From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752534AbaFBSC1 (ORCPT ); Mon, 2 Jun 2014 14:02:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50470 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750767AbaFBSC0 (ORCPT ); Mon, 2 Jun 2014 14:02:26 -0400 From: Jiri Olsa To: linux-kernel@vger.kernel.org Cc: Jiri Olsa , Arnaldo Carvalho de Melo , Corey Ashford , David Ahern , Frederic Weisbecker , Ingo Molnar , Namhyung Kim , Paul Mackerras , Peter Zijlstra Subject: [PATCH] perf record: Fix poll return value propagation Date: Mon, 2 Jun 2014 20:02:06 +0200 Message-Id: <1401732126-19465-1-git-send-email-jolsa@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If the perf record command is interrupted in record__mmap_read_all function, the 'done' is set and err has the latest poll return value, which is most likely positive number (= number of pollfds ready to read). This 'positive err' is then propagated to the exit code, resulting in not finishing the perf.data header properly, causing following error in report: # perf record -F 50000 -a --- make the system real busy, so there's more chance to interrupt perf in event writing code --- ^C[ perf record: Woken up 16 times to write data ] [ perf record: Captured and wrote 30.292 MB perf.data (~1323468 samples) ] # perf report --stdio > /dev/null WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? Fixing this by checking for positive poll return value and setting err to 0. Cc: Arnaldo Carvalho de Melo Cc: Corey Ashford Cc: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Signed-off-by: Jiri Olsa --- tools/perf/builtin-record.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index e4c85b8..ce2cfec 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -454,7 +454,11 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) if (done) break; err = poll(rec->evlist->pollfd, rec->evlist->nr_fds, -1); - if (err < 0 && errno == EINTR) + /* + * Propagate error, only if there's any. Ignore positive + * number of returned events and interrupt error. + */ + if (err > 0 || (err < 0 && errno == EINTR)) err = 0; waking++; } -- 1.8.3.1