| From 873f3ba5d222ac2b0aa60ef0dc647fc9d9c0e7a3 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> |
| |
| diff --git a/kernel/perf_event.c b/kernel/perf_event.c |
| index ee1d0ab..395369a 100644 |
| --- a/kernel/perf_event.c |
| +++ b/kernel/perf_event.c |
| @@ -2881,7 +2881,7 @@ 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) |
| -- |
| 1.7.1.1 |
| |
