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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>
This commit is contained in:
Peter Zijlstra 2016-02-24 18:45:42 +01:00 committed by Ingo Molnar
parent 130056275a
commit a4f4bb6d0c
1 changed files with 13 additions and 3 deletions
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16
kernel/events/core.c
View File

@ -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);