linux-kernel - [tip:perf/urgent] perf: Do not double free

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Message-ID: <tip-130056275ade730e7a79c110212c8815202773ee@git.kernel.org>
Date:	Thu, 25 Feb 2016 00:04:09 -0800
From:	tip-bot for Peter Zijlstra <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	acme@...hat.com, tglx@...utronix.de,
	alexander.shishkin@...ux.intel.com, torvalds@...ux-foundation.org,
	hpa@...or.com, jolsa@...hat.com, linux-kernel@...r.kernel.org,
	peterz@...radead.org, mingo@...nel.org
Subject: [tip:perf/urgent] perf: Do not double free

Commit-ID:  130056275ade730e7a79c110212c8815202773ee
Gitweb:     http://git.kernel.org/tip/130056275ade730e7a79c110212c8815202773ee
Author:     Peter Zijlstra <peterz@...radead.org>
AuthorDate: Wed, 24 Feb 2016 18:45:41 +0100
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 25 Feb 2016 08:42:32 +0100

perf: Do not double free

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@...ux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: dvyukov@...gle.com
Cc: eranian@...gle.com
Cc: oleg@...hat.com
Cc: panand@...hat.com
Cc: sasha.levin@...cle.com
Cc: vince@...ter.net
Link: http://lkml.kernel.org/r/20160224174947.697350349@infradead.org
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 kernel/events/core.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index d7b0316..211a5ce 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8520,7 +8520,12 @@ 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_cpus:
 	put_online_cpus();
 err_task: