Commit 889a6c36 authored by KOSAKI Motohiro's avatar KOSAKI Motohiro Committed by Steven Rostedt

tracing: Don't use tracing_record_cmdline() in workqueue tracer fix

commit c3ffc7a4
"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: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
parent 39842323
......@@ -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);
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 ? tsk->comm : "<...>");
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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