Peter Zijlstra 1e450e34ef perf: Fix sys_perf_event_open() race against self ... commit 3ac6487e58 upstream. Norbert reported that it's possible to race sys_perf_event_open() such that the looser ends up in another context from the group leader, triggering many WARNs. The move_group case checks for races against itself, but the !move_group case doesn't, seemingly relying on the previous group_leader->ctx == ctx check. However, that check is racy due to not holding any locks at that time. Therefore, re-check the result after acquiring locks and bailing if they no longer match. Additionally, clarify the not_move_group case from the move_group-vs-move_group race. Fixes: f63a8daa58 ("perf: Fix event->ctx locking") Reported-by: Norbert Slusarek <nslusarek@gmx.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Tao Wu <tallwu@tencent.com> Reviewed-by: Alex Shi <alexsshi@tencent.com>		2024-06-11 20:41:41 +08:00
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Makefile	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
callchain.c	ock: sync codes to ock 5.4.119-20.0009.21	2024-06-11 20:27:38 +08:00
core.c	perf: Fix sys_perf_event_open() race against self	2024-06-11 20:41:41 +08:00
hw_breakpoint.c	perf/hw_breakpoint: Fix arch_hw_breakpoint use-before-initialization	2019-09-06 08:24:01 +02:00
internal.h	ock: sync codes to ock 5.4.119-20.0009.21	2024-06-11 20:27:38 +08:00
ring_buffer.c	perf/ring-buffer: Use regular variables for nesting	2019-05-24 09:00:11 +02:00
uprobes.c	ock: sync codes to ock 5.4.119-20.0009.21	2024-06-11 20:27:38 +08:00