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authorKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>2009-03-13 09:03:04 +0900
committerSteven Rostedt <srostedt@redhat.com>2009-03-12 21:23:47 -0400
commit889a6c367283709a80dad9413488472596a1a1d2 (patch)
treefabe1614e30f9d6e306376159a05e91721b6cb60 /kernel
parent39842323ceb368d2ea36ab7696aedbe296e13b61 (diff)
downloadop-kernel-dev-889a6c367283709a80dad9413488472596a1a1d2.zip
op-kernel-dev-889a6c367283709a80dad9413488472596a1a1d2.tar.gz
tracing: Don't use tracing_record_cmdline() in workqueue tracer fix
commit c3ffc7a40b7e94b094efe1c8ab4e24370a782b65 "Don't use tracing_record_cmdline() in workqueue tracer" has a race window. find_task_by_vpid() requires task_list_lock(). LKML-Reference: <20090313090042.43CD.A69D9226@jp.fujitsu.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_workqueue.c20
1 files changed, 14 insertions, 6 deletions
diff --git a/kernel/trace/trace_workqueue.c b/kernel/trace/trace_workqueue.c
index fb5ccac..9ab035b 100644
--- a/kernel/trace/trace_workqueue.c
+++ b/kernel/trace/trace_workqueue.c
@@ -193,12 +193,20 @@ static int workqueue_stat_show(struct seq_file *s, void *p)
struct cpu_workqueue_stats *cws = p;
unsigned long flags;
int cpu = cws->cpu;
- struct task_struct *tsk = find_task_by_vpid(cws->pid);
-
- seq_printf(s, "%3d %6d %6u %s\n", cws->cpu,
- atomic_read(&cws->inserted),
- cws->executed,
- tsk ? tsk->comm : "<...>");
+ struct pid *pid;
+ struct task_struct *tsk;
+
+ pid = find_get_pid(cws->pid);
+ if (pid) {
+ tsk = get_pid_task(pid, PIDTYPE_PID);
+ if (tsk) {
+ seq_printf(s, "%3d %6d %6u %s\n", cws->cpu,
+ atomic_read(&cws->inserted), cws->executed,
+ tsk->comm);
+ put_task_struct(tsk);
+ }
+ put_pid(pid);
+ }
spin_lock_irqsave(&workqueue_cpu_stat(cpu)->lock, flags);
if (&cws->list == workqueue_cpu_stat(cpu)->list.next)
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