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authorPeter Zijlstra2016-02-24 18:45:42 +0100
committerIngo Molnar2016-02-25 08:42:33 +0100
commita4f4bb6d0c69d0bb573f1d9e6f1b806f9b038b19 (patch)
treed6f0fb9d98cf14837637b2c3d26d3605944d487e /kernel/events
parent130056275ade730e7a79c110212c8815202773ee (diff)
perf: Allow perf_release() with !event->ctx
In the err_file: fput(event_file) case, the event will not yet have been attached to a context. However perf_release() does assume it has been. Cure this. Tested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dvyukov@google.com Cc: eranian@google.com Cc: oleg@redhat.com Cc: panand@redhat.com Cc: sasha.levin@oracle.com Cc: vince@deater.net Link: http://lkml.kernel.org/r/20160224174947.793996260@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 211a5ce64e3f..d5299e2e435d 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3754,9 +3754,19 @@ static void put_event(struct perf_event *event)
*/
int perf_event_release_kernel(struct perf_event *event)
{
- struct perf_event_context *ctx;
+ struct perf_event_context *ctx = event->ctx;
struct perf_event *child, *tmp;
+ /*
+ * If we got here through err_file: fput(event_file); we will not have
+ * attached to a context yet.
+ */
+ if (!ctx) {
+ WARN_ON_ONCE(event->attach_state &
+ (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
+ goto no_ctx;
+ }
+
if (!is_kernel_event(event))
perf_remove_from_owner(event);
@@ -3832,8 +3842,8 @@ again:
}
mutex_unlock(&event->child_mutex);
- /* Must be the last reference */
- put_event(event);
+no_ctx:
+ put_event(event); /* Must be the 'last' reference */
return 0;
}
EXPORT_SYMBOL_GPL(perf_event_release_kernel);