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Message-ID: <tip-613d8602292165f86ba1969784fea01a06d55900@git.kernel.org>
Date: Mon, 15 Jun 2009 08:33:43 GMT
From: tip-bot for Ingo Molnar <mingo@...e.hu>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, acme@...hat.com, paulus@...ba.org,
hpa@...or.com, mingo@...hat.com, a.p.zijlstra@...llo.nl,
efault@....de, tglx@...utronix.de, mingo@...e.hu
Subject: [tip:perfcounters/core] perf record: Fix fast task-exit race
Commit-ID: 613d8602292165f86ba1969784fea01a06d55900
Gitweb: http://git.kernel.org/tip/613d8602292165f86ba1969784fea01a06d55900
Author: Ingo Molnar <mingo@...e.hu>
AuthorDate: Mon, 15 Jun 2009 08:17:12 +0200
Committer: Ingo Molnar <mingo@...e.hu>
CommitDate: Mon, 15 Jun 2009 09:08:31 +0200
perf record: Fix fast task-exit race
Recording with -a (or with -p) can race with tasks going away:
couldn't open /proc/8440/maps
Causing an early exit() and no recording done.
Do not abort the recording session - instead just skip that task.
Also, only print the warnings under -v.
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Mike Galbraith <efault@....de>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
tools/perf/builtin-record.c | 16 ++++++++++++----
1 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index a177a59..e1dfef2 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -202,8 +202,12 @@ static void pid_synthesize_comm_event(pid_t pid, int full)
fd = open(filename, O_RDONLY);
if (fd < 0) {
- fprintf(stderr, "couldn't open %s\n", filename);
- exit(EXIT_FAILURE);
+ /*
+ * We raced with a task exiting - just return:
+ */
+ if (verbose)
+ fprintf(stderr, "couldn't open %s\n", filename);
+ return;
}
if (read(fd, bf, sizeof(bf)) < 0) {
fprintf(stderr, "couldn't read %s\n", filename);
@@ -273,8 +277,12 @@ static void pid_synthesize_mmap_samples(pid_t pid)
fp = fopen(filename, "r");
if (fp == NULL) {
- fprintf(stderr, "couldn't open %s\n", filename);
- exit(EXIT_FAILURE);
+ /*
+ * We raced with a task exiting - just return:
+ */
+ if (verbose)
+ fprintf(stderr, "couldn't open %s\n", filename);
+ return;
}
while (1) {
char bf[BUFSIZ], *pbf = bf;
--
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