In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
This patch fixes the following warning:
kernel/events/core.c: In function ‘perf_event_parse_addr_filter’:
kernel/events/core.c:9154:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
kernel = 1;
~~~~~~~^~~
kernel/events/core.c:9156:3: note: here
case IF_SRC_FILEADDR:
^~~~
Warning level 3 was used: -Wimplicit-fallthrough=3
This patch is part of the ongoing efforts to enable -Wimplicit-fallthrough.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Gustavo A. R. Silva <gustavo@embeddedor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kees Kook <keescook@chromium.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190212205430.GA8446@embeddedor
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Events with attr.bpf_event set should be considered as side-band events,
as they carry information about BPF programs.
Signed-off-by: Song Liu <songliubraving@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@fb.com
Cc: netdev@vger.kernel.org
Fixes: 6ee52e2a3f ("perf, bpf: Introduce PERF_RECORD_BPF_EVENT")
Link: http://lkml.kernel.org/r/20190226002019.3748539-2-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
perf annotate:
Wei Li:
- Fix getting source line failure
perf script:
Andi Kleen:
- Handle missing fields with -F +...
perf data:
Jiri Olsa:
- Prep work to support per-cpu files in a directory.
Intel PT:
Adrian Hunter:
- Improve thread_stack__no_call_return()
- Hide x86 retpolines in thread stacks.
- exported SQL viewer refactorings, new 'top calls' report..
Alexander Shishkin:
- Copy parent's address filter offsets on clone
- Fix address filters for vmas with non-zero offset. Applies to
ARM's CoreSight as well.
python scripts:
Tony Jones:
- Python3 support for several 'perf script' python scripts.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Merge tag 'perf-core-for-mingo-5.1-20190225' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core
Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:
perf annotate:
Wei Li:
- Fix getting source line failure
perf script:
Andi Kleen:
- Handle missing fields with -F +...
perf data:
Jiri Olsa:
- Prep work to support per-cpu files in a directory.
Intel PT:
Adrian Hunter:
- Improve thread_stack__no_call_return()
- Hide x86 retpolines in thread stacks.
- exported SQL viewer refactorings, new 'top calls' report..
Alexander Shishkin:
- Copy parent's address filter offsets on clone
- Fix address filters for vmas with non-zero offset. Applies to
ARM's CoreSight as well.
python scripts:
Tony Jones:
- Python3 support for several 'perf script' python scripts.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull networking fixes from David Miller:
"Hopefully the last pull request for this release. Fingers crossed:
1) Only refcount ESP stats on full sockets, from Martin Willi.
2) Missing barriers in AF_UNIX, from Al Viro.
3) RCU protection fixes in ipv6 route code, from Paolo Abeni.
4) Avoid false positives in untrusted GSO validation, from Willem de
Bruijn.
5) Forwarded mesh packets in mac80211 need more tailroom allocated,
from Felix Fietkau.
6) Use operstate consistently for linkup in team driver, from George
Wilkie.
7) ThunderX bug fixes from Vadim Lomovtsev. Mostly races between VF
and PF code paths.
8) Purge ipv6 exceptions during netdevice removal, from Paolo Abeni.
9) nfp eBPF code gen fixes from Jiong Wang.
10) bnxt_en firmware timeout fix from Michael Chan.
11) Use after free in udp/udpv6 error handlers, from Paolo Abeni.
12) Fix a race in x25_bind triggerable by syzbot, from Eric Dumazet"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (65 commits)
net: phy: realtek: Dummy IRQ calls for RTL8366RB
tcp: repaired skbs must init their tso_segs
net/x25: fix a race in x25_bind()
net: dsa: Remove documentation for port_fdb_prepare
Revert "bridge: do not add port to router list when receives query with source 0.0.0.0"
selftests: fib_tests: sleep after changing carrier. again.
net: set static variable an initial value in atl2_probe()
net: phy: marvell10g: Fix Multi-G advertisement to only advertise 10G
bpf, doc: add bpf list as secondary entry to maintainers file
udp: fix possible user after free in error handler
udpv6: fix possible user after free in error handler
fou6: fix proto error handler argument type
udpv6: add the required annotation to mib type
mdio_bus: Fix use-after-free on device_register fails
net: Set rtm_table to RT_TABLE_COMPAT for ipv6 for tables > 255
bnxt_en: Wait longer for the firmware message response to complete.
bnxt_en: Fix typo in firmware message timeout logic.
nfp: bpf: fix ALU32 high bits clearance bug
nfp: bpf: fix code-gen bug on BPF_ALU | BPF_XOR | BPF_K
Documentation: networking: switchdev: Update port parent ID section
...
Daniel Borkmann says:
====================
pull-request: bpf 2019-02-23
The following pull-request contains BPF updates for your *net* tree.
The main changes are:
1) Fix a bug in BPF's LPM deletion logic to match correct prefix
length, from Alban.
2) Fix AF_XDP teardown by not destroying umem prematurely as it
is still needed till all outstanding skbs are freed, from Björn.
3) Fix unkillable BPF_PROG_TEST_RUN under preempt kernel by checking
signal_pending() outside need_resched() condition which is never
triggered there, from Stanislav.
4) Fix two nfp JIT bugs, one in code emission for K-based xor, and
another one to explicitly clear upper bits in alu32, from Jiong.
5) Add bpf list address to maintainers file, from Daniel.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, the address range calculation for file-based filters works as
long as the vma that maps the matching part of the object file starts
from offset zero into the file (vm_pgoff==0). Otherwise, the resulting
filter range would be off by vm_pgoff pages. Another related problem is
that in case of a partially matching vma, that is, a vma that matches
part of a filter region, the filter range size wouldn't be adjusted.
Fix the arithmetics around address filter range calculations, taking
into account vma offset, so that the entire calculation is done before
the filter configuration is passed to the PMU drivers instead of having
those drivers do the final bit of arithmetics.
Based on the patch by Adrian Hunter <adrian.hunter.intel.com>.
Reported-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Fixes: 375637bc52 ("perf/core: Introduce address range filtering")
Link: http://lkml.kernel.org/r/20190215115655.63469-3-alexander.shishkin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When a child event is allocated in the inherit_event() path, the VMA
based filter offsets are not copied from the parent, even though the
address space mapping of the new task remains the same, which leads to
no trace for the new task until exec.
Reported-by: Mansour Alharthi <malharthi9@gatech.edu>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Fixes: 375637bc52 ("perf/core: Introduce address range filtering")
Link: http://lkml.kernel.org/r/20190215115655.63469-2-alexander.shishkin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
trie_delete_elem() was deleting an entry even though it was not matching
if the prefixlen was correct. This patch adds a check on matchlen.
Reproducer:
$ sudo bpftool map create /sys/fs/bpf/mylpm type lpm_trie key 8 value 1 entries 128 name mylpm flags 1
$ sudo bpftool map update pinned /sys/fs/bpf/mylpm key hex 10 00 00 00 aa bb cc dd value hex 01
$ sudo bpftool map dump pinned /sys/fs/bpf/mylpm
key: 10 00 00 00 aa bb cc dd value: 01
Found 1 element
$ sudo bpftool map delete pinned /sys/fs/bpf/mylpm key hex 10 00 00 00 ff ff ff ff
$ echo $?
0
$ sudo bpftool map dump pinned /sys/fs/bpf/mylpm
Found 0 elements
A similar reproducer is added in the selftests.
Without the patch:
$ sudo ./tools/testing/selftests/bpf/test_lpm_map
test_lpm_map: test_lpm_map.c:485: test_lpm_delete: Assertion `bpf_map_delete_elem(map_fd, key) == -1 && errno == ENOENT' failed.
Aborted
With the patch: test_lpm_map runs without errors.
Fixes: e454cf5958 ("bpf: Implement map_delete_elem for BPF_MAP_TYPE_LPM_TRIE")
Cc: Craig Gallek <kraig@google.com>
Signed-off-by: Alban Crequy <alban@kinvolk.io>
Acked-by: Craig Gallek <kraig@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
We've been seeing hard-to-trigger psi crashes when running inside VM
instances:
divide error: 0000 [#1] SMP PTI
Modules linked in: [...]
CPU: 0 PID: 212 Comm: kworker/0:2 Not tainted 4.16.18-119_fbk9_3817_gfe944c98d695 #119
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
Workqueue: events psi_clock
RIP: 0010:psi_update_stats+0x270/0x490
RSP: 0018:ffffc90001117e10 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff8800a35a13f8
RDX: 0000000000000000 RSI: ffff8800a35a1340 RDI: 0000000000000000
RBP: 0000000000000658 R08: ffff8800a35a1470 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00000000000f8502
FS: 0000000000000000(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbe370fa000 CR3: 00000000b1e3a000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
psi_clock+0x12/0x50
process_one_work+0x1e0/0x390
worker_thread+0x2b/0x3c0
? rescuer_thread+0x330/0x330
kthread+0x113/0x130
? kthread_create_worker_on_cpu+0x40/0x40
? SyS_exit_group+0x10/0x10
ret_from_fork+0x35/0x40
Code: 48 0f 47 c7 48 01 c2 45 85 e4 48 89 16 0f 85 e6 00 00 00 4c 8b 49 10 4c 8b 51 08 49 69 d9 f2 07 00 00 48 6b c0 64 4c 8b 29 31 d2 <48> f7 f7 49 69 d5 8d 06 00 00 48 89 c5 4c 69 f0 00 98 0b 00 48
The Code-line points to `period` being 0 inside update_stats(), and we
divide by that when calculating that period's pressure percentage.
The elapsed period should never be 0. The reason this can happen is due
to an off-by-one in the idle time / missing period calculation combined
with a coarse sched_clock() in the virtual machine.
The target time for aggregation is advanced into the future on a fixed
grid to prevent clock drift. So when an aggregation runs after some idle
period, we can not just set it to "now + psi_period", but have to
calculate the downtime and advance the target time relative to itself.
However, if the aggregator was disabled exactly one psi_period (ns), we
drop one idle period in the calculation due to a > when we should do >=.
In that case, next_update will be advanced from 'now - psi_period' to
'now' when it should be moved to 'now + psi_period'. The run finishes
with last_update == next_update == sched_clock().
With hardware clocks, this exact nanosecond match isn't likely in the
first place; but if it does happen, the clock will still have moved on and
the period non-zero by the time the worker runs. A pointlessly short
period, but besides the extra work, no harm no foul. However, a slow
sched_clock() like we have on VMs might not have advanced either by the
time the worker runs again. And when we calculate the elapsed period, the
result, our pressure divisor, will be 0. Ouch.
Fix this by correctly handling the situation when the elapsed time between
aggregation runs is precisely two periods, and advance the expiration
timestamp correctly to period into the future.
Link: http://lkml.kernel.org/r/20190214193157.15788-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Łukasz Siudut <lsiudut@fb.com
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull networking fixes from David Miller:
1) Fix suspend and resume in mt76x0u USB driver, from Stanislaw
Gruszka.
2) Missing memory barriers in xsk, from Magnus Karlsson.
3) rhashtable fixes in mac80211 from Herbert Xu.
4) 32-bit MIPS eBPF JIT fixes from Paul Burton.
5) Fix for_each_netdev_feature() on big endian, from Hauke Mehrtens.
6) GSO validation fixes from Willem de Bruijn.
7) Endianness fix for dwmac4 timestamp handling, from Alexandre Torgue.
8) More strict checks in tcp_v4_err(), from Eric Dumazet.
9) af_alg_release should NULL out the sk after the sock_put(), from Mao
Wenan.
10) Missing unlock in mac80211 mesh error path, from Wei Yongjun.
11) Missing device put in hns driver, from Salil Mehta.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (44 commits)
sky2: Increase D3 delay again
vhost: correctly check the return value of translate_desc() in log_used()
net: netcp: Fix ethss driver probe issue
net: hns: Fixes the missing put_device in positive leg for roce reset
net: stmmac: Fix a race in EEE enable callback
qed: Fix iWARP syn packet mac address validation.
qed: Fix iWARP buffer size provided for syn packet processing.
r8152: Add support for MAC address pass through on RTL8153-BD
mac80211: mesh: fix missing unlock on error in table_path_del()
net/mlx4_en: fix spelling mistake: "quiting" -> "quitting"
net: crypto set sk to NULL when af_alg_release.
net: Do not allocate page fragments that are not skb aligned
mm: Use fixed constant in page_frag_alloc instead of size + 1
tcp: tcp_v4_err() should be more careful
tcp: clear icsk_backoff in tcp_write_queue_purge()
net: mv643xx_eth: disable clk on error path in mv643xx_eth_shared_probe()
qmi_wwan: apply SET_DTR quirk to Sierra WP7607
net: stmmac: handle endianness in dwmac4_get_timestamp
doc: Mention MSG_ZEROCOPY implementation for UDP
mlxsw: __mlxsw_sp_port_headroom_set(): Fix a use of local variable
...
- Have kprobes not use copy_from_user() to access kernel addresses,
because kprobes can legitimately poke at bad kernel memory, which
will fault. Copy from user code should never fault in kernel space.
Using probe_mem_read() can handle kernel address space faulting.
- Put back the entries counter in the tracing output that was accidentally
removed.
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Merge tag 'trace-v5.0-rc4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"Two more tracing fixes
- Have kprobes not use copy_from_user() to access kernel addresses,
because kprobes can legitimately poke at bad kernel memory, which
will fault. Copy from user code should never fault in kernel space.
Using probe_mem_read() can handle kernel address space faulting.
- Put back the entries counter in the tracing output that was
accidentally removed"
* tag 'trace-v5.0-rc4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix number of entries in trace header
kprobe: Do not use uaccess functions to access kernel memory that can fault
Pull perf fixes from Ingo Molnar:
"Two fixes on the kernel side: fix an over-eager condition that failed
larger perf ring-buffer sizes, plus fix crashes in the Intel BTS code
for a corner case, found by fuzzing"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Fix impossible ring-buffer sizes warning
perf/x86: Add check_period PMU callback
Alexei Starovoitov says:
====================
pull-request: bpf 2019-02-16
The following pull-request contains BPF updates for your *net* tree.
The main changes are:
1) fix lockdep false positive in bpf_get_stackid(), from Alexei.
2) several AF_XDP fixes, from Bjorn, Magnus, Davidlohr.
3) fix narrow load from struct bpf_sock, from Martin.
4) mips JIT fixes, from Paul.
5) gso handling fix in bpf helpers, from Willem.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The following commit
441dae8f2f ("tracing: Add support for display of tgid in trace output")
removed the call to print_event_info() from print_func_help_header_irq()
which results in the ftrace header not reporting the number of entries
written in the buffer. As this wasn't the original intent of the patch,
re-introduce the call to print_event_info() to restore the orginal
behaviour.
Link: http://lkml.kernel.org/r/20190214152950.4179-1-quentin.perret@arm.com
Acked-by: Joel Fernandes <joelaf@google.com>
Cc: stable@vger.kernel.org
Fixes: 441dae8f2f ("tracing: Add support for display of tgid in trace output")
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pull signal fix from Eric Biederman:
"Just a single patch that restores PTRACE_EVENT_EXIT functionality that
was accidentally broken by last weeks fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
signal: Restore the stop PTRACE_EVENT_EXIT
it processes the args but does not update the remaining length
of the buffer that the string arguments will be placed in. It
constantly passes in the total size of buffer used instead of
passing in the remaining size of the buffer used. This could cause
issues if the strings are larger than the max size of an event
which could cause the strings to be written beyond what was reserved
on the buffer.
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Merge tag 'trace-v5.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fix from Steven Rostedt:
"This fixes kprobes/uprobes dynamic processing of strings, where it
processes the args but does not update the remaining length of the
buffer that the string arguments will be placed in. It constantly
passes in the total size of buffer used instead of passing in the
remaining size of the buffer used.
This could cause issues if the strings are larger than the max size of
an event which could cause the strings to be written beyond what was
reserved on the buffer"
* tag 'trace-v5.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: probeevent: Correctly update remaining space in dynamic area
In the middle of do_exit() there is there is a call
"ptrace_event(PTRACE_EVENT_EXIT, code);" That call places the process
in TACKED_TRACED aka "(TASK_WAKEKILL | __TASK_TRACED)" and waits for
for the debugger to release the task or SIGKILL to be delivered.
Skipping past dequeue_signal when we know a fatal signal has already
been delivered resulted in SIGKILL remaining pending and
TIF_SIGPENDING remaining set. This in turn caused the
scheduler to not sleep in PTACE_EVENT_EXIT as it figured
a fatal signal was pending. This also caused ptrace_freeze_traced
in ptrace_check_attach to fail because it left a per thread
SIGKILL pending which is what fatal_signal_pending tests for.
This difference in signal state caused strace to report
strace: Exit of unknown pid NNNNN ignored
Therefore update the signal handling state like dequeue_signal
would when removing a per thread SIGKILL, by removing SIGKILL
from the per thread signal mask and clearing TIF_SIGPENDING.
Acked-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Ivan Delalande <colona@arista.com>
Cc: stable@vger.kernel.org
Fixes: 35634ffa17 ("signal: Always notice exiting tasks")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Some lockdep functions can be involved in breakpoint handling
and probing on those functions can cause a breakpoint recursion.
Prohibit probing on those functions by blacklist.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrea Righi <righi.andrea@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/154998810578.31052.1680977921449292812.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Newer GCC versions can generate some different instances of a function
with suffixed symbols if the function is optimized and only
has a part of that. (e.g. .constprop, .part etc.)
In this case, it is not enough to check the entry of kprobe
blacklist because it only records non-suffixed symbol address.
To fix this issue, search non-suffixed symbol in blacklist if
given address is within a symbol which has a suffix.
Note that this can cause false positive cases if a kprobe-safe
function is optimized to suffixed instance and has same name
symbol which is blacklisted.
But I would like to chose a fail-safe design for this issue.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrea Righi <righi.andrea@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/154998799234.31052.6136378903570418008.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Prohibit probing on the functions called before kprobe_int3_handler()
in do_int3(). More specifically, ftrace_int3_handler(),
poke_int3_handler(), and ist_enter(). And since rcu_nmi_enter() is
called by ist_enter(), it also should be marked as NOKPROBE_SYMBOL.
Since those are handled before kprobe_int3_handler(), probing those
functions can cause a breakpoint recursion and crash the kernel.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrea Righi <righi.andrea@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/154998793571.31052.11301258949601150994.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The following commit:
9dff0aa95a ("perf/core: Don't WARN() for impossible ring-buffer sizes")
results in perf recording failures with larger mmap areas:
root@skl:/tmp# perf record -g -a
failed to mmap with 12 (Cannot allocate memory)
The root cause is that the following condition is buggy:
if (order_base_2(size) >= MAX_ORDER)
goto fail;
The problem is that @size is in bytes and MAX_ORDER is in pages,
so the right test is:
if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)
goto fail;
Fix it.
Reported-by: "Jin, Yao" <yao.jin@linux.intel.com>
Bisected-by: Borislav Petkov <bp@alien8.de>
Analyzed-by: Peter Zijlstra <peterz@infradead.org>
Cc: Julien Thierry <julien.thierry@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>
Fixes: 9dff0aa95a ("perf/core: Don't WARN() for impossible ring-buffer sizes")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 9178412ddf ("tracing: probeevent: Return consumed
bytes of dynamic area") improved the string fetching
mechanism by returning the number of required bytes after
copying the argument to the dynamic area. However, this
return value is now only used to increment the pointer
inside the dynamic area but misses updating the 'maxlen'
variable which indicates the remaining space in the dynamic
area.
This means that fetch_store_string() always reads the *total*
size of the dynamic area from the data_loc pointer instead of
the *remaining* size (and passes it along to
strncpy_from_{user,unsafe}) even if we're already about to
copy data into the middle of the dynamic area.
Link: http://lkml.kernel.org/r/20190206190013.16405-1-andreas.ziegler@fau.de
Cc: Ingo Molnar <mingo@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 9178412ddf ("tracing: probeevent: Return consumed bytes of dynamic area")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Andreas Ziegler <andreas.ziegler@fau.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Vince (and later on Ravi) reported crashes in the BTS code during
fuzzing with the following backtrace:
general protection fault: 0000 [#1] SMP PTI
...
RIP: 0010:perf_prepare_sample+0x8f/0x510
...
Call Trace:
<IRQ>
? intel_pmu_drain_bts_buffer+0x194/0x230
intel_pmu_drain_bts_buffer+0x160/0x230
? tick_nohz_irq_exit+0x31/0x40
? smp_call_function_single_interrupt+0x48/0xe0
? call_function_single_interrupt+0xf/0x20
? call_function_single_interrupt+0xa/0x20
? x86_schedule_events+0x1a0/0x2f0
? x86_pmu_commit_txn+0xb4/0x100
? find_busiest_group+0x47/0x5d0
? perf_event_set_state.part.42+0x12/0x50
? perf_mux_hrtimer_restart+0x40/0xb0
intel_pmu_disable_event+0xae/0x100
? intel_pmu_disable_event+0xae/0x100
x86_pmu_stop+0x7a/0xb0
x86_pmu_del+0x57/0x120
event_sched_out.isra.101+0x83/0x180
group_sched_out.part.103+0x57/0xe0
ctx_sched_out+0x188/0x240
ctx_resched+0xa8/0xd0
__perf_event_enable+0x193/0x1e0
event_function+0x8e/0xc0
remote_function+0x41/0x50
flush_smp_call_function_queue+0x68/0x100
generic_smp_call_function_single_interrupt+0x13/0x30
smp_call_function_single_interrupt+0x3e/0xe0
call_function_single_interrupt+0xf/0x20
</IRQ>
The reason is that while event init code does several checks
for BTS events and prevents several unwanted config bits for
BTS event (like precise_ip), the PERF_EVENT_IOC_PERIOD allows
to create BTS event without those checks being done.
Following sequence will cause the crash:
If we create an 'almost' BTS event with precise_ip and callchains,
and it into a BTS event it will crash the perf_prepare_sample()
function because precise_ip events are expected to come
in with callchain data initialized, but that's not the
case for intel_pmu_drain_bts_buffer() caller.
Adding a check_period callback to be called before the period
is changed via PERF_EVENT_IOC_PERIOD. It will deny the change
if the event would become BTS. Plus adding also the limit_period
check as well.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20190204123532.GA4794@krava
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull perf fixes from Ingo Molnar:
"A couple of kernel side fixes:
- Fix the Intel uncore driver on certain hardware configurations
- Fix a CPU hotplug related memory allocation bug
- Remove a spurious WARN()
... plus also a handful of perf tooling fixes"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf script python: Add Python3 support to tests/attr.py
perf trace: Support multiple "vfs_getname" probes
perf symbols: Filter out hidden symbols from labels
perf symbols: Add fallback definitions for GELF_ST_VISIBILITY()
tools headers uapi: Sync linux/in.h copy from the kernel sources
perf clang: Do not use 'return std::move(something)'
perf mem/c2c: Fix perf_mem_events to support powerpc
perf tests evsel-tp-sched: Fix bitwise operator
perf/core: Don't WARN() for impossible ring-buffer sizes
perf/x86/intel: Delay memory deallocation until x86_pmu_dead_cpu()
perf/x86/intel/uncore: Add Node ID mask
Pull signal fixes from Eric Biederman:
"This contains four small fixes for signal handling. A missing range
check, a regression fix, prioritizing signals we have already started
a signal group exit for, and better detection of synchronous signals.
The confused decision of which signals to handle failed spectacularly
when a timer was pointed at SIGBUS and the stack overflowed. Resulting
in an unkillable process in an infinite loop instead of a SIGSEGV and
core dump"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
signal: Better detection of synchronous signals
signal: Always notice exiting tasks
signal: Always attempt to allocate siginfo for SIGSTOP
signal: Make siginmask safe when passed a signal of 0
Pull networking fixes from David Miller:
"This pull request is dedicated to the upcoming snowpocalypse parts 2
and 3 in the Pacific Northwest:
1) Drop profiles are broken because some drivers use dev_kfree_skb*
instead of dev_consume_skb*, from Yang Wei.
2) Fix IWLWIFI kconfig deps, from Luca Coelho.
3) Fix percpu maps updating in bpftool, from Paolo Abeni.
4) Missing station release in batman-adv, from Felix Fietkau.
5) Fix some networking compat ioctl bugs, from Johannes Berg.
6) ucc_geth must reset the BQL queue state when stopping the device,
from Mathias Thore.
7) Several XDP bug fixes in virtio_net from Toshiaki Makita.
8) TSO packets must be sent always on queue 0 in stmmac, from Jose
Abreu.
9) Fix socket refcounting bug in RDS, from Eric Dumazet.
10) Handle sparse cpu allocations in bpf selftests, from Martynas
Pumputis.
11) Make sure mgmt frames have enough tailroom in mac80211, from Felix
Feitkau.
12) Use safe list walking in sctp_sendmsg() asoc list traversal, from
Greg Kroah-Hartman.
13) Make DCCP's ccid_hc_[rt]x_parse_options always check for NULL
ccid, from Eric Dumazet.
14) Need to reload WoL password into bcmsysport device after deep
sleeps, from Florian Fainelli.
15) Remove filter from mask before freeing in cls_flower, from Petr
Machata.
16) Missing release and use after free in error paths of s390 qeth
code, from Julian Wiedmann.
17) Fix lockdep false positive in dsa code, from Marc Zyngier.
18) Fix counting of ATU violations in mv88e6xxx, from Andrew Lunn.
19) Fix EQ firmware assert in qed driver, from Manish Chopra.
20) Don't default Caivum PTP to Y in kconfig, from Bjorn Helgaas"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (116 commits)
net: dsa: b53: Fix for failure when irq is not defined in dt
sit: check if IPv6 enabled before calling ip6_err_gen_icmpv6_unreach()
geneve: should not call rt6_lookup() when ipv6 was disabled
net: Don't default Cavium PTP driver to 'y'
net: broadcom: replace dev_kfree_skb_irq by dev_consume_skb_irq for drop profiles
net: via-velocity: replace dev_kfree_skb_irq by dev_consume_skb_irq for drop profiles
net: tehuti: replace dev_kfree_skb_irq by dev_consume_skb_irq for drop profiles
net: sun: replace dev_kfree_skb_irq by dev_consume_skb_irq for drop profiles
net: fsl_ucc_hdlc: replace dev_kfree_skb_irq by dev_consume_skb_irq for drop profiles
net: fec_mpc52xx: replace dev_kfree_skb_irq by dev_consume_skb_irq for drop profiles
net: smsc: epic100: replace dev_kfree_skb_irq by dev_consume_skb_irq for drop profiles
net: dscc4: replace dev_kfree_skb_irq by dev_consume_skb_irq for drop profiles
net: tulip: de2104x: replace dev_kfree_skb_irq by dev_consume_skb_irq for drop profiles
net: defxx: replace dev_kfree_skb_irq by dev_consume_skb_irq for drop profiles
net/mlx5e: Don't overwrite pedit action when multiple pedit used
net/mlx5e: Update hw flows when encap source mac changed
qed*: Advance drivers version to 8.37.0.20
qed: Change verbosity for coalescing message.
qede: Fix system crash on configuring channels.
qed: Consider TX tcs while deriving the max num_queues for PF.
...
Here are some driver core fixes for 5.0-rc6.
Well, not so much "driver core" as "debugfs". There's a lot of
outstanding debugfs cleanup patches coming in through different
subsystem trees, and in that process the debugfs core was found that it
really should return errors when something bad happens, to prevent
random files from showing up in the root of debugfs afterward. So
debugfs was fixed up to handle this properly, and then two fixes for
the relay and blk-mq code was needed as it was making invalid
assumptions about debugfs return values.
There's also a cacheinfo fix in here that resolves a tiny issue.
All of these have been in linux-next for over a week with no reported
problems.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-5.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core fixes from Greg KH:
"Here are some driver core fixes for 5.0-rc6.
Well, not so much "driver core" as "debugfs". There's a lot of
outstanding debugfs cleanup patches coming in through different
subsystem trees, and in that process the debugfs core was found that
it really should return errors when something bad happens, to prevent
random files from showing up in the root of debugfs afterward. So
debugfs was fixed up to handle this properly, and then two fixes for
the relay and blk-mq code was needed as it was making invalid
assumptions about debugfs return values.
There's also a cacheinfo fix in here that resolves a tiny issue.
All of these have been in linux-next for over a week with no reported
problems"
* tag 'driver-core-5.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
blk-mq: protect debugfs_create_files() from failures
relay: check return of create_buf_file() properly
debugfs: debugfs_lookup() should return NULL if not found
debugfs: return error values, not NULL
debugfs: fix debugfs_rename parameter checking
cacheinfo: Keep the old value if of_property_read_u32 fails
commit 56222b212e ("futex: Drop hb->lock before enqueueing on the
rtmutex") changed the locking rules in the futex code so that the hash
bucket lock is not longer held while the waiter is enqueued into the
rtmutex wait list. This made the lock and the unlock path symmetric, but
unfortunately the possible early exit from __rt_mutex_proxy_start() due to
a detected deadlock was not updated accordingly. That allows a concurrent
unlocker to observe inconsitent state which triggers the warning in the
unlock path.
futex_lock_pi() futex_unlock_pi()
lock(hb->lock)
queue(hb_waiter) lock(hb->lock)
lock(rtmutex->wait_lock)
unlock(hb->lock)
// acquired hb->lock
hb_waiter = futex_top_waiter()
lock(rtmutex->wait_lock)
__rt_mutex_proxy_start()
---> fail
remove(rtmutex_waiter);
---> returns -EDEADLOCK
unlock(rtmutex->wait_lock)
// acquired wait_lock
wake_futex_pi()
rt_mutex_next_owner()
--> returns NULL
--> WARN
lock(hb->lock)
unqueue(hb_waiter)
The problem is caused by the remove(rtmutex_waiter) in the failure case of
__rt_mutex_proxy_start() as this lets the unlocker observe a waiter in the
hash bucket but no waiter on the rtmutex, i.e. inconsistent state.
The original commit handles this correctly for the other early return cases
(timeout, signal) by delaying the removal of the rtmutex waiter until the
returning task reacquired the hash bucket lock.
Treat the failure case of __rt_mutex_proxy_start() in the same way and let
the existing cleanup code handle the eventual handover of the rtmutex
gracefully. The regular rt_mutex_proxy_start() gains the rtmutex waiter
removal for the failure case, so that the other callsites are still
operating correctly.
Add proper comments to the code so all these details are fully documented.
Thanks to Peter for helping with the analysis and writing the really
valuable code comments.
Fixes: 56222b212e ("futex: Drop hb->lock before enqueueing on the rtmutex")
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Co-developed-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Stefan Liebler <stli@linux.ibm.com>
Cc: Sebastian Sewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1901292311410.1950@nanos.tec.linutronix.de
The current comment for the barrier that guarantees that waiter increment
is always before taking the hb spinlock (barrier (A)) needs to be fixed as
it is misplaced.
This is obviously referring to hb_waiters_inc, which is a full barrier.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190206185602.949-1-dave@stgolabs.net
Recently syzkaller was able to create unkillablle processes by
creating a timer that is delivered as a thread local signal on SIGHUP,
and receiving SIGHUP SA_NODEFERER. Ultimately causing a loop failing
to deliver SIGHUP but always trying.
When the stack overflows delivery of SIGHUP fails and force_sigsegv is
called. Unfortunately because SIGSEGV is numerically higher than
SIGHUP next_signal tries again to deliver a SIGHUP.
From a quality of implementation standpoint attempting to deliver the
timer SIGHUP signal is wrong. We should attempt to deliver the
synchronous SIGSEGV signal we just forced.
We can make that happening in a fairly straight forward manner by
instead of just looking at the signal number we also look at the
si_code. In particular for exceptions (aka synchronous signals) the
si_code is always greater than 0.
That still has the potential to pick up a number of asynchronous
signals as in a few cases the same si_codes that are used
for synchronous signals are also used for asynchronous signals,
and SI_KERNEL is also included in the list of possible si_codes.
Still the heuristic is much better and timer signals are definitely
excluded. Which is enough to prevent all known ways for someone
sending a process signals fast enough to cause unexpected and
arguably incorrect behavior.
Cc: stable@vger.kernel.org
Fixes: a27341cd5f ("Prioritize synchronous signals over 'normal' signals")
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Recently syzkaller was able to create unkillablle processes by
creating a timer that is delivered as a thread local signal on SIGHUP,
and receiving SIGHUP SA_NODEFERER. Ultimately causing a loop
failing to deliver SIGHUP but always trying.
Upon examination it turns out part of the problem is actually most of
the solution. Since 2.5 signal delivery has found all fatal signals,
marked the signal group for death, and queued SIGKILL in every threads
thread queue relying on signal->group_exit_code to preserve the
information of which was the actual fatal signal.
The conversion of all fatal signals to SIGKILL results in the
synchronous signal heuristic in next_signal kicking in and preferring
SIGHUP to SIGKILL. Which is especially problematic as all
fatal signals have already been transformed into SIGKILL.
Instead of dequeueing signals and depending upon SIGKILL to
be the first signal dequeued, first test if the signal group
has already been marked for death. This guarantees that
nothing in the signal queue can prevent a process that needs
to exit from exiting.
Cc: stable@vger.kernel.org
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Ref: ebf5ebe31d2c ("[PATCH] signal-fixes-2.5.59-A4")
History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
- Cut and paste fix to have uprobe printks say "uprobe" and not "kprobe"
- Add terminating '\0' byte when copying of function arguments
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Merge tag 'trace-v5.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"This has two fixes for uprobe code.
- Cut and paste fix to have uprobe printks say "uprobe" and not
"kprobe"
- Add terminating '\0' byte when copying function arguments"
* tag 'trace-v5.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing/uprobes: Fix output for multiple string arguments
tracing: uprobes: Fix typo in pr_fmt string
When pmu::setup_aux() is called the coresight PMU needs to know which
sink to use for the session by looking up the information in the
event's attr::config2 field.
As such simply replace the cpu information by the complete perf_event
structure and change all affected customers.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki Poulouse <suzuki.poulose@arm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Link: http://lkml.kernel.org/r/20190131184714.20388-2-mathieu.poirier@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Since 2.5.34 the code has had the potential to not allocate siginfo
for SIGSTOP signals. Except for ptrace this is perfectly fine as only
ptrace can use PTRACE_PEEK_SIGINFO and see what the contents of
the delivered siginfo are.
Users of PTRACE_PEEK_SIGINFO that care about the contents siginfo
for SIGSTOP are rare, but they do exist. A seccomp self test
has cared and lldb cares.
Jack Andersen <jackoalan@gmail.com> writes:
> The patch titled
> `signal: Never allocate siginfo for SIGKILL or SIGSTOP`
> created a regression for users of PTRACE_GETSIGINFO needing to
> discern signals that were raised via the tgkill syscall.
>
> A notable user of this tgkill+ptrace combination is lldb while
> debugging a multithreaded program. Without the ability to detect a
> SIGSTOP originating from tgkill, lldb does not have a way to
> synchronize on a per-thread basis and falls back to SIGSTOP-ing the
> entire process.
Everyone affected by this please note. The kernel can still fail to
allocate a siginfo structure. The allocation is with GFP_KERNEL and
is best effort only. If memory is tight when the signal allocation
comes in this will fail to allocate a siginfo.
So I strongly recommend looking at more robust solutions for
synchronizing with a single thread such as PTRACE_INTERRUPT. Or if
that does not work persuading your friendly local kernel developer to
build the interface you need.
Reported-by: Tycho Andersen <tycho@tycho.ws>
Reported-by: Kees Cook <keescook@chromium.org>
Reported-by: Jack Andersen <jackoalan@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Christian Brauner <christian@brauner.io>
Cc: stable@vger.kernel.org
Fixes: f149b31557 ("signal: Never allocate siginfo for SIGKILL or SIGSTOP")
Fixes: 6dfc88977e42 ("[PATCH] shared thread signals")
History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable ring_buffer.aux_refcount is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
** Important note for maintainers:
Some functions from refcount_t API defined in lib/refcount.c
have different memory ordering guarantees than their atomic
counterparts. Please check Documentation/core-api/refcount-vs-atomic.rst
for more information.
Normally the differences should not matter since refcount_t provides
enough guarantees to satisfy the refcounting use cases, but in
some rare cases it might matter.
Please double check that you don't have some undocumented
memory guarantees for this variable usage.
For the ring_buffer.aux_refcount it might make a difference
in following places:
- perf_aux_output_begin(): increment in refcount_inc_not_zero() only
guarantees control dependency on success vs. fully ordered
atomic counterpart
- rb_free_aux(): decrement in refcount_dec_and_test() only
provides RELEASE ordering and ACQUIRE ordering + control dependency
on success vs. fully ordered atomic counterpart
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: namhyung@kernel.org
Link: https://lkml.kernel.org/r/1548678448-24458-4-git-send-email-elena.reshetova@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable ring_buffer.refcount is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
** Important note for maintainers:
Some functions from refcount_t API defined in lib/refcount.c
have different memory ordering guarantees than their atomic
counterparts. Please check Documentation/core-api/refcount-vs-atomic.rst
for more information.
Normally the differences should not matter since refcount_t provides
enough guarantees to satisfy the refcounting use cases, but in
some rare cases it might matter.
Please double check that you don't have some undocumented
memory guarantees for this variable usage.
For the ring_buffer.refcount it might make a difference
in following places:
- ring_buffer_get(): increment in refcount_inc_not_zero() only
guarantees control dependency on success vs. fully ordered
atomic counterpart
- ring_buffer_put(): decrement in refcount_dec_and_test() only
provides RELEASE ordering and ACQUIRE ordering + control dependency
on success vs. fully ordered atomic counterpart
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: namhyung@kernel.org
Link: https://lkml.kernel.org/r/1548678448-24458-3-git-send-email-elena.reshetova@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable perf_event_context.refcount is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
** Important note for maintainers:
Some functions from refcount_t API defined in lib/refcount.c
have different memory ordering guarantees than their atomic
counterparts. Please check Documentation/core-api/refcount-vs-atomic.rst
for more information.
Normally the differences should not matter since refcount_t provides
enough guarantees to satisfy the refcounting use cases, but in
some rare cases it might matter.
Please double check that you don't have some undocumented
memory guarantees for this variable usage.
For the perf_event_context.refcount it might make a difference
in following places:
- get_ctx(), perf_event_ctx_lock_nested(), perf_lock_task_context()
and __perf_event_ctx_lock_double(): increment in
refcount_inc_not_zero() only guarantees control dependency
on success vs. fully ordered atomic counterpart
- put_ctx(): decrement in refcount_dec_and_test() provides
RELEASE ordering and ACQUIRE ordering + control dependency on success
vs. fully ordered atomic counterpart
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: namhyung@kernel.org
Link: https://lkml.kernel.org/r/1548678448-24458-2-git-send-email-elena.reshetova@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Replace the license boiler plate with a SPDX license identifier.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paul McKenney <paulmck@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190116111308.211981422@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Use proper SPDX license identifiers instead of the bogus reference to
kernel-base/COPYING.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190116111308.012666937@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The perf tool uses /proc/sys/kernel/perf_event_mlock_kb to determine how
large its ringbuffer mmap should be. This can be configured to arbitrary
values, which can be larger than the maximum possible allocation from
kmalloc.
When this is configured to a suitably large value (e.g. thanks to the
perf fuzzer), attempting to use perf record triggers a WARN_ON_ONCE() in
__alloc_pages_nodemask():
WARNING: CPU: 2 PID: 5666 at mm/page_alloc.c:4511 __alloc_pages_nodemask+0x3f8/0xbc8
Let's avoid this by checking that the requested allocation is possible
before calling kzalloc.
Reported-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20190110142745.25495-1-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull cpu hotplug fixes from Thomas Gleixner:
"Two fixes for the cpu hotplug machinery:
- Replace the overly clever 'SMT disabled by BIOS' detection logic as
it breaks KVM scenarios and prevents speculation control updates
when the Hyperthreads are brought online late after boot.
- Remove a redundant invocation of the speculation control update
function"
* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM
x86/speculation: Remove redundant arch_smt_update() invocation
Gustavo A. R. Silva