[tip:perf/core] perf record: Fix race where process can disappear while reading its /proc/pid/tasks
From: tip-bot for Arnaldo Carvalho de Melo
Date: Tue Oct 27 2009 - 09:04:22 EST
Commit-ID: 7f3bedcc93f935631d2363f23de1cc80f04fdf3e
Gitweb: http://git.kernel.org/tip/7f3bedcc93f935631d2363f23de1cc80f04fdf3e
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Mon, 26 Oct 2009 19:23:17 -0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Tue, 27 Oct 2009 13:51:53 +0100
perf record: Fix race where process can disappear while reading its /proc/pid/tasks
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
LKML-Reference: <1256592199-9608-1-git-send-email-acme@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
tools/perf/builtin-record.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index ac5ddff..9e1638c 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -206,6 +206,7 @@ static pid_t pid_synthesize_comm_event(pid_t pid, int full)
fp = fopen(filename, "r");
if (fp == NULL) {
+out_race:
/*
* We raced with a task exiting - just return:
*/
@@ -247,6 +248,9 @@ static pid_t pid_synthesize_comm_event(pid_t pid, int full)
snprintf(filename, sizeof(filename), "/proc/%d/task", pid);
tasks = opendir(filename);
+ if (tasks == NULL)
+ goto out_race;
+
while (!readdir_r(tasks, &dirent, &next) && next) {
char *end;
pid = strtol(dirent.d_name, &end, 10);
--
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