From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Kacur Subject: [PATCH 3/6] perf: Fix errors path in perf_output_begin() Date: Tue, 15 Jun 2010 00:21:24 +0200 Message-ID: <1276554087-3632-4-git-send-email-jkacur@redhat.com> References: <1276554087-3632-1-git-send-email-jkacur@redhat.com> Cc: lkml , rt-users , Clark Williams , Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar To: Thomas Gleixner Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:55901 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757037Ab0FNWVf (ORCPT ); Mon, 14 Jun 2010 18:21:35 -0400 In-Reply-To: <1276554087-3632-1-git-send-email-jkacur@redhat.com> Sender: linux-rt-users-owner@vger.kernel.org List-ID: From: Stephane Eranian 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. Signed-off-by: Stephane Eranian Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker LKML-Reference: <4bf13674.014fd80a.6c82.ffffb20c@mx.google.com> Signed-off-by: Ingo Molnar Upstream-commit: 00d1d0b095ba4e5c0958cb228b2a9c445d4a339d Signed-off-by: John Kacur --- 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 43c1dfb..e353be2 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -2933,7 +2933,7 @@ 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) -- 1.6.6.1