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| author | Peter Zijlstra <peterz@infradead.org> | 2022-05-20 20:38:06 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-20 08:44:00 -1000 |
| commit | 3ac6487e584a1eb54071dbe1212e05b884136704 (patch) | |
| tree | 07b3b0617e264ae3ef5d188275e7991120859ee2 /kernel/tsacct.c | |
| parent | 3b5e1590a26713a8c76896f0f1b99f52ec24e72f (diff) | |
| download | linux-next-3ac6487e584a1eb54071dbe1212e05b884136704.tar.gz | |
perf: Fix sys_perf_event_open() race against self
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: f63a8daa5812 ("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>
Diffstat (limited to 'kernel/tsacct.c')
0 files changed, 0 insertions, 0 deletions