diff options
| author | Amulya Y <ayarlagadda@nvidia.com> | 2018-04-06 15:42:31 -0700 |
|---|---|---|
| committer | Winnie Hsu <whsu@nvidia.com> | 2018-04-19 10:58:33 -0700 |
| commit | ac43b10b632fac3412f18100e463e2129318bd3a (patch) | |
| tree | 2820113616dc252ba2abbaeb6789c57d95fad595 /kernel | |
| parent | 6b8d6d331daaa7d2118fdd61eac514363e0625e7 (diff) | |
perf: Fix race in swevent hash
There's a race on CPU unplug where we free the swevent hash array
while it can still have events on. This will result in a
use-after-free which is BAD.
Simply do not free the hash array on unplug. This leaves the thing
around and no use-after-free takes place.
When the last swevent dies, we do a for_each_possible_cpu() iteration
anyway to clean these up, at which time we'll free it, so no leakage
will occur.
Bug 1823317
But 1935735
Change-Id: I309528873f8576f96663afbe51ce2739934df16c
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Gagan Grover <ggrover@nvidia.com>
Signed-off-by: Amulya Yarlagadda <ayarlagadda@nvidia.com>
Reviewed-on: http://git-master/r/1259934
(cherry picked from commit 5ea640855404df656d94bfa3990d8eba2b5f90f9)
Reviewed-on: https://git-master.nvidia.com/r/1690284
GVS: Gerrit_Virtual_Submit
Reviewed-by: Bibek Basu <bbasu@nvidia.com>
Reviewed-by: Winnie Hsu <whsu@nvidia.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/core.c | 6 |
1 files changed, 0 insertions, 6 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index f8eb2b154bdb..be3b4cc87eeb 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7450,13 +7450,7 @@ static void perf_event_exit_cpu_context(int cpu) static void perf_event_exit_cpu(int cpu) { - struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); - perf_event_exit_cpu_context(cpu); - - mutex_lock(&swhash->hlist_mutex); - swevent_hlist_release(swhash); - mutex_unlock(&swhash->hlist_mutex); } #else static inline void perf_event_exit_cpu(int cpu) { } |