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

kernel/trace/trace_workqueue.c

+14 −6
Original line number Diff line number Diff line
@@ -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)