softlockup: convert read_lock in hung_task to rcu_read_lock
Since the tasklist is protected by rcu list operations, it is safe
to convert the read_lock()s to rcu_read_lock().
Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index 481ca8b..3951a80 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -155,7 +155,7 @@
if (test_taint(TAINT_DIE) || did_panic)
return;
- read_lock(&tasklist_lock);
+ rcu_read_lock();
do_each_thread(g, t) {
if (!--max_count)
goto unlock;
@@ -171,7 +171,7 @@
check_hung_task(t, now, timeout);
} while_each_thread(g, t);
unlock:
- read_unlock(&tasklist_lock);
+ rcu_read_unlock();
}
static void update_poll_jiffies(void)