perf: Do not double free

commit 130056275ade730e7a79c110212c8815202773ee upstream.

In case of: err_file: fput(event_file), we'll end up calling
perf_release() which in turn will free the event.

Do not then free the event _again_.

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/20160224174947.697350349@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/kernel/events/core.c b/kernel/events/core.c
index cfe625e..a301c68 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6741,7 +6741,12 @@ err_context:
        perf_unpin_context(ctx);
        put_ctx(ctx);
 err_alloc:
-       free_event(event);
+       /*
+        * If event_file is set, the fput() above will have called ->release()
+        * and that will take care of freeing the event.
+        */
+       if (!event_file)
+               free_event(event);
 err_task:
        if (task)
                put_task_struct(task);