Peter Zijlstra 3ee8e109c3 perf: Fix sys_perf_event_open() race against self ... commit 3ac6487e584a1eb54071dbe1212e05b884136704 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-05-25 09:17:55 +02:00
..
callchain.c	uaccess: add force_uaccess_{begin,end} helpers	2020-08-12 10:57:59 -07:00
core.c	perf: Fix sys_perf_event_open() race against self	2022-05-25 09:17:55 +02:00
hw_breakpoint.c
internal.h	perf/core: Fix perf_mmap fail when CONFIG_PERF_USE_VMALLOC enabled	2022-04-27 13:53:56 +02:00
Makefile
ring_buffer.c	perf/core: Fix perf_mmap fail when CONFIG_PERF_USE_VMALLOC enabled	2022-04-27 13:53:56 +02:00
uprobes.c	kernel: delete repeated words in comments	2022-02-01 17:25:45 +01:00