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From 46755bddc8fe2cf220f105b06f347b116819af3f Mon Sep 17 00:00:00 2001
From: Stephane Eranian <eranian@google.com>
Date: Mon, 17 May 2010 12:46:01 +0200
Subject: [PATCH] perf: Fix errors path in perf_output_begin()
commit ea2d2a0d32a1f98d5c1be461b715009ca7774156 in tip.
In case the sampling buffer has no "payload" pages,
nr_pages is 0. The problem is that the error path in
perf_output_begin() skips to a label which assumes
perf_output_lock() has been issued which is not the
case. That triggers a WARN_ON() in
perf_output_unlock().
This patch fixes the problem by skipping
perf_output_unlock() in case data->nr_pages is 0.
[ upstream commit: 00d1d0b095ba4e5c0958cb228b2a9c445d4a339d ]
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4bf13674.014fd80a.6c82.ffffb20c@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
kernel/perf_event.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index dd73870..0bb58a7 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -3014,7 +3014,7 @@ int perf_output_begin(struct perf_output_handle *handle,
handle->sample = sample;
if (!data->nr_pages)
- goto fail;
+ goto out;
have_lost = atomic_read(&data->lost);
if (have_lost)
--
1.7.0.4
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