Marco Elver 26ab08df86 perf: Fix data race between pin_count increment/decrement ... commit 6c605f8371 upstream. KCSAN reports a data race between increment and decrement of pin_count: write to 0xffff888237c2d4e0 of 4 bytes by task 15740 on cpu 1: find_get_context kernel/events/core.c:4617 __do_sys_perf_event_open kernel/events/core.c:12097 [inline] __se_sys_perf_event_open kernel/events/core.c:11933 ... read to 0xffff888237c2d4e0 of 4 bytes by task 15743 on cpu 0: perf_unpin_context kernel/events/core.c:1525 [inline] __do_sys_perf_event_open kernel/events/core.c:12328 [inline] __se_sys_perf_event_open kernel/events/core.c:11933 ... Because neither read-modify-write here is atomic, this can lead to one of the operations being lost, resulting in an inconsistent pin_count. Fix it by adding the missing locking in the CPU-event case. Fixes: fe4b04fa31 ("perf: Cure task_oncpu_function_call() races") Reported-by: syzbot+142c9018f5962db69c7e@syzkaller.appspotmail.com Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20210527104711.2671610-1-elver@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2021-06-16 11:59:44 +02:00
..
callchain.c	perf/core: Convert to SPDX license identifiers	2019-02-04 08:46:11 +01:00
core.c	perf: Fix data race between pin_count increment/decrement	2021-06-16 11:59:44 +02:00
hw_breakpoint.c	perf/hw_breakpoint: Fix arch_hw_breakpoint use-before-initialization	2019-09-06 08:24:01 +02:00
internal.h	perf: Fix get_recursion_context()	2020-11-18 19:20:28 +01:00
Makefile
ring_buffer.c	perf/ring-buffer: Use regular variables for nesting	2019-05-24 09:00:11 +02:00
uprobes.c	uprobes: __replace_page() avoid BUG in munlock_vma_page()	2020-08-26 10:40:51 +02:00