncate it to 0, which is not
the expected behavior. So check the cq size first and then do round up.

Fixes: 88ec3211e4 ("io_uring: round-up cq size before comparing with rounded sq size")
Reported-by: Abaci Fuzz <abaci@linux.alibaba.com>
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-24 07:54:30 -07:00
Jens Axboe 36f4fa6886 io_uring: add support for shutdown(2)
This adds support for the shutdown(2) system call, which is useful for
dealing with sockets.

shutdown(2) may block, so we have to punt it to async context.

Suggested-by: Norman Maurer <norman.maurer@googlemail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-23 09:15:15 -07:00
Jens Axboe ce59fc69b1 io_uring: allow SQPOLL with CAP_SYS_NICE privileges
CAP_SYS_ADMIN is too restrictive for a lot of uses cases, allow
CAP_SYS_NICE based on the premise that such users are already allowed
to raise the priority of tasks.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-23 09:15:15 -07:00
Linus Torvalds fa5fca78bb io_uring-5.10-2020-11-20
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Merge tag 'io_uring-5.10-2020-11-20' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:
 "Mostly regression or stable fodder:

   - Disallow async path resolution of /proc/self

   - Tighten constraints for segmented async buffered reads

   - Fix double completion for a retry error case

   - Fix for fixed file life times (Pavel)"

* tag 'io_uring-5.10-2020-11-20' of git://git.kernel.dk/linux-block:
  io_uring: order refnode recycling
  io_uring: get an active ref_node from files_data
  io_uring: don't double complete failed reissue request
  mm: never attempt async page lock if we've transferred data already
  io_uring: handle -EOPNOTSUPP on path resolution
  proc: don't allow async path resolution of /proc/self components
2020-11-20 11:47:22 -08:00
Pavel Begunkov e297822b20 io_uring: order refnode recycling
Don't recycle a refnode until we're done with all requests of nodes
ejected before.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-18 08:02:10 -07:00
Pavel Begunkov 1e5d770bb8 io_uring: get an active ref_node from files_data
An active ref_node always can be found in ctx->files_data, it's much
safer to get it this way instead of poking into files_data->ref_list.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-18 08:02:10 -07:00
Jens Axboe c993df5a68 io_uring: don't double complete failed reissue request
Zorro reports that an xfstest test case is failing, and it turns out that
for the reissue path we can potentially issue a double completion on the
request for the failure path. There's an issue around the retry as well,
but for now, at least just make sure that we handle the error path
correctly.

Cc: stable@vger.kernel.org
Fixes: b63534c41e ("io_uring: re-issue block requests that failed because of resources")
Reported-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-17 15:17:29 -07:00
Jens Axboe 944d1444d5 io_uring: handle -EOPNOTSUPP on path resolution
Any attempt to do path resolution on /proc/self from an async worker will
yield -EOPNOTSUPP. We can safely do that resolution from the task itself,
and without blocking, so retry it from there.

Ideally io_uring would know this upfront and not have to go through the
worker thread to find out, but that doesn't currently seem feasible.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-14 10:22:30 -07:00
Linus Torvalds f01c30de86 More VFS fixes for 5.10-rc4:
- Minor cleanups of the sb_start_* fs freeze helpers.
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Merge tag 'vfs-5.10-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull fs freeze fix and cleanups from Darrick Wong:
 "A single vfs fix for 5.10, along with two subsequent cleanups.

  A very long time ago, a hack was added to the vfs fs freeze protection
  code to work around lockdep complaints about XFS, which would try to
  run a transaction (which requires intwrite protection) to finalize an
  xfs freeze (by which time the vfs had already taken intwrite).

  Fast forward a few years, and XFS fixed the recursive intwrite problem
  on its own, and the hack became unnecessary. Fast forward almost a
  decade, and latent bugs in the code converting this hack from freeze
  flags to freeze locks combine with lockdep bugs to make this reproduce
  frequently enough to notice page faults racing with freeze.

  Since the hack is unnecessary and causes thread race errors, just get
  rid of it completely. Making this kind of vfs change midway through a
  cycle makes me nervous, but a large enough number of the usual
  VFS/ext4/XFS/btrfs suspects have said this looks good and solves a
  real problem vector.

  And once that removal is done, __sb_start_write is now simple enough
  that it becomes possible to refactor the function into smaller,
  simpler static inline helpers in linux/fs.h. The cleanup is
  straightforward.

  Summary:

   - Finally remove the "convert to trylock" weirdness in the fs freezer
     code. It was necessary 10 years ago to deal with nested
     transactions in XFS, but we've long since removed that; and now
     this is causing subtle race conditions when lockdep goes offline
     and sb_start_* aren't prepared to retry a trylock failure.

   - Minor cleanups of the sb_start_* fs freeze helpers"

* tag 'vfs-5.10-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  vfs: move __sb_{start,end}_write* to fs.h
  vfs: separate __sb_start_write into blocking and non-blocking helpers
  vfs: remove lockdep bogosity in __sb_start_write
2020-11-13 16:07:53 -08:00
Jens Axboe 88ec3211e4 io_uring: round-up cq size before comparing with rounded sq size
If an application specifies IORING_SETUP_CQSIZE to set the CQ ring size
to a specific size, we ensure that the CQ size is at least that of the
SQ ring size. But in doing so, we compare the already rounded up to power
of two SQ size to the as-of yet unrounded CQ size. This means that if an
application passes in non power of two sizes, we can return -EINVAL when
the final value would've been fine. As an example, an application passing
in 100/100 for sq/cq size should end up with 128 for both. But since we
round the SQ size first, we compare the CQ size of 100 to 128, and return
-EINVAL as that is too small.

Cc: stable@vger.kernel.org
Fixes: 33a107f0a1 ("io_uring: allow application controlled CQ ring size")
Reported-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-11 10:42:41 -07:00
Darrick J. Wong 8a3c84b649 vfs: separate __sb_start_write into blocking and non-blocking helpers
Break this function into two helpers so that it's obvious that the
trylock versions return a value that must be checked, and the blocking
versions don't require that.  While we're at it, clean up the return
type mismatch.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-11-10 16:53:07 -08:00
Pavel Begunkov 9a472ef7a3 io_uring: fix link lookup racing with link timeout
We can't just go over linked requests because it may race with linked
timeouts. Take ctx->completion_lock in that case.

Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-05 15:36:40 -07:00
Jens Axboe 6b47ab81c9 io_uring: use correct pointer for io_uring_show_cred()
Previous commit changed how we index the registered credentials, but
neglected to update one spot that is used when the personalities are
iterated through ->show_fdinfo(). Ensure we use the right struct type
for the iteration.

Reported-by: syzbot+a6d494688cdb797bdfce@syzkaller.appspotmail.com
Fixes: 1e6fa5216a ("io_uring: COW io_identity on mismatch")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-05 09:50:16 -07:00
Pavel Begunkov ef9865a442 io_uring: don't forget to task-cancel drained reqs
If there is a long-standing request of one task locking up execution of
deferred requests, and the defer list contains requests of another task
(all files-less), then a potential execution of __io_uring_task_cancel()
by that another task will sleep until that first long-standing request
completion, and that may take long.

E.g.
tsk1: req1/read(empty_pipe) -> tsk2: req(DRAIN)
Then __io_uring_task_cancel(tsk2) waits for req1 completion.

It seems we even can manufacture a complicated case with many tasks
sharing many rings that can lock them forever.

Cancel deferred requests for __io_uring_task_cancel() as well.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-05 09:15:24 -07:00
Pavel Begunkov 99b328084f io_uring: fix overflowed cancel w/ linked ->files
Current io_match_files() check in io_cqring_overflow_flush() is useless
because requests drop ->files before going to the overflow list, however
linked to it request do not, and we don't check them.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-04 10:22:57 -07:00
Jens Axboe cb8a8ae310 io_uring: drop req/tctx io_identity separately
We can't bundle this into one operation, as the identity may not have
originated from the tctx to begin with. Drop one ref for each of them
separately, if they don't match the static assignment. If we don't, then
if the identity is a lookup from registered credentials, we could be
freeing that identity as we're dropping a reference assuming it came from
the tctx. syzbot reports this as a use-after-free, as the identity is
still referencable from idr lookup:

==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: use-after-free in atomic_fetch_add_relaxed include/asm-generic/atomic-instrumented.h:142 [inline]
BUG: KASAN: use-after-free in __refcount_add include/linux/refcount.h:193 [inline]
BUG: KASAN: use-after-free in __refcount_inc include/linux/refcount.h:250 [inline]
BUG: KASAN: use-after-free in refcount_inc include/linux/refcount.h:267 [inline]
BUG: KASAN: use-after-free in io_init_req fs/io_uring.c:6700 [inline]
BUG: KASAN: use-after-free in io_submit_sqes+0x15a9/0x25f0 fs/io_uring.c:6774
Write of size 4 at addr ffff888011e08e48 by task syz-executor165/8487

CPU: 1 PID: 8487 Comm: syz-executor165 Not tainted 5.10.0-rc1-next-20201102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x4c8 mm/kasan/report.c:385
 __kasan_report mm/kasan/report.c:545 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562
 check_memory_region_inline mm/kasan/generic.c:186 [inline]
 check_memory_region+0x13d/0x180 mm/kasan/generic.c:192
 instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
 atomic_fetch_add_relaxed include/asm-generic/atomic-instrumented.h:142 [inline]
 __refcount_add include/linux/refcount.h:193 [inline]
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 io_init_req fs/io_uring.c:6700 [inline]
 io_submit_sqes+0x15a9/0x25f0 fs/io_uring.c:6774
 __do_sys_io_uring_enter+0xc8e/0x1b50 fs/io_uring.c:9159
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x440e19
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb 0f fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff644ff178 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000440e19
RDX: 0000000000000000 RSI: 000000000000450c RDI: 0000000000000003
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000022b4850
R13: 0000000000000010 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 8487:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:461
 kmalloc include/linux/slab.h:552 [inline]
 io_register_personality fs/io_uring.c:9638 [inline]
 __io_uring_register fs/io_uring.c:9874 [inline]
 __do_sys_io_uring_register+0x10f0/0x40a0 fs/io_uring.c:9924
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 8487:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
 __kasan_slab_free+0x102/0x140 mm/kasan/common.c:422
 slab_free_hook mm/slub.c:1544 [inline]
 slab_free_freelist_hook+0x5d/0x150 mm/slub.c:1577
 slab_free mm/slub.c:3140 [inline]
 kfree+0xdb/0x360 mm/slub.c:4122
 io_identity_cow fs/io_uring.c:1380 [inline]
 io_prep_async_work+0x903/0xbc0 fs/io_uring.c:1492
 io_prep_async_link fs/io_uring.c:1505 [inline]
 io_req_defer fs/io_uring.c:5999 [inline]
 io_queue_sqe+0x212/0xed0 fs/io_uring.c:6448
 io_submit_sqe fs/io_uring.c:6542 [inline]
 io_submit_sqes+0x14f6/0x25f0 fs/io_uring.c:6784
 __do_sys_io_uring_enter+0xc8e/0x1b50 fs/io_uring.c:9159
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff888011e08e00
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 72 bytes inside of
 96-byte region [ffff888011e08e00, ffff888011e08e60)
The buggy address belongs to the page:
page:00000000a7104751 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11e08
flags: 0xfff00000000200(slab)
raw: 00fff00000000200 ffffea00004f8540 0000001f00000002 ffff888010041780
raw: 0000000000000000 0000000080200020 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888011e08d00: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
 ffff888011e08d80: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
> ffff888011e08e00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                                              ^
 ffff888011e08e80: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
 ffff888011e08f00: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
==================================================================

Reported-by: syzbot+625ce3bb7835b63f7f3d@syzkaller.appspotmail.com
Fixes: 1e6fa5216a ("io_uring: COW io_identity on mismatch")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-04 10:22:57 -07:00
Jens Axboe 4b70cf9dea io_uring: ensure consistent view of original task ->mm from SQPOLL
Ensure we get a valid view of the task mm, by using task_lock() when
attempting to grab the original task mm.

Reported-by: syzbot+b57abf7ee60829090495@syzkaller.appspotmail.com
Fixes: 2aede0e417 ("io_uring: stash ctx task reference for SQPOLL")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-04 10:22:57 -07:00
Jens Axboe fdaf083cdf io_uring: properly handle SQPOLL request cancelations
Track if a given task io_uring context contains SQPOLL instances, so we
can iterate those for cancelation (and request counts). This ensures that
we properly wait on SQPOLL contexts, and find everything that needs
canceling.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-04 10:22:56 -07:00
Linus Torvalds cf9446cc8e io_uring-5.10-2020-10-30
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Merge tag 'io_uring-5.10-2020-10-30' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:

 - Fixes for linked timeouts (Pavel)

 - Set IO_WQ_WORK_CONCURRENT early for async offload (Pavel)

 - Two minor simplifications that make the code easier to read and
   follow (Pavel)

* tag 'io_uring-5.10-2020-10-30' of git://git.kernel.dk/linux-block:
  io_uring: use type appropriate io_kiocb handler for double poll
  io_uring: simplify __io_queue_sqe()
  io_uring: simplify nxt propagation in io_queue_sqe
  io_uring: don't miss setting IO_WQ_WORK_CONCURRENT
  io_uring: don't defer put of cancelled ltimeout
  io_uring: always clear LINK_TIMEOUT after cancel
  io_uring: don't adjust LINK_HEAD in cancel ltimeout
  io_uring: remove opcode check on ltimeout kill
2020-10-30 14:55:36 -07:00
Jens Axboe c8b5e2600a io_uring: use type appropriate io_kiocb handler for double poll
io_poll_double_wake() is called for both request types - both pure poll
requests, and internal polls. This means that we should be using the
right handler based on the request type. Use the one that the original
caller already assigned for the waitqueue handling, that will always
match the correct type.

Cc: stable@vger.kernel.org # v5.8+
Reported-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-25 13:53:26 -06:00
Linus Torvalds af0041875c io_uring-5.10-2020-10-24
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Merge tag 'io_uring-5.10-2020-10-24' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:

 - fsize was missed in previous unification of work flags

 - Few fixes cleaning up the flags unification creds cases (Pavel)

 - Fix NUMA affinities for completely unplugged/replugged node for io-wq

 - Two fallout fixes from the set_fs changes. One local to io_uring, one
   for the splice entry point that io_uring uses.

 - Linked timeout fixes (Pavel)

 - Removal of ->flush() ->files work-around that we don't need anymore
   with referenced files (Pavel)

 - Various cleanups (Pavel)

* tag 'io_uring-5.10-2020-10-24' of git://git.kernel.dk/linux-block:
  splice: change exported internal do_splice() helper to take kernel offset
  io_uring: make loop_rw_iter() use original user supplied pointers
  io_uring: remove req cancel in ->flush()
  io-wq: re-set NUMA node affinities if CPUs come online
  io_uring: don't reuse linked_timeout
  io_uring: unify fsize with def->work_flags
  io_uring: fix racy REQ_F_LINK_TIMEOUT clearing
  io_uring: do poll's hash_node init in common code
  io_uring: inline io_poll_task_handler()
  io_uring: remove extra ->file check in poll prep
  io_uring: make cached_cq_overflow non atomic_t
  io_uring: inline io_fail_links()
  io_uring: kill ref get/drop in personality init
  io_uring: flags-based creds init in queue
2020-10-24 12:40:18 -07:00
Pavel Begunkov 0d63c148d6 io_uring: simplify __io_queue_sqe()
Restructure __io_queue_sqe() so it follows simple if/else if/else
control flow. It's more readable and removes extra goto/labels.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-23 13:07:12 -06:00
Pavel Begunkov 9aaf354352 io_uring: simplify nxt propagation in io_queue_sqe
Don't overuse goto's, complex control flow doesn't make compilers happy
and makes code harder to read.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-23 13:07:12 -06:00
Pavel Begunkov feaadc4fc2 io_uring: don't miss setting IO_WQ_WORK_CONCURRENT
Set IO_WQ_WORK_CONCURRENT for all REQ_F_FORCE_ASYNC requests, do that in
that is also looks better.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-23 13:07:11 -06:00
Pavel Begunkov c9abd7ad83 io_uring: don't defer put of cancelled ltimeout
Inline io_link_cancel_timeout() and __io_kill_linked_timeout() into
io_kill_linked_timeout(). That allows to easily move a put of a cancelled
linked timeout out of completion_lock and to not deferring it. It is also
much more readable when not scattered across three different functions.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-23 13:07:11 -06:00
Pavel Begunkov cdfcc3ee04 io_uring: always clear LINK_TIMEOUT after cancel
Move REQ_F_LINK_TIMEOUT clearing out of __io_kill_linked_timeout()
because it might return early and leave the flag set. It's not a
problem, but may be confusing.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-23 13:07:11 -06:00
Pavel Begunkov ac877d2edd io_uring: don't adjust LINK_HEAD in cancel ltimeout
An armed linked timeout can never be a head of a link, so we don't need
to clear REQ_F_LINK_HEAD for it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-23 13:07:11 -06:00
Pavel Begunkov e08102d507 io_uring: remove opcode check on ltimeout kill
__io_kill_linked_timeout() already checks for REQ_F_LTIMEOUT_ACTIVE and
it's set only for linked timeouts. No need to verify next request's
opcode.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-23 13:07:11 -06:00
Linus Torvalds 4a22709e21 arch-cleanup-2020-10-22
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Merge tag 'arch-cleanup-2020-10-22' of git://git.kernel.dk/linux-block

Pull arch task_work cleanups from Jens Axboe:
 "Two cleanups that don't fit other categories:

   - Finally get the task_work_add() cleanup done properly, so we don't
     have random 0/1/false/true/TWA_SIGNAL confusing use cases. Updates
     all callers, and also fixes up the documentation for
     task_work_add().

   - While working on some TIF related changes for 5.11, this
     TIF_NOTIFY_RESUME cleanup fell out of that. Remove some arch
     duplication for how that is handled"

* tag 'arch-cleanup-2020-10-22' of git://git.kernel.dk/linux-block:
  task_work: cleanup notification modes
  tracehook: clear TIF_NOTIFY_RESUME in tracehook_notify_resume()
2020-10-23 10:06:38 -07:00
Jens Axboe 4017eb91a9 io_uring: make loop_rw_iter() use original user supplied pointers
We jump through a hoop for fixed buffers, where we first map these to
a bvec(), then kmap() the bvec to obtain the pointer we copy to/from.
This was always a bit ugly, and with the set_fs changes, it ends up
being practically problematic as well.

There's no need to jump through these hoops, just use the original user
pointers and length for the non iter based read/write.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-22 14:14:12 -06:00
Pavel Begunkov c8fb20b5b4 io_uring: remove req cancel in ->flush()
Every close(io_uring) causes cancellation of all inflight requests
carrying ->files. That's not nice but was neccessary up until recently.
Now task->files removal is handled in the core code, so that part of
flush can be removed.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-22 09:54:19 -06:00
Pavel Begunkov ff5771613c io_uring: don't reuse linked_timeout
Clear linked_timeout for next requests in __io_queue_sqe() so we won't
queue it up unnecessary when it's going to be punted.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Cc: stable@vger.kernel.org # v5.9
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-21 16:37:56 -06:00
Jens Axboe 69228338c9 io_uring: unify fsize with def->work_flags
This one was missed in the earlier conversion, should be included like
any of the other IO identity flags. Make sure we restore to RLIM_INIFITY
when dropping the personality again.

Fixes: 98447d65b4 ("io_uring: move io identity items into separate struct")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-20 16:03:13 -06:00
Linus Torvalds 4962a85696 io_uring-5.10-2020-10-20
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Merge tag 'io_uring-5.10-2020-10-20' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:
 "A mix of fixes and a few stragglers. In detail:

   - Revert the bogus __read_mostly that we discussed for the initial
     pull request.

   - Fix a merge window regression with fixed file registration error
     path handling.

   - Fix io-wq numa node affinities.

   - Series abstracting out an io_identity struct, making it both easier
     to see what the personality items are, and also easier to to adopt
     more. Use this to cover audit logging.

   - Fix for read-ahead disabled block condition in async buffered
     reads, and using single page read-ahead to unify what
     generic_file_buffer_read() path is used.

   - Series for REQ_F_COMP_LOCKED fix and removal of it (Pavel)

   - Poll fix (Pavel)"

* tag 'io_uring-5.10-2020-10-20' of git://git.kernel.dk/linux-block: (21 commits)
  io_uring: use blk_queue_nowait() to check if NOWAIT supported
  mm: use limited read-ahead to satisfy read
  mm: mark async iocb read as NOWAIT once some data has been copied
  io_uring: fix double poll mask init
  io-wq: inherit audit loginuid and sessionid
  io_uring: use percpu counters to track inflight requests
  io_uring: assign new io_identity for task if members have changed
  io_uring: store io_identity in io_uring_task
  io_uring: COW io_identity on mismatch
  io_uring: move io identity items into separate struct
  io_uring: rely solely on work flags to determine personality.
  io_uring: pass required context in as flags
  io-wq: assign NUMA node locality if appropriate
  io_uring: fix error path cleanup in io_sqe_files_register()
  Revert "io_uring: mark io_uring_fops/io_op_defs as __read_mostly"
  io_uring: fix REQ_F_COMP_LOCKED by killing it
  io_uring: dig out COMP_LOCK from deep call chain
  io_uring: don't put a poll req under spinlock
  io_uring: don't unnecessarily clear F_LINK_TIMEOUT
  io_uring: don't set COMP_LOCKED if won't put
  ...
2020-10-20 13:19:30 -07:00
Pavel Begunkov 900fad45dc io_uring: fix racy REQ_F_LINK_TIMEOUT clearing
io_link_timeout_fn() removes REQ_F_LINK_TIMEOUT from the link head's
flags, it's not atomic and may race with what the head is doing.

If io_link_timeout_fn() doesn't clear the flag, as forced by this patch,
then it may happen that for "req -> link_timeout1 -> link_timeout2",
__io_kill_linked_timeout() would find link_timeout2 and try to cancel
it, so miscounting references. Teach it to ignore such double timeouts
by marking the active one with a new flag in io_prep_linked_timeout().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-19 13:29:51 -06:00
Pavel Begunkov 4d52f33899 io_uring: do poll's hash_node init in common code
Move INIT_HLIST_NODE(&req->hash_node) into __io_arm_poll_handler(), so
that it doesn't duplicated and common poll code would be responsible for
it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-19 13:29:29 -06:00
Pavel Begunkov dd221f46f6 io_uring: inline io_poll_task_handler()
io_poll_task_handler() doesn't add clarity, inline it in its only user.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-19 13:29:29 -06:00
Pavel Begunkov 069b89384d io_uring: remove extra ->file check in poll prep
io_poll_add_prep() doesn't need to verify ->file because it's already
done in io_init_req().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-19 13:29:29 -06:00
Pavel Begunkov 2c3bac6dd6 io_uring: make cached_cq_overflow non atomic_t
ctx->cached_cq_overflow is changed only under completion_lock. Convert
it from atomic_t to just int, and mark all places when it's read without
lock with READ_ONCE, which guarantees atomicity (relaxed ordering).

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-19 13:29:29 -06:00
Pavel Begunkov d148ca4b07 io_uring: inline io_fail_links()
Inline io_fail_links() and kill extra io_cqring_ev_posted().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-19 13:29:29 -06:00
Pavel Begunkov ec99ca6c47 io_uring: kill ref get/drop in personality init
Don't take an identity on personality/creds init only to drop it a few
lines after. Extract a function which prepares req->work but leaves it
without identity.

Note: it's safe to not check REQ_F_WORK_INITIALIZED there because it's
nobody had a chance to init it before io_init_req().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-19 13:29:29 -06:00
Pavel Begunkov 2e5aa6cb4d io_uring: flags-based creds init in queue
Use IO_WQ_WORK_CREDS to figure out if req has creds to be used.
Since recently it should rely only on flags, but not value of
work.creds.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-19 13:29:29 -06:00
Jeffle Xu 9ba0d0c812 io_uring: use blk_queue_nowait() to check if NOWAIT supported
commit 021a24460d ("block: add QUEUE_FLAG_NOWAIT") adds a new helper
function blk_queue_nowait() to check if the bdev supports handling of
REQ_NOWAIT or not. Since then bio-based dm device can also support
REQ_NOWAIT, and currently only dm-linear supports that since
commit 6abc49468e ("dm: add support for REQ_NOWAIT and enable it for
linear target").

Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-19 07:32:36 -06:00
Minchan Kim 0726b01e70 mm/madvise: pass mm to do_madvise
Patch series "introduce memory hinting API for external process", v9.

Now, we have MADV_PAGEOUT and MADV_COLD as madvise hinting API.  With
that, application could give hints to kernel what memory range are
preferred to be reclaimed.  However, in some platform(e.g., Android), the
information required to make the hinting decision is not known to the app.
Instead, it is known to a centralized userspace daemon(e.g.,
ActivityManagerService), and that daemon must be able to initiate reclaim
on its own without any app involvement.

To solve the concern, this patch introduces new syscall -
process_madvise(2).  Bascially, it's same with madvise(2) syscall but it
has some differences.

1. It needs pidfd of target process to provide the hint

2. It supports only MADV_{COLD|PAGEOUT|MERGEABLE|UNMEREABLE} at this
   moment.  Other hints in madvise will be opened when there are explicit
   requests from community to prevent unexpected bugs we couldn't support.

3. Only privileged processes can do something for other process's
   address space.

For more detail of the new API, please see "mm: introduce external memory
hinting API" description in this patchset.

This patch (of 3):

In upcoming patches, do_madvise will be called from external process
context so we shouldn't asssume "current" is always hinted process's
task_struct.

Furthermore, we must not access mm_struct via task->mm, but obtain it via
access_mm() once (in the following patch) and only use that pointer [1],
so pass it to do_madvise() as well.  Note the vma->vm_mm pointers are
safe, so we can use them further down the call stack.

And let's pass current->mm as arguments of do_madvise so it shouldn't
change existing behavior but prepare next patch to make review easy.

[vbabka@suse.cz: changelog tweak]
[minchan@kernel.org: use current->mm for io_uring]
  Link: http://lkml.kernel.org/r/20200423145215.72666-1-minchan@kernel.org
[akpm@linux-foundation.org: fix it for upstream changes]
[akpm@linux-foundation.org: whoops]
[rdunlap@infradead.org: add missing includes]

Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jann Horn <jannh@google.com>
Cc: Tim Murray <timmurray@google.com>
Cc: Daniel Colascione <dancol@google.com>
Cc: Sandeep Patil <sspatil@google.com>
Cc: Sonny Rao <sonnyrao@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: John Dias <joaodias@google.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: SeongJae Park <sj38.park@gmail.com>
Cc: Christian Brauner <christian@brauner.io>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Oleksandr Natalenko <oleksandr@redhat.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Florian Weimer <fw@deneb.enyo.de>
Cc: <linux-man@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200901000633.1920247-1-minchan@kernel.org
Link: http://lkml.kernel.org/r/20200622192900.22757-1-minchan@kernel.org
Link: http://lkml.kernel.org/r/20200302193630.68771-2-minchan@kernel.org
Link: http://lkml.kernel.org/r/20200622192900.22757-2-minchan@kernel.org
Link: https://lkml.kernel.org/r/20200901000633.1920247-2-minchan@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-18 09:27:09 -07:00
Jens Axboe 91989c7078 task_work: cleanup notification modes
A previous commit changed the notification mode from true/false to an
int, allowing notify-no, notify-yes, or signal-notify. This was
backwards compatible in the sense that any existing true/false user
would translate to either 0 (on notification sent) or 1, the latter
which mapped to TWA_RESUME. TWA_SIGNAL was assigned a value of 2.

Clean this up properly, and define a proper enum for the notification
mode. Now we have:

- TWA_NONE. This is 0, same as before the original change, meaning no
  notification requested.
- TWA_RESUME. This is 1, same as before the original change, meaning
  that we use TIF_NOTIFY_RESUME.
- TWA_SIGNAL. This uses TIF_SIGPENDING/JOBCTL_TASK_WORK for the
  notification.

Clean up all the callers, switching their 0/1/false/true to using the
appropriate TWA_* mode for notifications.

Fixes: e91b481623 ("task_work: teach task_work_add() to do signal_wake_up()")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 15:05:30 -06:00
Pavel Begunkov 58852d4d67 io_uring: fix double poll mask init
__io_queue_proc() is used by both, poll reqs and apoll. Don't use
req->poll.events to copy poll mask because for apoll it aliases with
private data of the request.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:47 -06:00
Jens Axboe 4ea33a976b io-wq: inherit audit loginuid and sessionid
Make sure the async io-wq workers inherit the loginuid and sessionid from
the original task, and restore them to unset once we're done with the
async work item.

While at it, disable the ability for kernel threads to write to their own
loginuid.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:47 -06:00
Jens Axboe d8a6df10aa io_uring: use percpu counters to track inflight requests
Even though we place the req_issued and req_complete in separate
cachelines, there's considerable overhead in doing the atomics
particularly on the completion side.

Get rid of having the two counters, and just use a percpu_counter for
this. That's what it was made for, after all. This considerably
reduces the overhead in __io_free_req().

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:47 -06:00
Jens Axboe 500a373d73 io_uring: assign new io_identity for task if members have changed
This avoids doing a copy for each new async IO, if some parts of the
io_identity has changed. We avoid reference counting for the normal
fast path of nothing ever changing.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:46 -06:00
Jens Axboe 5c3462cfd1 io_uring: store io_identity in io_uring_task
This is, by definition, a per-task structure. So store it in the
task context, instead of doing carrying it in each io_kiocb. We're being
a bit inefficient if members have changed, as that requires an alloc and
copy of a new io_identity struct. The next patch will fix that up.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:46 -06:00
Jens Axboe 1e6fa5216a io_uring: COW io_identity on mismatch
If the io_identity doesn't completely match the task, then create a
copy of it and use that. The existing copy remains valid until the last
user of it has gone away.

This also changes the personality lookup to be indexed by io_identity,
instead of creds directly.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:46 -06:00
Jens Axboe 98447d65b4 io_uring: move io identity items into separate struct
io-wq contains a pointer to the identity, which we just hold in io_kiocb
for now. This is in preparation for putting this outside io_kiocb. The
only exception is struct files_struct, which we'll need different rules
for to avoid a circular dependency.

No functional changes in this patch.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:45 -06:00
Jens Axboe dfead8a8e2 io_uring: rely solely on work flags to determine personality.
We solely rely on work->work_flags now, so use that for proper checking
and clearing/dropping of various identity items.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:45 -06:00
Jens Axboe 0f20376588 io_uring: pass required context in as flags
We have a number of bits that decide what context to inherit. Set up
io-wq flags for these instead. This is in preparation for always having
the various members set, but not always needing them for all requests.

No intended functional changes in this patch.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:45 -06:00
Jens Axboe 55cbc2564a io_uring: fix error path cleanup in io_sqe_files_register()
syzbot reports the following crash:

general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 8927 Comm: syz-executor.3 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:io_file_from_index fs/io_uring.c:5963 [inline]
RIP: 0010:io_sqe_files_register fs/io_uring.c:7369 [inline]
RIP: 0010:__io_uring_register fs/io_uring.c:9463 [inline]
RIP: 0010:__do_sys_io_uring_register+0x2fd2/0x3ee0 fs/io_uring.c:9553
Code: ec 03 49 c1 ee 03 49 01 ec 49 01 ee e8 57 61 9c ff 41 80 3c 24 00 0f 85 9b 09 00 00 4d 8b af b8 01 00 00 4c 89 e8 48 c1 e8 03 <80> 3c 28 00 0f 85 76 09 00 00 49 8b 55 00 89 d8 c1 f8 09 48 98 4c
RSP: 0018:ffffc90009137d68 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9000ef2a000
RDX: 0000000000040000 RSI: ffffffff81d81dd9 RDI: 0000000000000005
RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffed1012882a37
R13: 0000000000000000 R14: ffffed1012882a38 R15: ffff888094415000
FS:  00007f4266f3c700(0000) GS:ffff8880ae500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000118c000 CR3: 000000008e57d000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45de59
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f4266f3bc78 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab
RAX: ffffffffffffffda RBX: 00000000000083c0 RCX: 000000000045de59
RDX: 0000000020000280 RSI: 0000000000000002 RDI: 0000000000000005
RBP: 000000000118bf68 R08: 0000000000000000 R09: 0000000000000000
R10: 40000000000000a1 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007fff2fa4f12f R14: 00007f4266f3c9c0 R15: 000000000118bf2c
Modules linked in:
---[ end trace 2a40a195e2d5e6e6 ]---
RIP: 0010:io_file_from_index fs/io_uring.c:5963 [inline]
RIP: 0010:io_sqe_files_register fs/io_uring.c:7369 [inline]
RIP: 0010:__io_uring_register fs/io_uring.c:9463 [inline]
RIP: 0010:__do_sys_io_uring_register+0x2fd2/0x3ee0 fs/io_uring.c:9553
Code: ec 03 49 c1 ee 03 49 01 ec 49 01 ee e8 57 61 9c ff 41 80 3c 24 00 0f 85 9b 09 00 00 4d 8b af b8 01 00 00 4c 89 e8 48 c1 e8 03 <80> 3c 28 00 0f 85 76 09 00 00 49 8b 55 00 89 d8 c1 f8 09 48 98 4c
RSP: 0018:ffffc90009137d68 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9000ef2a000
RDX: 0000000000040000 RSI: ffffffff81d81dd9 RDI: 0000000000000005
RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffed1012882a37
R13: 0000000000000000 R14: ffffed1012882a38 R15: ffff888094415000
FS:  00007f4266f3c700(0000) GS:ffff8880ae400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000074a918 CR3: 000000008e57d000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

which is a copy of fget failure condition jumping to cleanup, but the
cleanup requires ctx->file_data to be assigned. Assign it when setup,
and ensure that we clear it again for the error path exit.

Fixes: 5398ae6985 ("io_uring: clean file_data access in files_register")
Reported-by: syzbot+f4ebcc98223dafd8991e@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:44 -06:00
Jens Axboe 0918682be4 Revert "io_uring: mark io_uring_fops/io_op_defs as __read_mostly"
This reverts commit 738277adc8.

This change didn't make a lot of sense, and as Linus reports, it actually
fails on clang:

   /tmp/io_uring-dd40c4.s:26476: Warning: ignoring changed section
   attributes for .data..read_mostly

The arrays are already marked const so, by definition, they are not
just read-mostly, they are read-only.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:43 -06:00
Pavel Begunkov 216578e55a io_uring: fix REQ_F_COMP_LOCKED by killing it
REQ_F_COMP_LOCKED is used and implemented in a buggy way. The problem is
that the flag is set before io_put_req() but not cleared after, and if
that wasn't the final reference, the request will be freed with the flag
set from some other context, which may not hold a spinlock. That means
possible races with removing linked timeouts and unsynchronised
completion (e.g. access to CQ).

Instead of fixing REQ_F_COMP_LOCKED, kill the flag and use
task_work_add() to move such requests to a fresh context to free from
it, as was done with __io_free_req_finish().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:43 -06:00
Pavel Begunkov 4edf20f999 io_uring: dig out COMP_LOCK from deep call chain
io_req_clean_work() checks REQ_F_COMP_LOCK to pass this two layers up.
Move the check up into __io_free_req(), so at least it doesn't looks so
ugly and would facilitate further changes.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:43 -06:00
Pavel Begunkov 6a0af224c2 io_uring: don't put a poll req under spinlock
Move io_put_req() in io_poll_task_handler() from under spinlock. This
eliminates the need to use REQ_F_COMP_LOCKED, at the expense of
potentially having to grab the lock again. That's still a better trade
off than relying on the locked flag.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:42 -06:00
Pavel Begunkov b1b74cfc19 io_uring: don't unnecessarily clear F_LINK_TIMEOUT
If a request had REQ_F_LINK_TIMEOUT it would've been cleared in
__io_kill_linked_timeout() by the time of __io_fail_links(), so no need
to care about it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:42 -06:00
Pavel Begunkov 368c5481ae io_uring: don't set COMP_LOCKED if won't put
__io_kill_linked_timeout() sets REQ_F_COMP_LOCKED for a linked timeout
even if it can't cancel it, e.g. it's already running. It not only races
with io_link_timeout_fn() for ->flags field, but also leaves the flag
set and so io_link_timeout_fn() may find it and decide that it holds the
lock. Hopefully, the second problem is potential.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:42 -06:00
Colin Ian King 035fbafc7a io_uring: Fix sizeof() mismatch
An incorrect sizeof() is being used, sizeof(file_data->table) is not
correct, it should be sizeof(*file_data->table).

Fixes: 5398ae6985 ("io_uring: clean file_data access in files_register")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Addresses-Coverity: ("Sizeof not portable (SIZEOF_MISMATCH)")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-17 09:25:41 -06:00
Linus Torvalds 9ff9b0d392 networking changes for the 5.10 merge window
Add redirect_neigh() BPF packet redirect helper, allowing to limit stack
 traversal in common container configs and improving TCP back-pressure.
 Daniel reports ~10Gbps => ~15Gbps single stream TCP performance gain.
 
 Expand netlink policy support and improve policy export to user space.
 (Ge)netlink core performs request validation according to declared
 policies. Expand the expressiveness of those policies (min/max length
 and bitmasks). Allow dumping policies for particular commands.
 This is used for feature discovery by user space (instead of kernel
 version parsing or trial and error).
 
 Support IGMPv3/MLDv2 multicast listener discovery protocols in bridge.
 
 Allow more than 255 IPv4 multicast interfaces.
 
 Add support for Type of Service (ToS) reflection in SYN/SYN-ACK
 packets of TCPv6.
 
 In Multi-patch TCP (MPTCP) support concurrent transmission of data
 on multiple subflows in a load balancing scenario. Enhance advertising
 addresses via the RM_ADDR/ADD_ADDR options.
 
 Support SMC-Dv2 version of SMC, which enables multi-subnet deployments.
 
 Allow more calls to same peer in RxRPC.
 
 Support two new Controller Area Network (CAN) protocols -
 CAN-FD and ISO 15765-2:2016.
 
 Add xfrm/IPsec compat layer, solving the 32bit user space on 64bit
 kernel problem.
 
 Add TC actions for implementing MPLS L2 VPNs.
 
 Improve nexthop code - e.g. handle various corner cases when nexthop
 objects are removed from groups better, skip unnecessary notifications
 and make it easier to offload nexthops into HW by converting
 to a blocking notifier.
 
 Support adding and consuming TCP header options by BPF programs,
 opening the doors for easy experimental and deployment-specific
 TCP option use.
 
 Reorganize TCP congestion control (CC) initialization to simplify life
 of TCP CC implemented in BPF.
 
 Add support for shipping BPF programs with the kernel and loading them
 early on boot via the User Mode Driver mechanism, hence reusing all the
 user space infra we have.
 
 Support sleepable BPF programs, initially targeting LSM and tracing.
 
 Add bpf_d_path() helper for returning full path for given 'struct path'.
 
 Make bpf_tail_call compatible with bpf-to-bpf calls.
 
 Allow BPF programs to call map_update_elem on sockmaps.
 
 Add BPF Type Format (BTF) support for type and enum discovery, as
 well as support for using BTF within the kernel itself (current use
 is for pretty printing structures).
 
 Support listing and getting information about bpf_links via the bpf
 syscall.
 
 Enhance kernel interfaces around NIC firmware update. Allow specifying
 overwrite mask to control if settings etc. are reset during update;
 report expected max time operation may take to users; support firmware
 activation without machine reboot incl. limits of how much impact
 reset may have (e.g. dropping link or not).
 
 Extend ethtool configuration interface to report IEEE-standard
 counters, to limit the need for per-vendor logic in user space.
 
 Adopt or extend devlink use for debug, monitoring, fw update
 in many drivers (dsa loop, ice, ionic, sja1105, qed, mlxsw,
 mv88e6xxx, dpaa2-eth).
 
 In mlxsw expose critical and emergency SFP module temperature alarms.
 Refactor port buffer handling to make the defaults more suitable and
 support setting these values explicitly via the DCBNL interface.
 
 Add XDP support for Intel's igb driver.
 
 Support offloading TC flower classification and filtering rules to
 mscc_ocelot switches.
 
 Add PTP support for Marvell Octeontx2 and PP2.2 hardware, as well as
 fixed interval period pulse generator and one-step timestamping in
 dpaa-eth.
 
 Add support for various auth offloads in WiFi APs, e.g. SAE (WPA3)
 offload.
 
 Add Lynx PHY/PCS MDIO module, and convert various drivers which have
 this HW to use it. Convert mvpp2 to split PCS.
 
 Support Marvell Prestera 98DX3255 24-port switch ASICs, as well as
 7-port Mediatek MT7531 IP.
 
 Add initial support for QCA6390 and IPQ6018 in ath11k WiFi driver,
 and wcn3680 support in wcn36xx.
 
 Improve performance for packets which don't require much offloads
 on recent Mellanox NICs by 20% by making multiple packets share
 a descriptor entry.
 
 Move chelsio inline crypto drivers (for TLS and IPsec) from the crypto
 subtree to drivers/net. Move MDIO drivers out of the phy directory.
 
 Clean up a lot of W=1 warnings, reportedly the actively developed
 subsections of networking drivers should now build W=1 warning free.
 
 Make sure drivers don't use in_interrupt() to dynamically adapt their
 code. Convert tasklets to use new tasklet_setup API (sadly this
 conversion is not yet complete).
 
 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-next-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Jakub Kicinski:

 - Add redirect_neigh() BPF packet redirect helper, allowing to limit
   stack traversal in common container configs and improving TCP
   back-pressure.

   Daniel reports ~10Gbps => ~15Gbps single stream TCP performance gain.

 - Expand netlink policy support and improve policy export to user
   space. (Ge)netlink core performs request validation according to
   declared policies. Expand the expressiveness of those policies
   (min/max length and bitmasks). Allow dumping policies for particular
   commands. This is used for feature discovery by user space (instead
   of kernel version parsing or trial and error).

 - Support IGMPv3/MLDv2 multicast listener discovery protocols in
   bridge.

 - Allow more than 255 IPv4 multicast interfaces.

 - Add support for Type of Service (ToS) reflection in SYN/SYN-ACK
   packets of TCPv6.

 - In Multi-patch TCP (MPTCP) support concurrent transmission of data on
   multiple subflows in a load balancing scenario. Enhance advertising
   addresses via the RM_ADDR/ADD_ADDR options.

 - Support SMC-Dv2 version of SMC, which enables multi-subnet
   deployments.

 - Allow more calls to same peer in RxRPC.

 - Support two new Controller Area Network (CAN) protocols - CAN-FD and
   ISO 15765-2:2016.

 - Add xfrm/IPsec compat layer, solving the 32bit user space on 64bit
   kernel problem.

 - Add TC actions for implementing MPLS L2 VPNs.

 - Improve nexthop code - e.g. handle various corner cases when nexthop
   objects are removed from groups better, skip unnecessary
   notifications and make it easier to offload nexthops into HW by
   converting to a blocking notifier.

 - Support adding and consuming TCP header options by BPF programs,
   opening the doors for easy experimental and deployment-specific TCP
   option use.

 - Reorganize TCP congestion control (CC) initialization to simplify
   life of TCP CC implemented in BPF.

 - Add support for shipping BPF programs with the kernel and loading
   them early on boot via the User Mode Driver mechanism, hence reusing
   all the user space infra we have.

 - Support sleepable BPF programs, initially targeting LSM and tracing.

 - Add bpf_d_path() helper for returning full path for given 'struct
   path'.

 - Make bpf_tail_call compatible with bpf-to-bpf calls.

 - Allow BPF programs to call map_update_elem on sockmaps.

 - Add BPF Type Format (BTF) support for type and enum discovery, as
   well as support for using BTF within the kernel itself (current use
   is for pretty printing structures).

 - Support listing and getting information about bpf_links via the bpf
   syscall.

 - Enhance kernel interfaces around NIC firmware update. Allow
   specifying overwrite mask to control if settings etc. are reset
   during update; report expected max time operation may take to users;
   support firmware activation without machine reboot incl. limits of
   how much impact reset may have (e.g. dropping link or not).

 - Extend ethtool configuration interface to report IEEE-standard
   counters, to limit the need for per-vendor logic in user space.

 - Adopt or extend devlink use for debug, monitoring, fw update in many
   drivers (dsa loop, ice, ionic, sja1105, qed, mlxsw, mv88e6xxx,
   dpaa2-eth).

 - In mlxsw expose critical and emergency SFP module temperature alarms.
   Refactor port buffer handling to make the defaults more suitable and
   support setting these values explicitly via the DCBNL interface.

 - Add XDP support for Intel's igb driver.

 - Support offloading TC flower classification and filtering rules to
   mscc_ocelot switches.

 - Add PTP support for Marvell Octeontx2 and PP2.2 hardware, as well as
   fixed interval period pulse generator and one-step timestamping in
   dpaa-eth.

 - Add support for various auth offloads in WiFi APs, e.g. SAE (WPA3)
   offload.

 - Add Lynx PHY/PCS MDIO module, and convert various drivers which have
   this HW to use it. Convert mvpp2 to split PCS.

 - Support Marvell Prestera 98DX3255 24-port switch ASICs, as well as
   7-port Mediatek MT7531 IP.

 - Add initial support for QCA6390 and IPQ6018 in ath11k WiFi driver,
   and wcn3680 support in wcn36xx.

 - Improve performance for packets which don't require much offloads on
   recent Mellanox NICs by 20% by making multiple packets share a
   descriptor entry.

 - Move chelsio inline crypto drivers (for TLS and IPsec) from the
   crypto subtree to drivers/net. Move MDIO drivers out of the phy
   directory.

 - Clean up a lot of W=1 warnings, reportedly the actively developed
   subsections of networking drivers should now build W=1 warning free.

 - Make sure drivers don't use in_interrupt() to dynamically adapt their
   code. Convert tasklets to use new tasklet_setup API (sadly this
   conversion is not yet complete).

* tag 'net-next-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2583 commits)
  Revert "bpfilter: Fix build error with CONFIG_BPFILTER_UMH"
  net, sockmap: Don't call bpf_prog_put() on NULL pointer
  bpf, selftest: Fix flaky tcp_hdr_options test when adding addr to lo
  bpf, sockmap: Add locking annotations to iterator
  netfilter: nftables: allow re-computing sctp CRC-32C in 'payload' statements
  net: fix pos incrementment in ipv6_route_seq_next
  net/smc: fix invalid return code in smcd_new_buf_create()
  net/smc: fix valid DMBE buffer sizes
  net/smc: fix use-after-free of delayed events
  bpfilter: Fix build error with CONFIG_BPFILTER_UMH
  cxgb4/ch_ipsec: Replace the module name to ch_ipsec from chcr
  net: sched: Fix suspicious RCU usage while accessing tcf_tunnel_info
  bpf: Fix register equivalence tracking.
  rxrpc: Fix loss of final ack on shutdown
  rxrpc: Fix bundle counting for exclusive connections
  netfilter: restore NF_INET_NUMHOOKS
  ibmveth: Identify ingress large send packets.
  ibmveth: Switch order of ibmveth_helper calls.
  cxgb4: handle 4-tuple PEDIT to NAT mode translation
  selftests: Add VRF route leaking tests
  ...
2020-10-15 18:42:13 -07:00
Linus Torvalds 6ad4bf6ea1 io_uring-5.10-2020-10-12
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Merge tag 'io_uring-5.10-2020-10-12' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:

 - Add blkcg accounting for io-wq offload (Dennis)

 - A use-after-free fix for io-wq (Hillf)

 - Cancelation fixes and improvements

 - Use proper files_struct references for offload

 - Cleanup of io_uring_get_socket() since that can now go into our own
   header

 - SQPOLL fixes and cleanups, and support for sharing the thread

 - Improvement to how page accounting is done for registered buffers and
   huge pages, accounting the real pinned state

 - Series cleaning up the xarray code (Willy)

 - Various cleanups, refactoring, and improvements (Pavel)

 - Use raw spinlock for io-wq (Sebastian)

 - Add support for ring restrictions (Stefano)

* tag 'io_uring-5.10-2020-10-12' of git://git.kernel.dk/linux-block: (62 commits)
  io_uring: keep a pointer ref_node in file_data
  io_uring: refactor *files_register()'s error paths
  io_uring: clean file_data access in files_register
  io_uring: don't delay io_init_req() error check
  io_uring: clean leftovers after splitting issue
  io_uring: remove timeout.list after hrtimer cancel
  io_uring: use a separate struct for timeout_remove
  io_uring: improve submit_state.ios_left accounting
  io_uring: simplify io_file_get()
  io_uring: kill extra check in fixed io_file_get()
  io_uring: clean up ->files grabbing
  io_uring: don't io_prep_async_work() linked reqs
  io_uring: Convert advanced XArray uses to the normal API
  io_uring: Fix XArray usage in io_uring_add_task_file
  io_uring: Fix use of XArray in __io_uring_files_cancel
  io_uring: fix break condition for __io_uring_register() waiting
  io_uring: no need to call xa_destroy() on empty xarray
  io_uring: batch account ->req_issue and task struct references
  io_uring: kill callback_head argument for io_req_task_work_add()
  io_uring: move req preps out of io_issue_sqe()
  ...
2020-10-13 12:36:21 -07:00
Linus Torvalds 85ed13e78d Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull compat iovec cleanups from Al Viro:
 "Christoph's series around import_iovec() and compat variant thereof"

* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  security/keys: remove compat_keyctl_instantiate_key_iov
  mm: remove compat_process_vm_{readv,writev}
  fs: remove compat_sys_vmsplice
  fs: remove the compat readv/writev syscalls
  fs: remove various compat readv/writev helpers
  iov_iter: transparently handle compat iovecs in import_iovec
  iov_iter: refactor rw_copy_check_uvector and import_iovec
  iov_iter: move rw_copy_check_uvector() into lib/iov_iter.c
  compat.h: fix a spelling error in <linux/compat.h>
2020-10-12 16:35:51 -07:00
Pavel Begunkov b2e9685283 io_uring: keep a pointer ref_node in file_data
->cur_refs of struct fixed_file_data always points to percpu_ref
embedded into struct fixed_file_ref_node. Don't overuse container_of()
and offsetting, and point directly to fixed_file_ref_node.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-10 12:49:25 -06:00
Pavel Begunkov 600cf3f8b3 io_uring: refactor *files_register()'s error paths
Don't keep repeating cleaning sequences in error paths, write it once
in the and use labels. It's less error prone and looks cleaner.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-10 12:49:25 -06:00
Pavel Begunkov 5398ae6985 io_uring: clean file_data access in files_register
Keep file_data in a local var and replace with it complex references
such as ctx->file_data.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-10 12:49:25 -06:00
Pavel Begunkov 692d836351 io_uring: don't delay io_init_req() error check
Don't postpone io_init_req() error checks and do that right after
calling it. There is no control-flow statements or dependencies with
sqe/submitted accounting, so do those earlier, that makes the code flow
a bit more natural.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-10 12:49:25 -06:00
Pavel Begunkov 062d04d731 io_uring: clean leftovers after splitting issue
Kill extra if in io_issue_sqe() and place send/recv[msg] calls
appropriately under switch's cases.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-10 12:49:25 -06:00
Pavel Begunkov a71976f3fa io_uring: remove timeout.list after hrtimer cancel
Remove timeouts from ctx->timeout_list after hrtimer_try_to_cancel()
successfully cancels it. With this we don't need to care whether there
was a race and it was removed in io_timeout_fn(), and that will be handy
for following patches.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-10 12:49:25 -06:00
Pavel Begunkov 0bdf7a2ddb io_uring: use a separate struct for timeout_remove
Don't use struct io_timeout for both IORING_OP_TIMEOUT and
IORING_OP_TIMEOUT_REMOVE, they're quite different. Split them in two,
that allows to remove an unused field in struct io_timeout, and btw kill
->flags not used by either. This also easier to follow, especially for
timeout remove.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-10 12:49:25 -06:00
Pavel Begunkov 71b547c048 io_uring: improve submit_state.ios_left accounting
state->ios_left isn't decremented for requests that don't need a file,
so it might be larger than number of SQEs left. That in some
circumstances makes us to grab more files that is needed so imposing
extra put.
Deaccount one ios_left for each request.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-10 12:49:25 -06:00
Pavel Begunkov 8371adf53c io_uring: simplify io_file_get()
Keep ->needs_file_no_error check out of io_file_get(), and let callers
handle it. It makes it more straightforward. Also, as the only error it
can hand back -EBADF, make it return a file or NULL.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-10 12:49:24 -06:00
Pavel Begunkov 479f517be5 io_uring: kill extra check in fixed io_file_get()
ctx->nr_user_files == 0 IFF ctx->file_data == NULL and there fixed files
are not used. Hence, verifying fds only against ctx->nr_user_files is
enough. Remove the other check from hot path.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-10 12:49:24 -06:00
Pavel Begunkov 233295130e io_uring: clean up ->files grabbing
Move work.files grabbing into io_prep_async_work() to all other work
resources initialisation. We don't need to keep it separately now, as
->ring_fd/file are gone. It also allows to not grab it when a request
is not going to io-wq.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-10 12:49:24 -06:00
Pavel Begunkov 5bf5e464f1 io_uring: don't io_prep_async_work() linked reqs
There is no real reason left for preparing io-wq work context for linked
requests in advance, remove it as this might become a bottleneck in some
cases.

Reported-by: Roman Gershman <romger@amazon.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-10 12:49:20 -06:00
Matthew Wilcox (Oracle) 5e2ed8c4f4 io_uring: Convert advanced XArray uses to the normal API
There are no bugs here that I've spotted, it's just easier to use the
normal API and there are no performance advantages to using the more
verbose advanced API.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-09 09:00:05 -06:00
Matthew Wilcox (Oracle) 236434c343 io_uring: Fix XArray usage in io_uring_add_task_file
The xas_store() wasn't paired with an xas_nomem() loop, so if it couldn't
allocate memory using GFP_NOWAIT, it would leak the reference to the file
descriptor.  Also the node pointed to by the xas could be freed between
the call to xas_load() under the rcu_read_lock() and the acquisition of
the xa_lock.

It's easier to just use the normal xa_load/xa_store interface here.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
[axboe: fix missing assign after alloc, cur_uring -> tctx rename]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-09 08:59:40 -06:00
Matthew Wilcox (Oracle) ce765372bc io_uring: Fix use of XArray in __io_uring_files_cancel
We have to drop the lock during each iteration, so there's no advantage
to using the advanced API.  Convert this to a standard xa_for_each() loop.

Reported-by: syzbot+27c12725d8ff0bfe1a13@syzkaller.appspotmail.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-09 08:52:26 -06:00
Jens Axboe ed6930c920 io_uring: fix break condition for __io_uring_register() waiting
Colin reports that there's unreachable code, since we only ever break
if ret == 0. This is correct, and is due to a reversed logic condition
in when to break or not.

Break out of the loop if we don't process any task work, in that case
we do want to return -EINTR.

Fixes: af9c1a44f8 ("io_uring: process task work in io_uring_register()")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-08 20:37:45 -06:00
Jens Axboe ca6484cd30 io_uring: no need to call xa_destroy() on empty xarray
The kernel test robot reports this lockdep issue:

[child1:659] mbind (274) returned ENOSYS, marking as inactive.
[child1:659] mq_timedsend (279) returned ENOSYS, marking as inactive.
[main] 10175 iterations. [F:7781 S:2344 HI:2397]
[   24.610601]
[   24.610743] ================================
[   24.611083] WARNING: inconsistent lock state
[   24.611437] 5.9.0-rc7-00017-g0f2122045b9462 #5 Not tainted
[   24.611861] --------------------------------
[   24.612193] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[   24.612660] ksoftirqd/0/7 [HC0[0]:SC1[3]:HE0:SE0] takes:
[   24.613086] f00ed998 (&xa->xa_lock#4){+.?.}-{2:2}, at: xa_destroy+0x43/0xc1
[   24.613642] {SOFTIRQ-ON-W} state was registered at:
[   24.614024]   lock_acquire+0x20c/0x29b
[   24.614341]   _raw_spin_lock+0x21/0x30
[   24.614636]   io_uring_add_task_file+0xe8/0x13a
[   24.614987]   io_uring_create+0x535/0x6bd
[   24.615297]   io_uring_setup+0x11d/0x136
[   24.615606]   __ia32_sys_io_uring_setup+0xd/0xf
[   24.615977]   do_int80_syscall_32+0x53/0x6c
[   24.616306]   restore_all_switch_stack+0x0/0xb1
[   24.616677] irq event stamp: 939881
[   24.616968] hardirqs last  enabled at (939880): [<8105592d>] __local_bh_enable_ip+0x13c/0x145
[   24.617642] hardirqs last disabled at (939881): [<81b6ace3>] _raw_spin_lock_irqsave+0x1b/0x4e
[   24.618321] softirqs last  enabled at (939738): [<81b6c7c8>] __do_softirq+0x3f0/0x45a
[   24.618924] softirqs last disabled at (939743): [<81055741>] run_ksoftirqd+0x35/0x61
[   24.619521]
[   24.619521] other info that might help us debug this:
[   24.620028]  Possible unsafe locking scenario:
[   24.620028]
[   24.620492]        CPU0
[   24.620685]        ----
[   24.620894]   lock(&xa->xa_lock#4);
[   24.621168]   <Interrupt>
[   24.621381]     lock(&xa->xa_lock#4);
[   24.621695]
[   24.621695]  *** DEADLOCK ***
[   24.621695]
[   24.622154] 1 lock held by ksoftirqd/0/7:
[   24.622468]  #0: 823bfb94 (rcu_callback){....}-{0:0}, at: rcu_process_callbacks+0xc0/0x155
[   24.623106]
[   24.623106] stack backtrace:
[   24.623454] CPU: 0 PID: 7 Comm: ksoftirqd/0 Not tainted 5.9.0-rc7-00017-g0f2122045b9462 #5
[   24.624090] Call Trace:
[   24.624284]  ? show_stack+0x40/0x46
[   24.624551]  dump_stack+0x1b/0x1d
[   24.624809]  print_usage_bug+0x17a/0x185
[   24.625142]  mark_lock+0x11d/0x1db
[   24.625474]  ? print_shortest_lock_dependencies+0x121/0x121
[   24.625905]  __lock_acquire+0x41e/0x7bf
[   24.626206]  lock_acquire+0x20c/0x29b
[   24.626517]  ? xa_destroy+0x43/0xc1
[   24.626810]  ? lock_acquire+0x20c/0x29b
[   24.627110]  _raw_spin_lock_irqsave+0x3e/0x4e
[   24.627450]  ? xa_destroy+0x43/0xc1
[   24.627725]  xa_destroy+0x43/0xc1
[   24.627989]  __io_uring_free+0x57/0x71
[   24.628286]  ? get_pid+0x22/0x22
[   24.628544]  __put_task_struct+0xf2/0x163
[   24.628865]  put_task_struct+0x1f/0x2a
[   24.629161]  delayed_put_task_struct+0xe2/0xe9
[   24.629509]  rcu_process_callbacks+0x128/0x155
[   24.629860]  __do_softirq+0x1a3/0x45a
[   24.630151]  run_ksoftirqd+0x35/0x61
[   24.630443]  smpboot_thread_fn+0x304/0x31a
[   24.630763]  kthread+0x124/0x139
[   24.631016]  ? sort_range+0x18/0x18
[   24.631290]  ? kthread_create_worker_on_cpu+0x17/0x17
[   24.631682]  ret_from_fork+0x1c/0x28

which is complaining about xa_destroy() grabbing the xa lock in an
IRQ disabling fashion, whereas the io_uring uses cases aren't interrupt
safe. This is really an xarray issue, since it should not assume the
lock type. But for our use case, since we know the xarray is empty at
this point, there's no need to actually call xa_destroy(). So just get
rid of it.

Fixes: 0f2122045b ("io_uring: don't rely on weak ->files references")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-08 07:46:52 -06:00
Jens Axboe faf7b51c06 io_uring: batch account ->req_issue and task struct references
Identical to how we handle the ctx reference counts, increase by the
batch we're expecting to submit, and handle any slow path residual,
if any. The request alloc-and-issue path is very hot, and this makes
a noticeable difference by avoiding an two atomic incs for each
individual request.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-10-07 12:55:42 -06:00
David S. Miller 8b0308fe31 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Rejecting non-native endian BTF overlapped with the addition
of support for it.

The rest were more simple overlapping changes, except the
renesas ravb binding update, which had to follow a file
move as well as a YAML conversion.

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-10-05 18:40:01 -07:00
Christoph Hellwig 89cd35c58b iov_iter: transparently handle compat iovecs in import_iovec
Use in compat_syscall to import either native or the compat iovecs, and
remove the now superflous compat_import_iovec.

This removes the need for special compat logic in most callers, and
the remaining ones can still be simplified by using __import_iovec
with a bool compat parameter.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-10-03 00:02:13 -04:00
Linus Torvalds 702bfc891d io_uring-5.9-2020-10-02
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Merge tag 'io_uring-5.9-2020-10-02' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:

 - fix for async buffered reads if read-ahead is fully disabled (Hao)

 - double poll match fix

 - ->show_fdinfo() potential ABBA deadlock complaint fix

* tag 'io_uring-5.9-2020-10-02' of git://git.kernel.dk/linux-block:
  io_uring: fix async buffered reads when readahead is disabled
  io_uring: fix potential ABBA deadlock in ->show_fdinfo()
  io_uring: always delete double poll wait entry on match
2020-10-02 14:38:10 -07:00
Jens Axboe 87c4311fd2 io_uring: kill callback_head argument for io_req_task_work_add()
We always use &req->task_work anyway, no point in passing it in.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 21:00:16 -06:00
Pavel Begunkov c1379e247a io_uring: move req preps out of io_issue_sqe()
All request preparations are done only during submission, reflect it in
the code by moving io_req_prep() much earlier into io_queue_sqe().

That's much cleaner, because it doen't expose bits to async code which
it won't ever use. Also it makes the interface harder to misuse, and
there are potential places for bugs.

For instance, __io_queue() doesn't clear @sqe before proceeding to a
next linked request, that could have been disastrous, but hopefully
there are linked requests IFF sqe==NULL, so not actually a bug.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:38:46 -06:00
Pavel Begunkov bfe7655983 io_uring: decouple issuing and req preparation
io_issue_sqe() does two things at once, trying to prepare request and
issuing them. Split it in two and deduplicate with io_defer_prep().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:38:46 -06:00
Pavel Begunkov 73debe68b3 io_uring: remove nonblock arg from io_{rw}_prep()
All io_*_prep() functions including io_{read,write}_prep() are called
only during submission where @force_nonblock is always true. Don't keep
propagating it and instead remove the @force_nonblock argument
from prep() altogether.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:38:46 -06:00
Pavel Begunkov a88fc40021 io_uring: set/clear IOCB_NOWAIT into io_read/write
Move setting IOCB_NOWAIT from io_prep_rw() into io_read()/io_write(), so
it's set/cleared in a single place. Also remove @force_nonblock
parameter from io_prep_rw().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:38:46 -06:00
Pavel Begunkov 2d199895d2 io_uring: remove F_NEED_CLEANUP check in *prep()
REQ_F_NEED_CLEANUP is set only by io_*_prep() and they're guaranteed to
be called only once, so there is no one who may have set the flag
before. Kill REQ_F_NEED_CLEANUP check in these *prep() handlers.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:38:46 -06:00
Pavel Begunkov 5b09e37e27 io_uring: io_kiocb_ppos() style change
Put brackets around bitwise ops in a complex expression

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:38:45 -06:00
Pavel Begunkov 291b2821e0 io_uring: simplify io_alloc_req()
Extract common code from if/else branches. That is cleaner and optimised
even better.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:38:45 -06:00
Joseph Qi dbbe9c6424 io_uring: show sqthread pid and cpu in fdinfo
In most cases we'll specify IORING_SETUP_SQPOLL and run multiple
io_uring instances in a host. Since all sqthreads are named
"io_uring-sq", it's hard to distinguish the relations between
application process and its io_uring sqthread.
With this patch, application can get its corresponding sqthread pid
and cpu through show_fdinfo.
Steps:
1. Get io_uring fd first.
$ ls -l /proc/<pid>/fd | grep -w io_uring
2. Then get io_uring instance related info, including corresponding
sqthread pid and cpu.
$ cat /proc/<pid>/fdinfo/<io_uring_fd>

pos:	0
flags:	02000002
mnt_id:	13
SqThread:	6929
SqThreadCpu:	2
UserFiles:	1
    0: testfile
UserBufs:	0
PollList:

Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
[axboe: fixed for new shared SQPOLL]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Jens Axboe af9c1a44f8 io_uring: process task work in io_uring_register()
We do this for CQ ring wait, in case task_work completions come in. We
should do the same in io_uring_register(), to avoid spurious -EINTR
if the ring quiescing ends up having to process task_work to complete
the operation

Reported-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Dennis Zhou 91d8f5191e io_uring: add blkcg accounting to offloaded operations
There are a few operations that are offloaded to the worker threads. In
this case, we lose process context and end up in kthread context. This
results in ios to be not accounted to the issuing cgroup and
consequently end up as issued by root. Just like others, adopt the
personality of the blkcg too when issuing via the workqueues.

For the SQPOLL thread, it will live and attach in the inited cgroup's
context.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Jens Axboe de2939388b io_uring: improve registered buffer accounting for huge pages
io_uring does account any registered buffer as pinned/locked memory, and
checks limit and fails if the given user doesn't have a big enough limit
to register the ranges specified. However, if huge pages are used, we
are potentially under-accounting the memory in terms of what gets pinned
on the vm side.

This patch rectifies that, by ensuring that we account the full size of
a compound page, regardless of how much of it is being registered. Huge
pages are not accounted mulitple times - if multiple sections of a huge
page is registered, then the page is only accounted once.

Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Zheng Bin 14db84110d io_uring: remove unneeded semicolon
Fixes coccicheck warning:

fs/io_uring.c:4242:13-14: Unneeded semicolon

Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Jens Axboe e95eee2dee io_uring: cap SQ submit size for SQPOLL with multiple rings
In the spirit of fairness, cap the max number of SQ entries we'll submit
for SQPOLL if we have multiple rings. If we don't do that, we could be
submitting tons of entries for one ring, while others are waiting to get
service.

The value of 8 is somewhat arbitrarily chosen as something that allows
a fair bit of batching, without using an excessive time per ring.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Jens Axboe e8c2bc1fb6 io_uring: get rid of req->io/io_async_ctx union
There's really no point in having this union, it just means that we're
always allocating enough room to cater to any command. But that's
pointless, as the ->io field is request type private anyway.

This gets rid of the io_async_ctx structure, and fills in the required
size in the io_op_defs[] instead.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Pavel Begunkov 4be1c61512 io_uring: kill extra user_bufs check
Testing ctx->user_bufs for NULL in io_import_fixed() is not neccessary,
because in that case ctx->nr_user_bufs would be zero, and the following
check would fail.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:34 -06:00
Pavel Begunkov ab0b196ce5 io_uring: fix overlapped memcpy in io_req_map_rw()
When io_req_map_rw() is called from io_rw_prep_async(), it memcpy()
iorw->iter into itself. Even though it doesn't lead to an error, such a
memcpy()'s aliasing rules violation is considered to be a bad practise.

Inline io_req_map_rw() into io_rw_prep_async(). We don't really need any
remapping there, so it's much simpler than the generic implementation.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Pavel Begunkov afb87658f8 io_uring: refactor io_req_map_rw()
Set rw->free_iovec to @iovec, that gives an identical result and stresses
that @iovec param rw->free_iovec play the same role.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Pavel Begunkov f4bff104ff io_uring: simplify io_rw_prep_async()
Don't touch iter->iov and iov in between __io_import_iovec() and
io_req_map_rw(), the former function aleady sets it correctly, because it
creates one more case with NULL'ed iov to consider in io_req_map_rw().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe 9055420072 io_uring: provide IORING_ENTER_SQ_WAIT for SQPOLL SQ ring waits
When using SQPOLL, applications can run into the issue of running out of
SQ ring entries because the thread hasn't consumed them yet. The only
option for dealing with that is checking later, or busy checking for the
condition.

Provide IORING_ENTER_SQ_WAIT if applications want to wait on this
condition.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe 738277adc8 io_uring: mark io_uring_fops/io_op_defs as __read_mostly
These structures are never written, move them appropriately.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe aa06165de8 io_uring: enable IORING_SETUP_ATTACH_WQ to attach to SQPOLL thread too
We support using IORING_SETUP_ATTACH_WQ to share async backends between
rings created by the same process, this now also allows the same to
happen with SQPOLL. The setup procedure remains the same, the caller
sets io_uring_params->wq_fd to the 'parent' context, and then the newly
created ring will attach to that async backend.

This means that multiple rings can share the same SQPOLL thread, saving
resources.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe 69fb21310f io_uring: base SQPOLL handling off io_sq_data
Remove the SQPOLL thread from the ctx, and use the io_sq_data as the
data structure we pass in. io_sq_data has a list of ctx's that we can
then iterate over and handle.

As of now we're ready to handle multiple ctx's, though we're still just
handling a single one after this patch.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe 534ca6d684 io_uring: split SQPOLL data into separate structure
Move all the necessary state out of io_ring_ctx, and into a new
structure, io_sq_data. The latter now deals with any state or
variables associated with the SQPOLL thread itself.

In preparation for supporting more than one io_ring_ctx per SQPOLL
thread.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe c8d1ba583f io_uring: split work handling part of SQPOLL into helper
This is done in preparation for handling more than one ctx, but it also
cleans up the code a bit since io_sq_thread() was a bit too unwieldy to
get a get overview on.

__io_sq_thread() is now the main handler, and it returns an enum sq_ret
that tells io_sq_thread() what it ended up doing. The parent then makes
a decision on idle, spinning, or work handling based on that.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe 3f0e64d054 io_uring: move SQPOLL post-wakeup ring need wakeup flag into wake handler
We need to decouple the clearing on wakeup from the the inline schedule,
as that is going to be required for handling multiple rings in one
thread.

Wrap our wakeup handler so we can clear it when we get the wakeup, by
definition that is when we no longer need the flag set.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe 6a7793828f io_uring: use private ctx wait queue entries for SQPOLL
This is in preparation to sharing the poller thread between rings. For
that we need per-ring wait_queue_entry storage, and we can't easily put
that on the stack if one thread is managing multiple rings.

We'll also be sharing the wait_queue_head across rings for the purposes
of wakeups, provide the usual private ring wait_queue_head for now but
make it a pointer so we can easily override it when sharing.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe e35afcf912 io_uring: io_sq_thread() doesn't need to flush signals
We're not handling signals by default in kernel threads, and we never
use TWA_SIGNAL for the SQPOLL thread internally. Hence we can never
have a signal pending, and we don't need to check for it (nor flush it).

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Stefano Garzarella 7e84e1c756 io_uring: allow disabling rings during the creation
This patch adds a new IORING_SETUP_R_DISABLED flag to start the
rings disabled, allowing the user to register restrictions,
buffers, files, before to start processing SQEs.

When IORING_SETUP_R_DISABLED is set, SQE are not processed and
SQPOLL kthread is not started.

The restrictions registration are allowed only when the rings
are disable to prevent concurrency issue while processing SQEs.

The rings can be enabled using IORING_REGISTER_ENABLE_RINGS
opcode with io_uring_register(2).

Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Stefano Garzarella 21b55dbc06 io_uring: add IOURING_REGISTER_RESTRICTIONS opcode
The new io_uring_register(2) IOURING_REGISTER_RESTRICTIONS opcode
permanently installs a feature allowlist on an io_ring_ctx.
The io_ring_ctx can then be passed to untrusted code with the
knowledge that only operations present in the allowlist can be
executed.

The allowlist approach ensures that new features added to io_uring
do not accidentally become available when an existing application
is launched on a newer kernel version.

Currently is it possible to restrict sqe opcodes, sqe flags, and
register opcodes.

IOURING_REGISTER_RESTRICTIONS can only be made once. Afterwards
it is not possible to change restrictions anymore.
This prevents untrusted code from removing restrictions.

Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:33 -06:00
Jens Axboe 9b82849215 io_uring: reference ->nsproxy for file table commands
If we don't get and assign the namespace for the async work, then certain
paths just don't work properly (like /dev/stdin, /proc/mounts, etc).
Anything that references the current namespace of the given task should
be assigned for async work on behalf of that task.

Cc: stable@vger.kernel.org # v5.5+
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe 0f2122045b io_uring: don't rely on weak ->files references
Grab actual references to the files_struct. To avoid circular references
issues due to this, we add a per-task note that keeps track of what
io_uring contexts a task has used. When the tasks execs or exits its
assigned files, we cancel requests based on this tracking.

With that, we can grab proper references to the files table, and no
longer need to rely on stashing away ring_fd and ring_file to check
if the ring_fd may have been closed.

Cc: stable@vger.kernel.org # v5.5+
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe e6c8aa9ac3 io_uring: enable task/files specific overflow flushing
This allows us to selectively flush out pending overflows, depending on
the task and/or files_struct being passed in.

No intended functional changes in this patch.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe 76e1b6427f io_uring: return cancelation status from poll/timeout/files handlers
Return whether we found and canceled requests or not. This is in
preparation for using this information, no functional changes in this
patch.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe e3bc8e9dad io_uring: unconditionally grab req->task
Sometimes we assign a weak reference to it, sometimes we grab a
reference to it. Clean this up and make it unconditional, and drop the
flag related to tracking this state.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe 2aede0e417 io_uring: stash ctx task reference for SQPOLL
We can grab a reference to the task instead of stashing away the task
files_struct. This is doable without creating a circular reference
between the ring fd and the task itself.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe f573d38445 io_uring: move dropping of files into separate helper
No functional changes in this patch, prep patch for grabbing references
to the files_struct.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe f3606e3a92 io_uring: allow timeout/poll/files killing to take task into account
We currently cancel these when the ring exits, and we cancel all of
them. This is in preparation for killing only the ones associated
with a given task.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-30 20:32:32 -06:00
Jens Axboe 0f07889691 Merge branch 'io_uring-5.9' into for-5.10/io_uring
* io_uring-5.9:
  io_uring: fix async buffered reads when readahead is disabled
  io_uring: fix potential ABBA deadlock in ->show_fdinfo()
  io_uring: always delete double poll wait entry on match
2020-09-30 20:32:25 -06:00
Hao Xu c8d317aa18 io_uring: fix async buffered reads when readahead is disabled
The async buffered reads feature is not working when readahead is
turned off. There are two things to concern:

- when doing retry in io_read, not only the IOCB_WAITQ flag but also
  the IOCB_NOWAIT flag is still set, which makes it goes to would_block
  phase in generic_file_buffered_read() and then return -EAGAIN. After
  that, the io-wq thread work is queued, and later doing the async
  reads in the old way.

- even if we remove IOCB_NOWAIT when doing retry, the feature is still
  not running properly, since in generic_file_buffered_read() it goes to
  lock_page_killable() after calling mapping->a_ops->readpage() to do
  IO, and thus causing process to sleep.

Fixes: 1a0a7853b9 ("mm: support async buffered reads in generic_file_buffered_read()")
Fixes: 3b2a4439e0 ("io_uring: get rid of kiocb_wait_page_queue_init()")
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-29 07:54:00 -06:00
Jens Axboe fad8e0de44 io_uring: fix potential ABBA deadlock in ->show_fdinfo()
syzbot reports a potential lock deadlock between the normal IO path and
->show_fdinfo():

======================================================
WARNING: possible circular locking dependency detected
5.9.0-rc6-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.2/19710 is trying to acquire lock:
ffff888098ddc450 (sb_writers#4){.+.+}-{0:0}, at: io_write+0x6b5/0xb30 fs/io_uring.c:3296

but task is already holding lock:
ffff8880a11b8428 (&ctx->uring_lock){+.+.}-{3:3}, at: __do_sys_io_uring_enter+0xe9a/0x1bd0 fs/io_uring.c:8348

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (&ctx->uring_lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:956 [inline]
       __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
       __io_uring_show_fdinfo fs/io_uring.c:8417 [inline]
       io_uring_show_fdinfo+0x194/0xc70 fs/io_uring.c:8460
       seq_show+0x4a8/0x700 fs/proc/fd.c:65
       seq_read+0x432/0x1070 fs/seq_file.c:208
       do_loop_readv_writev fs/read_write.c:734 [inline]
       do_loop_readv_writev fs/read_write.c:721 [inline]
       do_iter_read+0x48e/0x6e0 fs/read_write.c:955
       vfs_readv+0xe5/0x150 fs/read_write.c:1073
       kernel_readv fs/splice.c:355 [inline]
       default_file_splice_read.constprop.0+0x4e6/0x9e0 fs/splice.c:412
       do_splice_to+0x137/0x170 fs/splice.c:871
       splice_direct_to_actor+0x307/0x980 fs/splice.c:950
       do_splice_direct+0x1b3/0x280 fs/splice.c:1059
       do_sendfile+0x55f/0xd40 fs/read_write.c:1540
       __do_sys_sendfile64 fs/read_write.c:1601 [inline]
       __se_sys_sendfile64 fs/read_write.c:1587 [inline]
       __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1587
       do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #1 (&p->lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:956 [inline]
       __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
       seq_read+0x61/0x1070 fs/seq_file.c:155
       pde_read fs/proc/inode.c:306 [inline]
       proc_reg_read+0x221/0x300 fs/proc/inode.c:318
       do_loop_readv_writev fs/read_write.c:734 [inline]
       do_loop_readv_writev fs/read_write.c:721 [inline]
       do_iter_read+0x48e/0x6e0 fs/read_write.c:955
       vfs_readv+0xe5/0x150 fs/read_write.c:1073
       kernel_readv fs/splice.c:355 [inline]
       default_file_splice_read.constprop.0+0x4e6/0x9e0 fs/splice.c:412
       do_splice_to+0x137/0x170 fs/splice.c:871
       splice_direct_to_actor+0x307/0x980 fs/splice.c:950
       do_splice_direct+0x1b3/0x280 fs/splice.c:1059
       do_sendfile+0x55f/0xd40 fs/read_write.c:1540
       __do_sys_sendfile64 fs/read_write.c:1601 [inline]
       __se_sys_sendfile64 fs/read_write.c:1587 [inline]
       __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1587
       do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #0 (sb_writers#4){.+.+}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:2496 [inline]
       check_prevs_add kernel/locking/lockdep.c:2601 [inline]
       validate_chain kernel/locking/lockdep.c:3218 [inline]
       __lock_acquire+0x2a96/0x5780 kernel/locking/lockdep.c:4441
       lock_acquire+0x1f3/0xaf0 kernel/locking/lockdep.c:5029
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write+0x228/0x450 fs/super.c:1672
       io_write+0x6b5/0xb30 fs/io_uring.c:3296
       io_issue_sqe+0x18f/0x5c50 fs/io_uring.c:5719
       __io_queue_sqe+0x280/0x1160 fs/io_uring.c:6175
       io_queue_sqe+0x692/0xfa0 fs/io_uring.c:6254
       io_submit_sqe fs/io_uring.c:6324 [inline]
       io_submit_sqes+0x1761/0x2400 fs/io_uring.c:6521
       __do_sys_io_uring_enter+0xeac/0x1bd0 fs/io_uring.c:8349
       do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

other info that might help us debug this:

Chain exists of:
  sb_writers#4 --> &p->lock --> &ctx->uring_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ctx->uring_lock);
                               lock(&p->lock);
                               lock(&ctx->uring_lock);
  lock(sb_writers#4);

 *** DEADLOCK ***

1 lock held by syz-executor.2/19710:
 #0: ffff8880a11b8428 (&ctx->uring_lock){+.+.}-{3:3}, at: __do_sys_io_uring_enter+0xe9a/0x1bd0 fs/io_uring.c:8348

stack backtrace:
CPU: 0 PID: 19710 Comm: syz-executor.2 Not tainted 5.9.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x198/0x1fd lib/dump_stack.c:118
 check_noncircular+0x324/0x3e0 kernel/locking/lockdep.c:1827
 check_prev_add kernel/locking/lockdep.c:2496 [inline]
 check_prevs_add kernel/locking/lockdep.c:2601 [inline]
 validate_chain kernel/locking/lockdep.c:3218 [inline]
 __lock_acquire+0x2a96/0x5780 kernel/locking/lockdep.c:4441
 lock_acquire+0x1f3/0xaf0 kernel/locking/lockdep.c:5029
 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
 __sb_start_write+0x228/0x450 fs/super.c:1672
 io_write+0x6b5/0xb30 fs/io_uring.c:3296
 io_issue_sqe+0x18f/0x5c50 fs/io_uring.c:5719
 __io_queue_sqe+0x280/0x1160 fs/io_uring.c:6175
 io_queue_sqe+0x692/0xfa0 fs/io_uring.c:6254
 io_submit_sqe fs/io_uring.c:6324 [inline]
 io_submit_sqes+0x1761/0x2400 fs/io_uring.c:6521
 __do_sys_io_uring_enter+0xeac/0x1bd0 fs/io_uring.c:8349
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e179
Code: 3d b2 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 0b b2 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f1194e74c78 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 00000000000082c0 RCX: 000000000045e179
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000004
RBP: 000000000118cf98 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffd1aa5756f R14: 00007f1194e759c0 R15: 000000000118cf4c

Fix this by just not diving into details if we fail to trylock the
io_uring mutex. We know the ctx isn't going away during this operation,
but we cannot safely iterate buffers/files/personalities if we don't
hold the io_uring mutex.

Reported-by: syzbot+2f8fa4e860edc3066aba@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-28 09:06:08 -06:00
Jens Axboe 8706e04ed7 io_uring: always delete double poll wait entry on match
syzbot reports a crash with tty polling, which is using the double poll
handling:

general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f]
CPU: 0 PID: 6874 Comm: syz-executor749 Not tainted 5.9.0-rc6-next-20200924-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:io_poll_get_single fs/io_uring.c:4778 [inline]
RIP: 0010:io_poll_double_wake+0x51/0x510 fs/io_uring.c:4845
Code: fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 9e 03 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 5d 08 48 8d 7b 48 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 63 03 00 00 0f b6 6b 48 bf 06 00 00
RSP: 0018:ffffc90001c1fb70 EFLAGS: 00010006
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000004
RDX: 0000000000000009 RSI: ffffffff81d9b3ad RDI: 0000000000000048
RBP: dffffc0000000000 R08: ffff8880a3cac798 R09: ffffc90001c1fc60
R10: fffff52000383f73 R11: 0000000000000000 R12: 0000000000000004
R13: ffff8880a3cac798 R14: ffff8880a3cac7a0 R15: 0000000000000004
FS:  0000000001f98880(0000) GS:ffff8880ae400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f18886916c0 CR3: 0000000094c5a000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __wake_up_common+0x147/0x650 kernel/sched/wait.c:93
 __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:123
 tty_ldisc_hangup+0x1cf/0x680 drivers/tty/tty_ldisc.c:735
 __tty_hangup.part.0+0x403/0x870 drivers/tty/tty_io.c:625
 __tty_hangup drivers/tty/tty_io.c:575 [inline]
 tty_vhangup+0x1d/0x30 drivers/tty/tty_io.c:698
 pty_close+0x3f5/0x550 drivers/tty/pty.c:79
 tty_release+0x455/0xf60 drivers/tty/tty_io.c:1679
 __fput+0x285/0x920 fs/file_table.c:281
 task_work_run+0xdd/0x190 kernel/task_work.c:141
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:165 [inline]
 exit_to_user_mode_prepare+0x1e2/0x1f0 kernel/entry/common.c:192
 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:267
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x401210

which is due to a failure in removing the double poll wait entry if we
hit a wakeup match. This can cause multiple invocations of the wakeup,
which isn't safe.

Cc: stable@vger.kernel.org # v5.8
Reported-by: syzbot+81b3883093f772addf6d@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-28 08:38:54 -06:00
Linus Torvalds 692495baa3 io_uring-5.9-2020-09-25
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Merge tag 'io_uring-5.9-2020-09-25' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:
 "Two fixes for regressions in this cycle, and one that goes to 5.8
  stable:

   - fix leak of getname() retrieved filename

   - remove plug->nowait assignment, fixing a regression with btrfs

   - fix for async buffered retry"

* tag 'io_uring-5.9-2020-09-25' of git://git.kernel.dk/linux-block:
  io_uring: ensure async buffered read-retry is setup properly
  io_uring: don't unconditionally set plug->nowait = true
  io_uring: ensure open/openat2 name is cleaned on cancelation
2020-09-26 11:13:51 -07:00
Jens Axboe f38c7e3abf io_uring: ensure async buffered read-retry is setup properly
A previous commit for fixing up short reads botched the async retry
path, so we ended up going to worker threads more often than we should.
Fix this up, so retries work the way they originally were intended to.

Fixes: 227c0c9673 ("io_uring: internally retry short reads")
Reported-by: Hao_Xu <haoxu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-25 15:39:13 -06:00
Jens Axboe 62c774ed48 io_uring: don't unconditionally set plug->nowait = true
This causes all the bios to be submitted with REQ_NOWAIT, which can be
problematic on either btrfs or on file systems that otherwise use a mix
of block devices where only some of them support it.

For now, just remove the setting of plug->nowait = true.

Reported-by: Dan Melnic <dmm@fb.com>
Reported-by: Brian Foster <bfoster@redhat.com>
Fixes: b63534c41e ("io_uring: re-issue block requests that failed because of resources")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-25 09:01:53 -06:00
Jens Axboe f3cd485050 io_uring: ensure open/openat2 name is cleaned on cancelation
If we cancel these requests, we'll leak the memory associated with the
filename. Add them to the table of ops that need cleaning, if
REQ_F_NEED_CLEANUP is set.

Cc: stable@vger.kernel.org
Fixes: e62753e4e2 ("io_uring: call statx directly")
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-25 07:41:46 -06:00
David S. Miller 3ab0a7a0c3 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Two minor conflicts:

1) net/ipv4/route.c, adding a new local variable while
   moving another local variable and removing it's
   initial assignment.

2) drivers/net/dsa/microchip/ksz9477.c, overlapping changes.
   One pretty prints the port mode differently, whilst another
   changes the driver to try and obtain the port mode from
   the port node rather than the switch node.

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-22 16:45:34 -07:00
Linus Torvalds 0baca07006 io_uring-5.9-2020-09-22
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Merge tag 'io_uring-5.9-2020-09-22' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:
 "A few fixes - most of them regression fixes from this cycle, but also
  a few stable heading fixes, and a build fix for the included demo tool
  since some systems now actually have gettid() available"

* tag 'io_uring-5.9-2020-09-22' of git://git.kernel.dk/linux-block:
  io_uring: fix openat/openat2 unified prep handling
  io_uring: mark statx/files_update/epoll_ctl as non-SQPOLL
  tools/io_uring: fix compile breakage
  io_uring: don't use retry based buffered reads for non-async bdev
  io_uring: don't re-setup vecs/iter in io_resumit_prep() is already there
  io_uring: don't run task work on an exiting task
  io_uring: drop 'ctx' ref on task work cancelation
  io_uring: grab any needed state during defer prep
2020-09-22 14:36:50 -07:00