[PATCH 3.2 113/126] perf: Do not double free

From: Ben Hutchings
Date: Wed Feb 15 2017 - 18:22:40 EST

3.2.85-rc1 review patch. If anyone has any objections, please let me know.


From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: dvyukov@xxxxxxxxxx
Cc: eranian@xxxxxxxxxx
Cc: oleg@xxxxxxxxxx
Cc: panand@xxxxxxxxxx
Cc: sasha.levin@xxxxxxxxxx
Cc: vince@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20160224174947.697350349@xxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
kernel/events/core.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6741,7 +6741,12 @@ err_context:
- 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);
if (task)