Commit Graph

43142 Commits

Author SHA1 Message Date
John Stultz 448a2500d1 sched: Move psi_account_irqtime() out of update_rq_clock_task() hotpath
commit ddae0ca2a8fe12d0e24ab10ba759c3fbd755ada8 upstream.

It was reported that in moving to 6.1, a larger then 10%
regression was seen in the performance of
clock_gettime(CLOCK_THREAD_CPUTIME_ID,...).

Using a simple reproducer, I found:
5.10:
100000000 calls in 24345994193 ns => 243.460 ns per call
100000000 calls in 24288172050 ns => 242.882 ns per call
100000000 calls in 24289135225 ns => 242.891 ns per call

6.1:
100000000 calls in 28248646742 ns => 282.486 ns per call
100000000 calls in 28227055067 ns => 282.271 ns per call
100000000 calls in 28177471287 ns => 281.775 ns per call

The cause of this was finally narrowed down to the addition of
psi_account_irqtime() in update_rq_clock_task(), in commit
52b1364ba0 ("sched/psi: Add PSI_IRQ to track IRQ/SOFTIRQ
pressure").

In my initial attempt to resolve this, I leaned towards moving
all accounting work out of the clock_gettime() call path, but it
wasn't very pretty, so it will have to wait for a later deeper
rework. Instead, Peter shared this approach:

Rework psi_account_irqtime() to use its own psi_irq_time base
for accounting, and move it out of the hotpath, calling it
instead from sched_tick() and __schedule().

In testing this, we found the importance of ensuring
psi_account_irqtime() is run under the rq_lock, which Johannes
Weiner helpfully explained, so also add some lockdep annotations
to make that requirement clear.

With this change the performance is back in-line with 5.10:
6.1+fix:
100000000 calls in 24297324597 ns => 242.973 ns per call
100000000 calls in 24318869234 ns => 243.189 ns per call
100000000 calls in 24291564588 ns => 242.916 ns per call

Reported-by: Jimmy Shiu <jimmyshiu@google.com>
Originally-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Reviewed-by: Qais Yousef <qyousef@layalina.io>
Link: https://lore.kernel.org/r/20240618215909.4099720-1-jstultz@google.com
Fixes: 52b1364ba0 ("sched/psi: Add PSI_IRQ to track IRQ/SOFTIRQ pressure")
[jstultz: Fixed up minor collisions w/ 6.6-stable]
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-18 13:21:25 +02:00
Josh Don 1e116c18e3 Revert "sched/fair: Make sure to try to detach at least one movable task"
commit 2feab2492deb2f14f9675dd6388e9e2bf669c27a upstream.

This reverts commit b0defa7ae0.

b0defa7ae0 changed the load balancing logic to ignore env.max_loop if
all tasks examined to that point were pinned. The goal of the patch was
to make it more likely to be able to detach a task buried in a long list
of pinned tasks. However, this has the unfortunate side effect of
creating an O(n) iteration in detach_tasks(), as we now must fully
iterate every task on a cpu if all or most are pinned. Since this load
balance code is done with rq lock held, and often in softirq context, it
is very easy to trigger hard lockups. We observed such hard lockups with
a user who affined O(10k) threads to a single cpu.

When I discussed this with Vincent he initially suggested that we keep
the limit on the number of tasks to detach, but increase the number of
tasks we can search. However, after some back and forth on the mailing
list, he recommended we instead revert the original patch, as it seems
likely no one was actually getting hit by the original issue.

Fixes: b0defa7ae0 ("sched/fair: Make sure to try to detach at least one movable task")
Signed-off-by: Josh Don <joshdon@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20240620214450.316280-1-joshdon@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-18 13:21:17 +02:00
Kumar Kartikeya Dwivedi 9369830518 bpf: Fail bpf_timer_cancel when callback is being cancelled
[ Upstream commit d4523831f07a267a943f0dde844bf8ead7495f13 ]

Given a schedule:

timer1 cb			timer2 cb

bpf_timer_cancel(timer2);	bpf_timer_cancel(timer1);

Both bpf_timer_cancel calls would wait for the other callback to finish
executing, introducing a lockup.

Add an atomic_t count named 'cancelling' in bpf_hrtimer. This keeps
track of all in-flight cancellation requests for a given BPF timer.
Whenever cancelling a BPF timer, we must check if we have outstanding
cancellation requests, and if so, we must fail the operation with an
error (-EDEADLK) since cancellation is synchronous and waits for the
callback to finish executing. This implies that we can enter a deadlock
situation involving two or more timer callbacks executing in parallel
and attempting to cancel one another.

Note that we avoid incrementing the cancelling counter for the target
timer (the one being cancelled) if bpf_timer_cancel is not invoked from
a callback, to avoid spurious errors. The whole point of detecting
cur->cancelling and returning -EDEADLK is to not enter a busy wait loop
(which may or may not lead to a lockup). This does not apply in case the
caller is in a non-callback context, the other side can continue to
cancel as it sees fit without running into errors.

Background on prior attempts:

Earlier versions of this patch used a bool 'cancelling' bit and used the
following pattern under timer->lock to publish cancellation status.

lock(t->lock);
t->cancelling = true;
mb();
if (cur->cancelling)
	return -EDEADLK;
unlock(t->lock);
hrtimer_cancel(t->timer);
t->cancelling = false;

The store outside the critical section could overwrite a parallel
requests t->cancelling assignment to true, to ensure the parallely
executing callback observes its cancellation status.

It would be necessary to clear this cancelling bit once hrtimer_cancel
is done, but lack of serialization introduced races. Another option was
explored where bpf_timer_start would clear the bit when (re)starting the
timer under timer->lock. This would ensure serialized access to the
cancelling bit, but may allow it to be cleared before in-flight
hrtimer_cancel has finished executing, such that lockups can occur
again.

Thus, we choose an atomic counter to keep track of all outstanding
cancellation requests and use it to prevent lockups in case callbacks
attempt to cancel each other while executing in parallel.

Reported-by: Dohyun Kim <dohyunkim@google.com>
Reported-by: Neel Natu <neelnatu@google.com>
Fixes: b00628b1c7 ("bpf: Introduce bpf timers.")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20240709185440.1104957-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-18 13:21:14 +02:00
Benjamin Tissoires e97c862e0b bpf: replace bpf_timer_init with a generic helper
[ Upstream commit 56b4a177ae6322173360a93ea828ad18570a5a14 ]

No code change except for the new flags argument being stored in the
local data struct.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-2-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: d4523831f07a ("bpf: Fail bpf_timer_cancel when callback is being cancelled")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-18 13:21:13 +02:00
Benjamin Tissoires 5910035674 bpf: make timer data struct more generic
[ Upstream commit be2749beff62e0d63cf97fe63cabc79a68443139 ]

To be able to add workqueues and reuse most of the timer code, we need
to make bpf_hrtimer more generic.

There is no code change except that the new struct gets a new u64 flags
attribute. We are still below 2 cache lines, so this shouldn't impact
the current running codes.

The ordering is also changed. Everything related to async callback
is now on top of bpf_hrtimer.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-1-6c986a5a741f@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: d4523831f07a ("bpf: Fail bpf_timer_cancel when callback is being cancelled")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-18 13:21:13 +02:00
Mohammad Shehar Yaar Tausif e65a49b948 bpf: fix order of args in call to bpf_map_kvcalloc
[ Upstream commit af253aef183a31ce62d2e39fc520b0ebfb562bb9 ]

The original function call passed size of smap->bucket before the number of
buckets which raises the error 'calloc-transposed-args' on compilation.

Vlastimil Babka added:

The order of parameters can be traced back all the way to 6ac99e8f23
("bpf: Introduce bpf sk local storage") accross several refactorings,
and that's why the commit is used as a Fixes: tag.

In v6.10-rc1, a different commit 2c321f3f70bc ("mm: change inlined
allocation helpers to account at the call site") however exposed the
order of args in a way that gcc-14 has enough visibility to start
warning about it, because (in !CONFIG_MEMCG case) bpf_map_kvcalloc is
then a macro alias for kvcalloc instead of a static inline wrapper.

To sum up the warning happens when the following conditions are all met:

- gcc-14 is used (didn't see it with gcc-13)
- commit 2c321f3f70bc is present
- CONFIG_MEMCG is not enabled in .config
- CONFIG_WERROR turns this from a compiler warning to error

Fixes: 6ac99e8f23 ("bpf: Introduce bpf sk local storage")
Reviewed-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Christian Kujau <lists@nerdbynature.de>
Signed-off-by: Mohammad Shehar Yaar Tausif <sheharyaar48@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Link: https://lore.kernel.org/r/20240710100521.15061-2-vbabka@suse.cz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-18 13:21:13 +02:00
Fedor Pchelkin 39d31edcf9 dma-mapping: benchmark: avoid needless copy_to_user if benchmark fails
[ Upstream commit f7c9ccaadffd13066353332c13d7e9bf73b8f92d ]

If do_map_benchmark() has failed, there is nothing useful to copy back
to userspace.

Suggested-by: Barry Song <21cnbao@gmail.com>
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-11 12:49:20 +02:00
GUO Zihua 28d0ecc52f ima: Avoid blocking in RCU read-side critical section
commit 9a95c5bfbf02a0a7f5983280fe284a0ff0836c34 upstream.

A panic happens in ima_match_policy:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
PGD 42f873067 P4D 0
Oops: 0000 [#1] SMP NOPTI
CPU: 5 PID: 1286325 Comm: kubeletmonit.sh
Kdump: loaded Tainted: P
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
               BIOS 0.0.0 02/06/2015
RIP: 0010:ima_match_policy+0x84/0x450
Code: 49 89 fc 41 89 cf 31 ed 89 44 24 14 eb 1c 44 39
      7b 18 74 26 41 83 ff 05 74 20 48 8b 1b 48 3b 1d
      f2 b9 f4 00 0f 84 9c 01 00 00 <44> 85 73 10 74 ea
      44 8b 6b 14 41 f6 c5 01 75 d4 41 f6 c5 02 74 0f
RSP: 0018:ff71570009e07a80 EFLAGS: 00010207
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000200
RDX: ffffffffad8dc7c0 RSI: 0000000024924925 RDI: ff3e27850dea2000
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffffabfce739
R10: ff3e27810cc42400 R11: 0000000000000000 R12: ff3e2781825ef970
R13: 00000000ff3e2785 R14: 000000000000000c R15: 0000000000000001
FS:  00007f5195b51740(0000)
GS:ff3e278b12d40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000010 CR3: 0000000626d24002 CR4: 0000000000361ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ima_get_action+0x22/0x30
 process_measurement+0xb0/0x830
 ? page_add_file_rmap+0x15/0x170
 ? alloc_set_pte+0x269/0x4c0
 ? prep_new_page+0x81/0x140
 ? simple_xattr_get+0x75/0xa0
 ? selinux_file_open+0x9d/0xf0
 ima_file_check+0x64/0x90
 path_openat+0x571/0x1720
 do_filp_open+0x9b/0x110
 ? page_counter_try_charge+0x57/0xc0
 ? files_cgroup_alloc_fd+0x38/0x60
 ? __alloc_fd+0xd4/0x250
 ? do_sys_open+0x1bd/0x250
 do_sys_open+0x1bd/0x250
 do_syscall_64+0x5d/0x1d0
 entry_SYSCALL_64_after_hwframe+0x65/0xca

Commit c7423dbdbc ("ima: Handle -ESTALE returned by
ima_filter_rule_match()") introduced call to ima_lsm_copy_rule within a
RCU read-side critical section which contains kmalloc with GFP_KERNEL.
This implies a possible sleep and violates limitations of RCU read-side
critical sections on non-PREEMPT systems.

Sleeping within RCU read-side critical section might cause
synchronize_rcu() returning early and break RCU protection, allowing a
UAF to happen.

The root cause of this issue could be described as follows:
|	Thread A	|	Thread B	|
|			|ima_match_policy	|
|			|  rcu_read_lock	|
|ima_lsm_update_rule	|			|
|  synchronize_rcu	|			|
|			|    kmalloc(GFP_KERNEL)|
|			|      sleep		|
==> synchronize_rcu returns early
|  kfree(entry)		|			|
|			|    entry = entry->next|
==> UAF happens and entry now becomes NULL (or could be anything).
|			|    entry->action	|
==> Accessing entry might cause panic.

To fix this issue, we are converting all kmalloc that is called within
RCU read-side critical section to use GFP_ATOMIC.

Fixes: c7423dbdbc ("ima: Handle -ESTALE returned by ima_filter_rule_match()")
Cc: stable@vger.kernel.org
Signed-off-by: GUO Zihua <guozihua@huawei.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: fixed missing comment, long lines, !CONFIG_IMA_LSM_RULES case]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-11 12:49:18 +02:00
Jinliang Zheng 79ad410c5b mm: optimize the redundant loop of mm_update_owner_next()
commit cf3f9a593dab87a032d2b6a6fb205e7f3de4f0a1 upstream.

When mm_update_owner_next() is racing with swapoff (try_to_unuse()) or
/proc or ptrace or page migration (get_task_mm()), it is impossible to
find an appropriate task_struct in the loop whose mm_struct is the same as
the target mm_struct.

If the above race condition is combined with the stress-ng-zombie and
stress-ng-dup tests, such a long loop can easily cause a Hard Lockup in
write_lock_irq() for tasklist_lock.

Recognize this situation in advance and exit early.

Link: https://lkml.kernel.org/r/20240620122123.3877432-1-alexjlzheng@tencent.com
Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tycho Andersen <tandersen@netflix.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-11 12:49:15 +02:00
Huacai Chen 69787793e7 cpu: Fix broken cmdline "nosmp" and "maxcpus=0"
commit 6ef8eb5125722c241fd60d7b0c872d5c2e5dd4ca upstream.

After the rework of "Parallel CPU bringup", the cmdline "nosmp" and
"maxcpus=0" parameters are not working anymore. These parameters set
setup_max_cpus to zero and that's handed to bringup_nonboot_cpus().

The code there does a decrement before checking for zero, which brings it
into the negative space and brings up all CPUs.

Add a zero check at the beginning of the function to prevent this.

[ tglx: Massaged change log ]

Fixes: 18415f33e2 ("cpu/hotplug: Allow "parallel" bringup up to CPUHP_BP_KICK_AP_STATE")
Fixes: 06c6796e03 ("cpu/hotplug: Fix off by one in cpuhp_bringup_mask()")
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240618081336.3996825-1-chenhuacai@loongson.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-11 12:49:14 +02:00
Mike Christie abe067dc3a vhost_task: Handle SIGKILL by flushing work and exiting
[ Upstream commit db5247d9bf5c6ade9fd70b4e4897441e0269b233 ]

Instead of lingering until the device is closed, this has us handle
SIGKILL by:

1. marking the worker as killed so we no longer try to use it with
   new virtqueues and new flush operations.
2. setting the virtqueue to worker mapping so no new works are queued.
3. running all the exiting works.

Suggested-by: Edward Adam Davis <eadavis@qq.com>
Reported-and-tested-by: syzbot+98edc2df894917b3431f@syzkaller.appspotmail.com
Message-Id: <tencent_546DA49414E876EEBECF2C78D26D242EE50A@qq.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20240316004707.45557-9-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-11 12:49:10 +02:00
George Stark 7d2a6abec0 locking/mutex: Introduce devm_mutex_init()
[ Upstream commit 4cd47222e435dec8e3787614924174f53fcfb5ae ]

Using of devm API leads to a certain order of releasing resources.
So all dependent resources which are not devm-wrapped should be deleted
with respect to devm-release order. Mutex is one of such objects that
often is bound to other resources and has no own devm wrapping.
Since mutex_destroy() actually does nothing in non-debug builds
frequently calling mutex_destroy() is just ignored which is safe for now
but wrong formally and can lead to a problem if mutex_destroy() will be
extended so introduce devm_mutex_init().

Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: George Stark <gnstark@salutedevices.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Marek Behún <kabel@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20240411161032.609544-2-gnstark@salutedevices.com
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-11 12:49:02 +02:00
Greg Kroah-Hartman e3540e5a70 Revert "bpf: Take return from set_memory_ro() into account with bpf_prog_lock_ro()"
This reverts commit fdd411af81 which is
commit 7d2cc63eca0c993c99d18893214abf8f85d566d8 upstream.

It is part of a series that is reported to both break the arm64 builds
and instantly crashes the powerpc systems at the first load of a bpf
program.  So revert it for now until it can come back in a safe way.

Reported-by: matoro <matoro_mailinglist_kernel@matoro.tk>
Reported-by: Vitaly Chikunov <vt@altlinux.org>
Reported-by: WangYuli <wangyuli@uniontech.com>
Link: https://lore.kernel.org/r/5A29E00D83AB84E3+20240706031101.637601-1-wangyuli@uniontech.com
Link: https://lore.kernel.org/r/cf736c5e37489e7dc7ffd67b9de2ab47@matoro.tk
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Song Liu <song@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Kees Cook <keescook@chromium.org>
Cc: Puranjay Mohan <puranjay12@gmail.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>  # s390x
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>  # LoongArch
Cc: Johan Almbladh <johan.almbladh@anyfinetworks.com> # MIPS Part
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-09 11:44:29 +02:00
Arnd Bergmann e04886b50c syscalls: fix compat_sys_io_pgetevents_time64 usage
commit d3882564a77c21eb746ba5364f3fa89b88de3d61 upstream.

Using sys_io_pgetevents() as the entry point for compat mode tasks
works almost correctly, but misses the sign extension for the min_nr
and nr arguments.

This was addressed on parisc by switching to
compat_sys_io_pgetevents_time64() in commit 6431e92fc8 ("parisc:
io_pgetevents_time64() needs compat syscall in 32-bit compat mode"),
as well as by using more sophisticated system call wrappers on x86 and
s390. However, arm64, mips, powerpc, sparc and riscv still have the
same bug.

Change all of them over to use compat_sys_io_pgetevents_time64()
like parisc already does. This was clearly the intention when the
function was originally added, but it got hooked up incorrectly in
the tables.

Cc: stable@vger.kernel.org
Fixes: 48166e6ea4 ("y2038: add 64-bit time_t syscalls to all 32-bit architectures")
Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-05 09:34:04 +02:00
Yuntao Wang 52bbae429b cpu/hotplug: Fix dynstate assignment in __cpuhp_setup_state_cpuslocked()
commit 932d8476399f622aa0767a4a0a9e78e5341dc0e1 upstream.

Commit 4205e4786d ("cpu/hotplug: Provide dynamic range for prepare
stage") added a dynamic range for the prepare states, but did not handle
the assignment of the dynstate variable in __cpuhp_setup_state_cpuslocked().

This causes the corresponding startup callback not to be invoked when
calling __cpuhp_setup_state_cpuslocked() with the CPUHP_BP_PREPARE_DYN
parameter, even though it should be.

Currently, the users of __cpuhp_setup_state_cpuslocked(), for one reason or
another, have not triggered this bug.

Fixes: 4205e4786d ("cpu/hotplug: Provide dynamic range for prepare stage")
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240515134554.427071-1-ytcoode@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-05 09:34:01 +02:00
Martin KaFai Lau d812ae6e02 bpf: Mark bpf prog stack with kmsan_unposion_memory in interpreter mode
[ Upstream commit e8742081db7d01f980c6161ae1e8a1dbc1e30979 ]

syzbot reported uninit memory usages during map_{lookup,delete}_elem.

==========
BUG: KMSAN: uninit-value in __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
BUG: KMSAN: uninit-value in dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
__dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline]
dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796
____bpf_map_lookup_elem kernel/bpf/helpers.c:42 [inline]
bpf_map_lookup_elem+0x5c/0x80 kernel/bpf/helpers.c:38
___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
__bpf_prog_run256+0xb5/0xe0 kernel/bpf/core.c:2237
==========

The reproducer should be in the interpreter mode.

The C reproducer is trying to run the following bpf prog:

    0: (18) r0 = 0x0
    2: (18) r1 = map[id:49]
    4: (b7) r8 = 16777216
    5: (7b) *(u64 *)(r10 -8) = r8
    6: (bf) r2 = r10
    7: (07) r2 += -229
            ^^^^^^^^^^

    8: (b7) r3 = 8
    9: (b7) r4 = 0
   10: (85) call dev_map_lookup_elem#1543472
   11: (95) exit

It is due to the "void *key" (r2) passed to the helper. bpf allows uninit
stack memory access for bpf prog with the right privileges. This patch
uses kmsan_unpoison_memory() to mark the stack as initialized.

This should address different syzbot reports on the uninit "void *key"
argument during map_{lookup,delete}_elem.

Reported-by: syzbot+603bcd9b0bf1d94dbb9b@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/000000000000f9ce6d061494e694@google.com/
Reported-by: syzbot+eb02dc7f03dce0ef39f3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/000000000000a5c69c06147c2238@google.com/
Reported-by: syzbot+b4e65ca24fd4d0c734c3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/000000000000ac56fb06143b6cfa@google.com/
Reported-by: syzbot+d2b113dc9fea5e1d2848@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/0000000000000d69b206142d1ff7@google.com/
Reported-by: syzbot+1a3cf6f08d68868f9db3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/0000000000006f876b061478e878@google.com/
Tested-by: syzbot+1a3cf6f08d68868f9db3@syzkaller.appspotmail.com
Suggested-by: Yonghong Song <yonghong.song@linux.dev>
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240328185801.1843078-1-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-05 09:33:51 +02:00
Christophe Leroy fdd411af81 bpf: Take return from set_memory_ro() into account with bpf_prog_lock_ro()
[ Upstream commit 7d2cc63eca0c993c99d18893214abf8f85d566d8 ]

set_memory_ro() can fail, leaving memory unprotected.

Check its return and take it into account as an error.

Link: https://github.com/KSPP/linux/issues/7
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: linux-hardening@vger.kernel.org <linux-hardening@vger.kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Message-ID: <286def78955e04382b227cb3e4b6ba272a7442e3.1709850515.git.christophe.leroy@csgroup.eu>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-05 09:33:49 +02:00
Daniel Borkmann 511804ab70 bpf: Fix overrunning reservations in ringbuf
[ Upstream commit cfa1a2329a691ffd991fcf7248a57d752e712881 ]

The BPF ring buffer internally is implemented as a power-of-2 sized circular
buffer, with two logical and ever-increasing counters: consumer_pos is the
consumer counter to show which logical position the consumer consumed the
data, and producer_pos which is the producer counter denoting the amount of
data reserved by all producers.

Each time a record is reserved, the producer that "owns" the record will
successfully advance producer counter. In user space each time a record is
read, the consumer of the data advanced the consumer counter once it finished
processing. Both counters are stored in separate pages so that from user
space, the producer counter is read-only and the consumer counter is read-write.

One aspect that simplifies and thus speeds up the implementation of both
producers and consumers is how the data area is mapped twice contiguously
back-to-back in the virtual memory, allowing to not take any special measures
for samples that have to wrap around at the end of the circular buffer data
area, because the next page after the last data page would be first data page
again, and thus the sample will still appear completely contiguous in virtual
memory.

Each record has a struct bpf_ringbuf_hdr { u32 len; u32 pg_off; } header for
book-keeping the length and offset, and is inaccessible to the BPF program.
Helpers like bpf_ringbuf_reserve() return `(void *)hdr + BPF_RINGBUF_HDR_SZ`
for the BPF program to use. Bing-Jhong and Muhammad reported that it is however
possible to make a second allocated memory chunk overlapping with the first
chunk and as a result, the BPF program is now able to edit first chunk's
header.

For example, consider the creation of a BPF_MAP_TYPE_RINGBUF map with size
of 0x4000. Next, the consumer_pos is modified to 0x3000 /before/ a call to
bpf_ringbuf_reserve() is made. This will allocate a chunk A, which is in
[0x0,0x3008], and the BPF program is able to edit [0x8,0x3008]. Now, lets
allocate a chunk B with size 0x3000. This will succeed because consumer_pos
was edited ahead of time to pass the `new_prod_pos - cons_pos > rb->mask`
check. Chunk B will be in range [0x3008,0x6010], and the BPF program is able
to edit [0x3010,0x6010]. Due to the ring buffer memory layout mentioned
earlier, the ranges [0x0,0x4000] and [0x4000,0x8000] point to the same data
pages. This means that chunk B at [0x4000,0x4008] is chunk A's header.
bpf_ringbuf_submit() / bpf_ringbuf_discard() use the header's pg_off to then
locate the bpf_ringbuf itself via bpf_ringbuf_restore_from_rec(). Once chunk
B modified chunk A's header, then bpf_ringbuf_commit() refers to the wrong
page and could cause a crash.

Fix it by calculating the oldest pending_pos and check whether the range
from the oldest outstanding record to the newest would span beyond the ring
buffer size. If that is the case, then reject the request. We've tested with
the ring buffer benchmark in BPF selftests (./benchs/run_bench_ringbufs.sh)
before/after the fix and while it seems a bit slower on some benchmarks, it
is still not significantly enough to matter.

Fixes: 457f44363a ("bpf: Implement BPF ring buffer and verifier support for it")
Reported-by: Bing-Jhong Billy Jheng <billy@starlabs.sg>
Reported-by: Muhammad Ramdhan <ramdhan@starlabs.sg>
Co-developed-by: Bing-Jhong Billy Jheng <billy@starlabs.sg>
Co-developed-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Bing-Jhong Billy Jheng <billy@starlabs.sg>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240621140828.18238-1-daniel@iogearbox.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-05 09:33:47 +02:00
Yonghong Song 8d02ead6d0 bpf: Add missed var_off setting in coerce_subreg_to_size_sx()
[ Upstream commit 44b7f7151dfc2e0947f39ed4b9bc4b0c2ccd46fc ]

In coerce_subreg_to_size_sx(), for the case where upper
sign extension bits are the same for smax32 and smin32
values, we missed to setup properly. This is especially
problematic if both smax32 and smin32's sign extension
bits are 1.

The following is a simple example illustrating the inconsistent
verifier states due to missed var_off:

  0: (85) call bpf_get_prandom_u32#7    ; R0_w=scalar()
  1: (bf) r3 = r0                       ; R0_w=scalar(id=1) R3_w=scalar(id=1)
  2: (57) r3 &= 15                      ; R3_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=15,var_off=(0x0; 0xf))
  3: (47) r3 |= 128                     ; R3_w=scalar(smin=umin=smin32=umin32=128,smax=umax=smax32=umax32=143,var_off=(0x80; 0xf))
  4: (bc) w7 = (s8)w3
  REG INVARIANTS VIOLATION (alu): range bounds violation u64=[0xffffff80, 0x8f] s64=[0xffffff80, 0x8f]
    u32=[0xffffff80, 0x8f] s32=[0x80, 0xffffff8f] var_off=(0x80, 0xf)

The var_off=(0x80, 0xf) is not correct, and the correct one should
be var_off=(0xffffff80; 0xf) since from insn 3, we know that at
insn 4, the sign extension bits will be 1. This patch fixed this
issue by setting var_off properly.

Fixes: 8100928c88 ("bpf: Support new sign-extension mov insns")
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240615174632.3995278-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-05 09:33:45 +02:00
Yonghong Song 185dca8755 bpf: Add missed var_off setting in set_sext32_default_val()
[ Upstream commit 380d5f89a4815ff88461a45de2fb6f28533df708 ]

Zac reported a verification failure and Alexei reproduced the issue
with a simple reproducer ([1]). The verification failure is due to missed
setting for var_off.

The following is the reproducer in [1]:
  0: R1=ctx() R10=fp0
  0: (71) r3 = *(u8 *)(r10 -387)        ;
     R3_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff)) R10=fp0
  1: (bc) w7 = (s8)w3                   ;
     R3_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff))
     R7_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=127,var_off=(0x0; 0x7f))
  2: (36) if w7 >= 0x2533823b goto pc-3
     mark_precise: frame0: last_idx 2 first_idx 0 subseq_idx -1
     mark_precise: frame0: regs=r7 stack= before 1: (bc) w7 = (s8)w3
     mark_precise: frame0: regs=r3 stack= before 0: (71) r3 = *(u8 *)(r10 -387)
  2: R7_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=127,var_off=(0x0; 0x7f))
  3: (b4) w0 = 0                        ; R0_w=0
  4: (95) exit

Note that after insn 1, the var_off for R7 is (0x0; 0x7f). This is not correct
since upper 24 bits of w7 could be 0 or 1. So correct var_off should be
(0x0; 0xffffffff). Missing var_off setting in set_sext32_default_val() caused later
incorrect analysis in zext_32_to_64(dst_reg) and reg_bounds_sync(dst_reg).

To fix the issue, set var_off correctly in set_sext32_default_val(). The correct
reg state after insn 1 becomes:
  1: (bc) w7 = (s8)w3                   ;
     R3_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff))
     R7_w=scalar(smin=0,smax=umax=0xffffffff,smin32=-128,smax32=127,var_off=(0x0; 0xffffffff))
and at insn 2, the verifier correctly determines either branch is possible.

  [1] https://lore.kernel.org/bpf/CAADnVQLPU0Shz7dWV4bn2BgtGdxN3uFHPeobGBA72tpg5Xoykw@mail.gmail.com/

Fixes: 8100928c88 ("bpf: Support new sign-extension mov insns")
Reported-by: Zac Ecob <zacecob@protonmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240615174626.3994813-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-05 09:33:45 +02:00
Linus Torvalds 25f8b9a781 kprobe/ftrace: fix build error due to bad function definition
commit 4b377b4868ef17b040065bd468668c707d2477a5 upstream.

Commit 1a7d0890dd4a ("kprobe/ftrace: bail out if ftrace was killed")
introduced a bad K&R function definition, which we haven't accepted in a
long long time.

Gcc seems to let it slide, but clang notices with the appropriate error:

  kernel/kprobes.c:1140:24: error: a function declaration without a prototype is deprecated in all >
   1140 | void kprobe_ftrace_kill()
        |                        ^
        |                         void

but this commit was apparently never in linux-next before it was sent
upstream, so it didn't get the appropriate build test coverage.

Fixes: 1a7d0890dd4a kprobe/ftrace: bail out if ftrace was killed
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-27 13:49:15 +02:00
Jeff Johnson 6408fcfea4 tracing: Add MODULE_DESCRIPTION() to preemptirq_delay_test
[ Upstream commit 23748e3e0fbfe471eff5ce439921629f6a427828 ]

Fix the 'make W=1' warning:

WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/trace/preemptirq_delay_test.o

Link: https://lore.kernel.org/linux-trace-kernel/20240518-md-preemptirq_delay_test-v1-1-387d11b30d85@quicinc.com

Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: f96e8577da ("lib: Add module for testing preemptoff/irqsoff latency tracers")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-27 13:49:14 +02:00
Aleksandr Nogikh 637619b02c kcov: don't lose track of remote references during softirqs
commit 01c8f9806bde438ca1c8cbbc439f0a14a6694f6c upstream.

In kcov_remote_start()/kcov_remote_stop(), we swap the previous KCOV
metadata of the current task into a per-CPU variable.  However, the
kcov_mode_enabled(mode) check is not sufficient in the case of remote KCOV
coverage: current->kcov_mode always remains KCOV_MODE_DISABLED for remote
KCOV objects.

If the original task that has invoked the KCOV_REMOTE_ENABLE ioctl happens
to get interrupted and kcov_remote_start() is called, it ultimately leads
to kcov_remote_stop() NOT restoring the original KCOV reference.  So when
the task exits, all registered remote KCOV handles remain active forever.

The most uncomfortable effect (at least for syzkaller) is that the bug
prevents the reuse of the same /sys/kernel/debug/kcov descriptor.  If
we obtain it in the parent process and then e.g.  drop some
capabilities and continuously fork to execute individual programs, at
some point current->kcov of the forked process is lost,
kcov_task_exit() takes no action, and all KCOV_REMOTE_ENABLE ioctls
calls from subsequent forks fail.

And, yes, the efficiency is also affected if we keep on losing remote
kcov objects.
a) kcov_remote_map keeps on growing forever.
b) (If I'm not mistaken), we're also not freeing the memory referenced
by kcov->area.

Fix it by introducing a special kcov_mode that is assigned to the task
that owns a KCOV remote object.  It makes kcov_mode_enabled() return true
and yet does not trigger coverage collection in __sanitizer_cov_trace_pc()
and write_comp_data().

[nogikh@google.com: replace WRITE_ONCE() with an ordinary assignment]
  Link: https://lkml.kernel.org/r/20240614171221.2837584-1-nogikh@google.com
Link: https://lkml.kernel.org/r/20240611133229.527822-1-nogikh@google.com
Fixes: 5ff3b30ab5 ("kcov: collect coverage from interrupts")
Signed-off-by: Aleksandr Nogikh <nogikh@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Tested-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Marco Elver <elver@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-27 13:49:13 +02:00
Peter Oberparleiter ae30200ecc gcov: add support for GCC 14
commit c1558bc57b8e5b4da5d821537cd30e2e660861d8 upstream.

Using gcov on kernels compiled with GCC 14 results in truncated 16-byte
long .gcda files with no usable data.  To fix this, update GCOV_COUNTERS
to match the value defined by GCC 14.

Tested with GCC versions 14.1.0 and 13.2.0.

Link: https://lkml.kernel.org/r/20240610092743.1609845-1-oberpar@linux.ibm.com
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reported-by: Allison Henderson <allison.henderson@oracle.com>
Reported-by: Chuck Lever III <chuck.lever@oracle.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-27 13:49:13 +02:00
Masami Hiramatsu (Google) 55d5d08174 tracing: Build event generation tests only as modules
[ Upstream commit 3572bd5689b0812b161b40279e39ca5b66d73e88 ]

The kprobes and synth event generation test modules add events and lock
(get a reference) those event file reference in module init function,
and unlock and delete it in module exit function. This is because those
are designed for playing as modules.

If we make those modules as built-in, those events are left locked in the
kernel, and never be removed. This causes kprobe event self-test failure
as below.

[   97.349708] ------------[ cut here ]------------
[   97.353453] WARNING: CPU: 3 PID: 1 at kernel/trace/trace_kprobe.c:2133 kprobe_trace_self_tests_init+0x3f1/0x480
[   97.357106] Modules linked in:
[   97.358488] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 6.9.0-g699646734ab5-dirty #14
[   97.361556] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
[   97.363880] RIP: 0010:kprobe_trace_self_tests_init+0x3f1/0x480
[   97.365538] Code: a8 24 08 82 e9 ae fd ff ff 90 0f 0b 90 48 c7 c7 e5 aa 0b 82 e9 ee fc ff ff 90 0f 0b 90 48 c7 c7 2d 61 06 82 e9 8e fd ff ff 90 <0f> 0b 90 48 c7 c7 33 0b 0c 82 89 c6 e8 6e 03 1f ff 41 ff c7 e9 90
[   97.370429] RSP: 0000:ffffc90000013b50 EFLAGS: 00010286
[   97.371852] RAX: 00000000fffffff0 RBX: ffff888005919c00 RCX: 0000000000000000
[   97.373829] RDX: ffff888003f40000 RSI: ffffffff8236a598 RDI: ffff888003f40a68
[   97.375715] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
[   97.377675] R10: ffffffff811c9ae5 R11: ffffffff8120c4e0 R12: 0000000000000000
[   97.379591] R13: 0000000000000001 R14: 0000000000000015 R15: 0000000000000000
[   97.381536] FS:  0000000000000000(0000) GS:ffff88807dcc0000(0000) knlGS:0000000000000000
[   97.383813] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   97.385449] CR2: 0000000000000000 CR3: 0000000002244000 CR4: 00000000000006b0
[   97.387347] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   97.389277] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   97.391196] Call Trace:
[   97.391967]  <TASK>
[   97.392647]  ? __warn+0xcc/0x180
[   97.393640]  ? kprobe_trace_self_tests_init+0x3f1/0x480
[   97.395181]  ? report_bug+0xbd/0x150
[   97.396234]  ? handle_bug+0x3e/0x60
[   97.397311]  ? exc_invalid_op+0x1a/0x50
[   97.398434]  ? asm_exc_invalid_op+0x1a/0x20
[   97.399652]  ? trace_kprobe_is_busy+0x20/0x20
[   97.400904]  ? tracing_reset_all_online_cpus+0x15/0x90
[   97.402304]  ? kprobe_trace_self_tests_init+0x3f1/0x480
[   97.403773]  ? init_kprobe_trace+0x50/0x50
[   97.404972]  do_one_initcall+0x112/0x240
[   97.406113]  do_initcall_level+0x95/0xb0
[   97.407286]  ? kernel_init+0x1a/0x1a0
[   97.408401]  do_initcalls+0x3f/0x70
[   97.409452]  kernel_init_freeable+0x16f/0x1e0
[   97.410662]  ? rest_init+0x1f0/0x1f0
[   97.411738]  kernel_init+0x1a/0x1a0
[   97.412788]  ret_from_fork+0x39/0x50
[   97.413817]  ? rest_init+0x1f0/0x1f0
[   97.414844]  ret_from_fork_asm+0x11/0x20
[   97.416285]  </TASK>
[   97.417134] irq event stamp: 13437323
[   97.418376] hardirqs last  enabled at (13437337): [<ffffffff8110bc0c>] console_unlock+0x11c/0x150
[   97.421285] hardirqs last disabled at (13437370): [<ffffffff8110bbf1>] console_unlock+0x101/0x150
[   97.423838] softirqs last  enabled at (13437366): [<ffffffff8108e17f>] handle_softirqs+0x23f/0x2a0
[   97.426450] softirqs last disabled at (13437393): [<ffffffff8108e346>] __irq_exit_rcu+0x66/0xd0
[   97.428850] ---[ end trace 0000000000000000 ]---

And also, since we can not cleanup dynamic_event file, ftracetest are
failed too.

To avoid these issues, build these tests only as modules.

Link: https://lore.kernel.org/all/171811263754.85078.5877446624311852525.stgit@devnote2/

Fixes: 9fe41efaca ("tracing: Add synth event generation test module")
Fixes: 64836248dd ("tracing: Add kprobe event command generation test module")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-27 13:49:05 +02:00
Stephen Brennan ae0d1ea3e8 kprobe/ftrace: bail out if ftrace was killed
[ Upstream commit 1a7d0890dd4a502a202aaec792a6c04e6e049547 ]

If an error happens in ftrace, ftrace_kill() will prevent disarming
kprobes. Eventually, the ftrace_ops associated with the kprobes will be
freed, yet the kprobes will still be active, and when triggered, they
will use the freed memory, likely resulting in a page fault and panic.

This behavior can be reproduced quite easily, by creating a kprobe and
then triggering a ftrace_kill(). For simplicity, we can simulate an
ftrace error with a kernel module like [1]:

[1]: https://github.com/brenns10/kernel_stuff/tree/master/ftrace_killer

  sudo perf probe --add commit_creds
  sudo perf trace -e probe:commit_creds
  # In another terminal
  make
  sudo insmod ftrace_killer.ko  # calls ftrace_kill(), simulating bug
  # Back to perf terminal
  # ctrl-c
  sudo perf probe --del commit_creds

After a short period, a page fault and panic would occur as the kprobe
continues to execute and uses the freed ftrace_ops. While ftrace_kill()
is supposed to be used only in extreme circumstances, it is invoked in
FTRACE_WARN_ON() and so there are many places where an unexpected bug
could be triggered, yet the system may continue operating, possibly
without the administrator noticing. If ftrace_kill() does not panic the
system, then we should do everything we can to continue operating,
rather than leave a ticking time bomb.

Link: https://lore.kernel.org/all/20240501162956.229427-1-stephen.s.brennan@oracle.com/

Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-27 13:49:03 +02:00
Zqiang 3afcca7bcc rcutorture: Fix invalid context warning when enable srcu barrier testing
[ Upstream commit 668c0406d887467d53f8fe79261dda1d22d5b671 ]

When the torture_type is set srcu or srcud and cb_barrier is
non-zero, running the rcutorture test will trigger the
following warning:

[  163.910989][    C1] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
[  163.910994][    C1] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 0, name: swapper/1
[  163.910999][    C1] preempt_count: 10001, expected: 0
[  163.911002][    C1] RCU nest depth: 0, expected: 0
[  163.911005][    C1] INFO: lockdep is turned off.
[  163.911007][    C1] irq event stamp: 30964
[  163.911010][    C1] hardirqs last  enabled at (30963): [<ffffffffabc7df52>] do_idle+0x362/0x500
[  163.911018][    C1] hardirqs last disabled at (30964): [<ffffffffae616eff>] sysvec_call_function_single+0xf/0xd0
[  163.911025][    C1] softirqs last  enabled at (0): [<ffffffffabb6475f>] copy_process+0x16ff/0x6580
[  163.911033][    C1] softirqs last disabled at (0): [<0000000000000000>] 0x0
[  163.911038][    C1] Preemption disabled at:
[  163.911039][    C1] [<ffffffffacf1964b>] stack_depot_save_flags+0x24b/0x6c0
[  163.911063][    C1] CPU: 1 PID: 0 Comm: swapper/1 Tainted: G        W          6.8.0-rc4-rt4-yocto-preempt-rt+ #3 1e39aa9a737dd024a3275c4f835a872f673a7d3a
[  163.911071][    C1] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
[  163.911075][    C1] Call Trace:
[  163.911078][    C1]  <IRQ>
[  163.911080][    C1]  dump_stack_lvl+0x88/0xd0
[  163.911089][    C1]  dump_stack+0x10/0x20
[  163.911095][    C1]  __might_resched+0x36f/0x530
[  163.911105][    C1]  rt_spin_lock+0x82/0x1c0
[  163.911112][    C1]  spin_lock_irqsave_ssp_contention+0xb8/0x100
[  163.911121][    C1]  srcu_gp_start_if_needed+0x782/0xf00
[  163.911128][    C1]  ? _raw_spin_unlock_irqrestore+0x46/0x70
[  163.911136][    C1]  ? debug_object_active_state+0x336/0x470
[  163.911148][    C1]  ? __pfx_srcu_gp_start_if_needed+0x10/0x10
[  163.911156][    C1]  ? __pfx_lock_release+0x10/0x10
[  163.911165][    C1]  ? __pfx_rcu_torture_barrier_cbf+0x10/0x10
[  163.911188][    C1]  __call_srcu+0x9f/0xe0
[  163.911196][    C1]  call_srcu+0x13/0x20
[  163.911201][    C1]  srcu_torture_call+0x1b/0x30
[  163.911224][    C1]  rcu_torture_barrier1cb+0x4a/0x60
[  163.911247][    C1]  __flush_smp_call_function_queue+0x267/0xca0
[  163.911256][    C1]  ? __pfx_rcu_torture_barrier1cb+0x10/0x10
[  163.911281][    C1]  generic_smp_call_function_single_interrupt+0x13/0x20
[  163.911288][    C1]  __sysvec_call_function_single+0x7d/0x280
[  163.911295][    C1]  sysvec_call_function_single+0x93/0xd0
[  163.911302][    C1]  </IRQ>
[  163.911304][    C1]  <TASK>
[  163.911308][    C1]  asm_sysvec_call_function_single+0x1b/0x20
[  163.911313][    C1] RIP: 0010:default_idle+0x17/0x20
[  163.911326][    C1] RSP: 0018:ffff888001997dc8 EFLAGS: 00000246
[  163.911333][    C1] RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffffffffae618b51
[  163.911337][    C1] RDX: 0000000000000000 RSI: ffffffffaea80920 RDI: ffffffffaec2de80
[  163.911342][    C1] RBP: ffff888001997dc8 R08: 0000000000000001 R09: ffffed100d740cad
[  163.911346][    C1] R10: ffffed100d740cac R11: ffff88806ba06563 R12: 0000000000000001
[  163.911350][    C1] R13: ffffffffafe460c0 R14: ffffffffafe460c0 R15: 0000000000000000
[  163.911358][    C1]  ? ct_kernel_exit.constprop.3+0x121/0x160
[  163.911369][    C1]  ? lockdep_hardirqs_on+0xc4/0x150
[  163.911376][    C1]  arch_cpu_idle+0x9/0x10
[  163.911383][    C1]  default_idle_call+0x7a/0xb0
[  163.911390][    C1]  do_idle+0x362/0x500
[  163.911398][    C1]  ? __pfx_do_idle+0x10/0x10
[  163.911404][    C1]  ? complete_with_flags+0x8b/0xb0
[  163.911416][    C1]  cpu_startup_entry+0x58/0x70
[  163.911423][    C1]  start_secondary+0x221/0x280
[  163.911430][    C1]  ? __pfx_start_secondary+0x10/0x10
[  163.911440][    C1]  secondary_startup_64_no_verify+0x17f/0x18b
[  163.911455][    C1]  </TASK>

This commit therefore use smp_call_on_cpu() instead of
smp_call_function_single(), make rcu_torture_barrier1cb() invoked
happens on task-context.

Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-27 13:49:01 +02:00
Zqiang 93b7d58202 rcutorture: Make stall-tasks directly exit when rcutorture tests end
[ Upstream commit 431315a563015f259b28e34c5842f6166439e969 ]

When the rcutorture tests start to exit, the rcu_torture_cleanup() is
invoked to stop kthreads and release resources, if the stall-task
kthreads exist, cpu-stall has started and the rcutorture.stall_cpu
is set to a larger value, the rcu_torture_cleanup() will be blocked
for a long time and the hung-task may occur, this commit therefore
add kthread_should_stop() to the loop of cpu-stall operation, when
rcutorture tests ends, no need to wait for cpu-stall to end, exit
directly.

Use the following command to test:

insmod rcutorture.ko torture_type=srcu fwd_progress=0 stat_interval=4
stall_cpu_block=1 stall_cpu=200 stall_cpu_holdoff=10 read_exit_burst=0
object_debug=1
rmmod rcutorture

[15361.918610] INFO: task rmmod:878 blocked for more than 122 seconds.
[15361.918613]       Tainted: G        W
6.8.0-rc2-yoctodev-standard+ #25
[15361.918615] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
disables this message.
[15361.918616] task:rmmod           state:D stack:0     pid:878
tgid:878   ppid:773    flags:0x00004002
[15361.918621] Call Trace:
[15361.918623]  <TASK>
[15361.918626]  __schedule+0xc0d/0x28f0
[15361.918631]  ? __pfx___schedule+0x10/0x10
[15361.918635]  ? rcu_is_watching+0x19/0xb0
[15361.918638]  ? schedule+0x1f6/0x290
[15361.918642]  ? __pfx_lock_release+0x10/0x10
[15361.918645]  ? schedule+0xc9/0x290
[15361.918648]  ? schedule+0xc9/0x290
[15361.918653]  ? trace_preempt_off+0x54/0x100
[15361.918657]  ? schedule+0xc9/0x290
[15361.918661]  schedule+0xd0/0x290
[15361.918665]  schedule_timeout+0x56d/0x7d0
[15361.918669]  ? debug_smp_processor_id+0x1b/0x30
[15361.918672]  ? rcu_is_watching+0x19/0xb0
[15361.918676]  ? __pfx_schedule_timeout+0x10/0x10
[15361.918679]  ? debug_smp_processor_id+0x1b/0x30
[15361.918683]  ? rcu_is_watching+0x19/0xb0
[15361.918686]  ? wait_for_completion+0x179/0x4c0
[15361.918690]  ? __pfx_lock_release+0x10/0x10
[15361.918693]  ? __kasan_check_write+0x18/0x20
[15361.918696]  ? wait_for_completion+0x9d/0x4c0
[15361.918700]  ? _raw_spin_unlock_irq+0x36/0x50
[15361.918703]  ? wait_for_completion+0x179/0x4c0
[15361.918707]  ? _raw_spin_unlock_irq+0x36/0x50
[15361.918710]  ? wait_for_completion+0x179/0x4c0
[15361.918714]  ? trace_preempt_on+0x54/0x100
[15361.918718]  ? wait_for_completion+0x179/0x4c0
[15361.918723]  wait_for_completion+0x181/0x4c0
[15361.918728]  ? __pfx_wait_for_completion+0x10/0x10
[15361.918738]  kthread_stop+0x152/0x470
[15361.918742]  _torture_stop_kthread+0x44/0xc0 [torture
7af7f9cbba28271a10503b653f9e05d518fbc8c3]
[15361.918752]  rcu_torture_cleanup+0x2ac/0xe90 [rcutorture
f2cb1f556ee7956270927183c4c2c7749a336529]
[15361.918766]  ? __pfx_rcu_torture_cleanup+0x10/0x10 [rcutorture
f2cb1f556ee7956270927183c4c2c7749a336529]
[15361.918777]  ? __kasan_check_write+0x18/0x20
[15361.918781]  ? __mutex_unlock_slowpath+0x17c/0x670
[15361.918789]  ? __might_fault+0xcd/0x180
[15361.918793]  ? find_module_all+0x104/0x1d0
[15361.918799]  __x64_sys_delete_module+0x2a4/0x3f0
[15361.918803]  ? __pfx___x64_sys_delete_module+0x10/0x10
[15361.918807]  ? syscall_exit_to_user_mode+0x149/0x280

Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-27 13:49:01 +02:00
Paul E. McKenney 2e5ed1130e rcutorture: Fix rcu_torture_one_read() pipe_count overflow comment
[ Upstream commit 8b9b443fa860276822b25057cb3ff3b28734dec0 ]

The "pipe_count > RCU_TORTURE_PIPE_LEN" check has a comment saying "Should
not happen, but...".  This is only true when testing an RCU whose grace
periods are always long enough.  This commit therefore fixes this comment.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Closes: https://lore.kernel.org/lkml/CAHk-=wi7rJ-eGq+xaxVfzFEgbL9tdf6Kc8Z89rCpfcQOKm74Tw@mail.gmail.com/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-27 13:49:01 +02:00
Herbert Xu 7220b9795d padata: Disable BH when taking works lock on MT path
[ Upstream commit 58329c4312031603bb1786b44265c26d5065fe72 ]

As the old padata code can execute in softirq context, disable
softirqs for the new padata_do_mutithreaded code too as otherwise
lockdep will get antsy.

Reported-by: syzbot+0cb5bb0f4bf9e79db3b3@syzkaller.appspotmail.com
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-27 13:49:00 +02:00
Oleg Nesterov 3466abafa9 zap_pid_ns_processes: clear TIF_NOTIFY_SIGNAL along with TIF_SIGPENDING
[ Upstream commit 7fea700e04bd3f424c2d836e98425782f97b494e ]

kernel_wait4() doesn't sleep and returns -EINTR if there is no
eligible child and signal_pending() is true.

That is why zap_pid_ns_processes() clears TIF_SIGPENDING but this is not
enough, it should also clear TIF_NOTIFY_SIGNAL to make signal_pending()
return false and avoid a busy-wait loop.

Link: https://lkml.kernel.org/r/20240608120616.GB7947@redhat.com
Fixes: 12db8b6900 ("entry: Add support for TIF_NOTIFY_SIGNAL")
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Rachel Menge <rachelmenge@linux.microsoft.com>
Closes: https://lore.kernel.org/all/1386cd49-36d0-4a5c-85e9-bc42056a5a38@linux.microsoft.com/
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Tested-by: Wei Fu <fuweid89@gmail.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Cc: Allen Pais <apais@linux.microsoft.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joel Granados <j.granados@samsung.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Zqiang <qiang.zhang1211@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-21 14:38:50 +02:00
Sam James dd782da470 Revert "fork: defer linking file vma until vma is fully initialized"
This reverts commit cec11fa2eb which is commit
35e351780fa9d8240dd6f7e4f245f9ea37e96c19 upstream.

The backport is incomplete and causes xfstests failures. The consequences
of the incomplete backport seem worse than the original issue, so pick
the lesser evil and revert until a full backport is ready.

Link: https://lore.kernel.org/stable/20240604004751.3883227-1-leah.rumancik@gmail.com/
Reported-by: Leah Rumancik <leah.rumancik@gmail.com>
Signed-off-by: Sam James <sam@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-21 14:38:47 +02:00
Oleg Nesterov 93d61e1bac tick/nohz_full: Don't abuse smp_call_function_single() in tick_setup_device()
commit 07c54cc5988f19c9642fd463c2dbdac7fc52f777 upstream.

After the recent commit 5097cbcb38e6 ("sched/isolation: Prevent boot crash
when the boot CPU is nohz_full") the kernel no longer crashes, but there is
another problem.

In this case tick_setup_device() calls tick_take_do_timer_from_boot() to
update tick_do_timer_cpu and this triggers the WARN_ON_ONCE(irqs_disabled)
in smp_call_function_single().

Kill tick_take_do_timer_from_boot() and just use WRITE_ONCE(), the new
comment explains why this is safe (thanks Thomas!).

Fixes: 08ae95f4fd ("nohz_full: Allow the boot CPU to be nohz_full")
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240528122019.GA28794@redhat.com
Link: https://lore.kernel.org/all/20240522151742.GA10400@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-21 14:38:46 +02:00
Petr Tesarik f8474caf39 swiotlb: extend buffer pre-padding to alloc_align_mask if necessary
commit af133562d5aff41fcdbe51f1a504ae04788b5fc0 upstream.

Allow a buffer pre-padding of up to alloc_align_mask, even if it requires
allocating additional IO TLB slots.

If the allocation alignment is bigger than IO_TLB_SIZE and min_align_mask
covers any non-zero bits in the original address between IO_TLB_SIZE and
alloc_align_mask, these bits are not preserved in the swiotlb buffer
address.

To fix this case, increase the allocation size and use a larger offset
within the allocated buffer. As a result, extra padding slots may be
allocated before the mapping start address.

Leave orig_addr in these padding slots initialized to INVALID_PHYS_ADDR.
These slots do not correspond to any CPU buffer, so attempts to sync the
data should be ignored.

The padding slots should be automatically released when the buffer is
unmapped. However, swiotlb_tbl_unmap_single() takes only the address of the
DMA buffer slot, not the first padding slot. Save the number of padding
slots in struct io_tlb_slot and use it to adjust the slot index in
swiotlb_release_slots(), so all allocated slots are properly freed.

Cc: stable@vger.kernel.org # v6.6+
Fixes: 2fd4fa5d3fb5 ("swiotlb: Fix alignment checks when both allocation and DMA masks are present")
Link: https://lore.kernel.org/linux-iommu/20240311210507.217daf8b@meshulam.tesarici.cz/
Signed-off-by: Petr Tesarik <petr.tesarik1@huawei-partners.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-21 14:38:46 +02:00
Will Deacon 6c385c1fa0 swiotlb: Reinstate page-alignment for mappings >= PAGE_SIZE
commit 14cebf689a78e8a1c041138af221ef6eac6bc7da upstream.

For swiotlb allocations >= PAGE_SIZE, the slab search historically
adjusted the stride to avoid checking unaligned slots. This had the
side-effect of aligning large mapping requests to PAGE_SIZE, but that
was broken by 0eee5ae102 ("swiotlb: fix slot alignment checks").

Since this alignment could be relied upon drivers, reinstate PAGE_SIZE
alignment for swiotlb mappings >= PAGE_SIZE.

Cc: stable@vger.kernel.org # v6.6+
Reported-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Petr Tesarik <petr.tesarik1@huawei-partners.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-21 14:38:46 +02:00
Will Deacon 6033fc9522 swiotlb: Enforce page alignment in swiotlb_alloc()
commit 823353b7cf0ea9dfb09f5181d5fb2825d727200b upstream.

When allocating pages from a restricted DMA pool in swiotlb_alloc(),
the buffer address is blindly converted to a 'struct page *' that is
returned to the caller. In the unlikely event of an allocation bug,
page-unaligned addresses are not detected and slots can silently be
double-allocated.

Add a simple check of the buffer alignment in swiotlb_alloc() to make
debugging a little easier if something has gone wonky.

Cc: stable@vger.kernel.org # v6.6+
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Petr Tesarik <petr.tesarik1@huawei-partners.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-21 14:38:46 +02:00
Matthias Maennich 5fc6b708ef kheaders: explicitly define file modes for archived headers
commit 3bd27a847a3a4827a948387cc8f0dbc9fa5931d5 upstream.

Build environments might be running with different umask settings
resulting in indeterministic file modes for the files contained in
kheaders.tar.xz. The file itself is served with 444, i.e. world
readable. Archive the files explicitly with 744,a+X to improve
reproducibility across build environments.

--mode=0444 is not suitable as directories need to be executable. Also,
444 makes it hard to delete all the readonly files after extraction.

Cc: stable@vger.kernel.org
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-21 14:38:40 +02:00
Haifeng Xu 809a2ed171 perf/core: Fix missing wakeup when waiting for context reference
commit 74751ef5c1912ebd3e65c3b65f45587e05ce5d36 upstream.

In our production environment, we found many hung tasks which are
blocked for more than 18 hours. Their call traces are like this:

[346278.191038] __schedule+0x2d8/0x890
[346278.191046] schedule+0x4e/0xb0
[346278.191049] perf_event_free_task+0x220/0x270
[346278.191056] ? init_wait_var_entry+0x50/0x50
[346278.191060] copy_process+0x663/0x18d0
[346278.191068] kernel_clone+0x9d/0x3d0
[346278.191072] __do_sys_clone+0x5d/0x80
[346278.191076] __x64_sys_clone+0x25/0x30
[346278.191079] do_syscall_64+0x5c/0xc0
[346278.191083] ? syscall_exit_to_user_mode+0x27/0x50
[346278.191086] ? do_syscall_64+0x69/0xc0
[346278.191088] ? irqentry_exit_to_user_mode+0x9/0x20
[346278.191092] ? irqentry_exit+0x19/0x30
[346278.191095] ? exc_page_fault+0x89/0x160
[346278.191097] ? asm_exc_page_fault+0x8/0x30
[346278.191102] entry_SYSCALL_64_after_hwframe+0x44/0xae

The task was waiting for the refcount become to 1, but from the vmcore,
we found the refcount has already been 1. It seems that the task didn't
get woken up by perf_event_release_kernel() and got stuck forever. The
below scenario may cause the problem.

Thread A					Thread B
...						...
perf_event_free_task				perf_event_release_kernel
						   ...
						   acquire event->child_mutex
						   ...
						   get_ctx
   ...						   release event->child_mutex
   acquire ctx->mutex
   ...
   perf_free_event (acquire/release event->child_mutex)
   ...
   release ctx->mutex
   wait_var_event
						   acquire ctx->mutex
						   acquire event->child_mutex
						   # move existing events to free_list
						   release event->child_mutex
						   release ctx->mutex
						   put_ctx
...						...

In this case, all events of the ctx have been freed, so we couldn't
find the ctx in free_list and Thread A will miss the wakeup. It's thus
necessary to add a wakeup after dropping the reference.

Fixes: 1cf8dfe8a6 ("perf/core: Fix race between close() and fork()")
Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20240513103948.33570-1-haifeng.xu@shopee.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-21 14:38:39 +02:00
Andrii Nakryiko 39a143a2b0 bpf: fix multi-uprobe PID filtering logic
[ Upstream commit 46ba0e49b64232adac35a2bc892f1710c5b0fb7f ]

Current implementation of PID filtering logic for multi-uprobes in
uprobe_prog_run() is filtering down to exact *thread*, while the intent
for PID filtering it to filter by *process* instead. The check in
uprobe_prog_run() also differs from the analogous one in
uprobe_multi_link_filter() for some reason. The latter is correct,
checking task->mm, not the task itself.

Fix the check in uprobe_prog_run() to perform the same task->mm check.

While doing this, we also update get_pid_task() use to use PIDTYPE_TGID
type of lookup, given the intent is to get a representative task of an
entire process. This doesn't change behavior, but seems more logical. It
would hold task group leader task now, not any random thread task.

Last but not least, given multi-uprobe support is half-broken due to
this PID filtering logic (depending on whether PID filtering is
important or not), we need to make it easy for user space consumers
(including libbpf) to easily detect whether PID filtering logic was
already fixed.

We do it here by adding an early check on passed pid parameter. If it's
negative (and so has no chance of being a valid PID), we return -EINVAL.
Previous behavior would eventually return -ESRCH ("No process found"),
given there can't be any process with negative PID. This subtle change
won't make any practical change in behavior, but will allow applications
to detect PID filtering fixes easily. Libbpf fixes take advantage of
this in the next patch.

Cc: stable@vger.kernel.org
Acked-by: Jiri Olsa <jolsa@kernel.org>
Fixes: b733eeade4 ("bpf: Add pid filter support for uprobe_multi link")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240521163401.3005045-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-21 14:38:22 +02:00
Cong Wang 91cff53136 bpf: Fix a potential use-after-free in bpf_link_free()
[ Upstream commit 2884dc7d08d98a89d8d65121524bb7533183a63a ]

After commit 1a80dbcb2dba, bpf_link can be freed by
link->ops->dealloc_deferred, but the code still tests and uses
link->ops->dealloc afterward, which leads to a use-after-free as
reported by syzbot. Actually, one of them should be sufficient, so
just call one of them instead of both. Also add a WARN_ON() in case
of any problematic implementation.

Fixes: 1a80dbcb2dba ("bpf: support deferring bpf_link dealloc to after RCU grace period")
Reported-by: syzbot+1989ee16d94720836244@syzkaller.appspotmail.com
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20240602182703.207276-1-xiyou.wangcong@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-21 14:38:15 +02:00
Hou Tao 2ad2f2edb9 bpf: Optimize the free of inner map
[ Upstream commit af66bfd3c8538ed21cf72af18426fc4a408665cf ]

When removing the inner map from the outer map, the inner map will be
freed after one RCU grace period and one RCU tasks trace grace
period, so it is certain that the bpf program, which may access the
inner map, has exited before the inner map is freed.

However there is no need to wait for one RCU tasks trace grace period if
the outer map is only accessed by non-sleepable program. So adding
sleepable_refcnt in bpf_map and increasing sleepable_refcnt when adding
the outer map into env->used_maps for sleepable program. Although the
max number of bpf program is INT_MAX - 1, the number of bpf programs
which are being loaded may be greater than INT_MAX, so using atomic64_t
instead of atomic_t for sleepable_refcnt. When removing the inner map
from the outer map, using sleepable_refcnt to decide whether or not a
RCU tasks trace grace period is needed before freeing the inner map.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20231204140425.1480317-6-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: 2884dc7d08d9 ("bpf: Fix a potential use-after-free in bpf_link_free()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-21 14:38:15 +02:00
Jiri Olsa 5aa03dd388 bpf: Store ref_ctr_offsets values in bpf_uprobe array
[ Upstream commit 4930b7f53a298533bc31d7540b6ea8b79a000331 ]

We will need to return ref_ctr_offsets values through link_info
interface in following change, so we need to keep them around.

Storing ref_ctr_offsets values directly into bpf_uprobe array.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/bpf/20231125193130.834322-3-jolsa@kernel.org
Stable-dep-of: 2884dc7d08d9 ("bpf: Fix a potential use-after-free in bpf_link_free()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-21 14:38:14 +02:00
dicken.ding 1c7891812d genirq/irqdesc: Prevent use-after-free in irq_find_at_or_after()
commit b84a8aba806261d2f759ccedf4a2a6a80a5e55ba upstream.

irq_find_at_or_after() dereferences the interrupt descriptor which is
returned by mt_find() while neither holding sparse_irq_lock nor RCU read
lock, which means the descriptor can be freed between mt_find() and the
dereference:

    CPU0                            CPU1
    desc = mt_find()
                                    delayed_free_desc(desc)
    irq_desc_get_irq(desc)

The use-after-free is reported by KASAN:

    Call trace:
     irq_get_next_irq+0x58/0x84
     show_stat+0x638/0x824
     seq_read_iter+0x158/0x4ec
     proc_reg_read_iter+0x94/0x12c
     vfs_read+0x1e0/0x2c8

    Freed by task 4471:
     slab_free_freelist_hook+0x174/0x1e0
     __kmem_cache_free+0xa4/0x1dc
     kfree+0x64/0x128
     irq_kobj_release+0x28/0x3c
     kobject_put+0xcc/0x1e0
     delayed_free_desc+0x14/0x2c
     rcu_do_batch+0x214/0x720

Guard the access with a RCU read lock section.

Fixes: 721255b982 ("genirq: Use a maple tree for interrupt descriptor management")
Signed-off-by: dicken.ding <dicken.ding@mediatek.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240524091739.31611-1-dicken.ding@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-16 13:47:46 +02:00
Daniel Thompson ea303a7af8 kdb: Use format-specifiers rather than memset() for padding in kdb_read()
commit c9b51ddb66b1d96e4d364c088da0f1dfb004c574 upstream.

Currently when the current line should be removed from the display
kdb_read() uses memset() to fill a temporary buffer with spaces.
The problem is not that this could be trivially implemented using a
format string rather than open coding it. The real problem is that
it is possible, on systems with a long kdb_prompt_str, to write past
the end of the tmpbuffer.

Happily, as mentioned above, this can be trivially implemented using a
format string. Make it so!

Cc: stable@vger.kernel.org
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240424-kgdb_read_refactor-v3-5-f236dbe9828d@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-16 13:47:44 +02:00
Daniel Thompson e00ec562b0 kdb: Merge identical case statements in kdb_read()
commit 6244917f377bf64719551b58592a02a0336a7439 upstream.

The code that handles case 14 (down) and case 16 (up) has been copy and
pasted despite being byte-for-byte identical. Combine them.

Cc: stable@vger.kernel.org # Not a bug fix but it is needed for later bug fixes
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240424-kgdb_read_refactor-v3-4-f236dbe9828d@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-16 13:47:44 +02:00
Daniel Thompson 958ba65a35 kdb: Fix console handling when editing and tab-completing commands
commit db2f9c7dc29114f531df4a425d0867d01e1f1e28 upstream.

Currently, if the cursor position is not at the end of the command buffer
and the user uses the Tab-complete functions, then the console does not
leave the cursor in the correct position.

For example consider the following buffer with the cursor positioned
at the ^:

md kdb_pro 10
          ^

Pressing tab should result in:

md kdb_prompt_str 10
                 ^

However this does not happen. Instead the cursor is placed at the end
(after then 10) and further cursor movement redraws incorrectly. The
same problem exists when we double-Tab but in a different part of the
code.

Fix this by sending a carriage return and then redisplaying the text to
the left of the cursor.

Cc: stable@vger.kernel.org
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240424-kgdb_read_refactor-v3-3-f236dbe9828d@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-16 13:47:43 +02:00
Daniel Thompson d373d3c633 kdb: Use format-strings rather than '\0' injection in kdb_read()
commit 09b35989421dfd5573f0b4683c7700a7483c71f9 upstream.

Currently when kdb_read() needs to reposition the cursor it uses copy and
paste code that works by injecting an '\0' at the cursor position before
delivering a carriage-return and reprinting the line (which stops at the
'\0').

Tidy up the code by hoisting the copy and paste code into an appropriately
named function. Additionally let's replace the '\0' injection with a
proper field width parameter so that the string will be abridged during
formatting instead.

Cc: stable@vger.kernel.org # Not a bug fix but it is needed for later bug fixes
Tested-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20240424-kgdb_read_refactor-v3-2-f236dbe9828d@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-16 13:47:43 +02:00
Daniel Thompson 107e825cc4 kdb: Fix buffer overflow during tab-complete
commit e9730744bf3af04cda23799029342aa3cddbc454 upstream.

Currently, when the user attempts symbol completion with the Tab key, kdb
will use strncpy() to insert the completed symbol into the command buffer.
Unfortunately it passes the size of the source buffer rather than the
destination to strncpy() with predictably horrible results. Most obviously
if the command buffer is already full but cp, the cursor position, is in
the middle of the buffer, then we will write past the end of the supplied
buffer.

Fix this by replacing the dubious strncpy() calls with memmove()/memcpy()
calls plus explicit boundary checks to make sure we have enough space
before we start moving characters around.

Reported-by: Justin Stitt <justinstitt@google.com>
Closes: https://lore.kernel.org/all/CAFhGd8qESuuifuHsNjFPR-Va3P80bxrw+LqvC8deA8GziUJLpw@mail.gmail.com/
Cc: stable@vger.kernel.org
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Justin Stitt <justinstitt@google.com>
Tested-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240424-kgdb_read_refactor-v3-1-f236dbe9828d@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-16 13:47:43 +02:00
Dongli Zhang 59f86a2908 genirq/cpuhotplug, x86/vector: Prevent vector leak during CPU offline
commit a6c11c0a5235fb144a65e0cb2ffd360ddc1f6c32 upstream.

The absence of IRQD_MOVE_PCNTXT prevents immediate effectiveness of
interrupt affinity reconfiguration via procfs. Instead, the change is
deferred until the next instance of the interrupt being triggered on the
original CPU.

When the interrupt next triggers on the original CPU, the new affinity is
enforced within __irq_move_irq(). A vector is allocated from the new CPU,
but the old vector on the original CPU remains and is not immediately
reclaimed. Instead, apicd->move_in_progress is flagged, and the reclaiming
process is delayed until the next trigger of the interrupt on the new CPU.

Upon the subsequent triggering of the interrupt on the new CPU,
irq_complete_move() adds a task to the old CPU's vector_cleanup list if it
remains online. Subsequently, the timer on the old CPU iterates over its
vector_cleanup list, reclaiming old vectors.

However, a rare scenario arises if the old CPU is outgoing before the
interrupt triggers again on the new CPU.

In that case irq_force_complete_move() is not invoked on the outgoing CPU
to reclaim the old apicd->prev_vector because the interrupt isn't currently
affine to the outgoing CPU, and irq_needs_fixup() returns false. Even
though __vector_schedule_cleanup() is later called on the new CPU, it
doesn't reclaim apicd->prev_vector; instead, it simply resets both
apicd->move_in_progress and apicd->prev_vector to 0.

As a result, the vector remains unreclaimed in vector_matrix, leading to a
CPU vector leak.

To address this issue, move the invocation of irq_force_complete_move()
before the irq_needs_fixup() call to reclaim apicd->prev_vector, if the
interrupt is currently or used to be affine to the outgoing CPU.

Additionally, reclaim the vector in __vector_schedule_cleanup() as well,
following a warning message, although theoretically it should never see
apicd->move_in_progress with apicd->prev_cpu pointing to an offline CPU.

Fixes: f0383c24b4 ("genirq/cpuhotplug: Add support for cleaning up move in progress")
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240522220218.162423-1-dongli.zhang@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-12 11:13:01 +02:00
Miguel Ojeda db93128536 kheaders: use `command -v` to test for existence of `cpio`
[ Upstream commit 6e58e0173507e506a5627741358bc770f220e356 ]

Commit 13e1df0928 ("kheaders: explicitly validate existence of cpio
command") added an explicit check for `cpio` using `type`.

However, `type` in `dash` (which is used in some popular distributions
and base images as the shell script runner) prints the missing message
to standard output, and thus no error is printed:

    $ bash -c 'type missing >/dev/null'
    bash: line 1: type: missing: not found
    $ dash -c 'type missing >/dev/null'
    $

For instance, this issue may be seen by loongarch builders, given its
defconfig enables CONFIG_IKHEADERS since commit 9cc1df421f00 ("LoongArch:
Update Loongson-3 default config file").

Therefore, use `command -v` instead to have consistent behavior, and
take the chance to provide a more explicit error.

Fixes: 13e1df0928 ("kheaders: explicitly validate existence of cpio command")
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-12 11:12:58 +02:00