[RFC PATCH 6/6] perf: Fix double put_ctx

[Frederic Weisbecker <fweisbec@gmail.com>]

If we call free_event on fail case of event creation, it
already put the context. The falldown goto, though, also
does a put_ctx, which might dereference a freed context.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Borislav Petkov <bp@amd64.org>
---
 kernel/perf_event.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index b6e854f..925b53e 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -5364,6 +5364,8 @@ SYSCALL_DEFINE5(perf_event_open,
 
 err_free_put_context:
 	free_event(event);
+	fput_light(group_file, fput_needed);
+	goto err_fd;
 err_put_context:
 	fput_light(group_file, fput_needed);
 	put_ctx(ctx);
-- 
1.6.2.3