drbd: fix a race stopping the worker thread

We may implicitly call drbd_send() from inside wait_for_work(),
via maybe_send_barrier().

If the "stop" signal was send just before that, drbd_send() would call
flush_signals(), and we would run an unbounded schedule() afterwards.

Fix: check for thread_state == RUNNING before we schedule()

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This commit is contained in:
Lars Ellenberg 2013-12-27 17:17:25 +01:00 committed by Philipp Reisner
parent c7a58db4e9
commit a80ca1ae81

View file

@ -1930,6 +1930,9 @@ static void wait_for_work(struct drbd_connection *connection, struct list_head *
if (send_barrier)
maybe_send_barrier(connection,
connection->send.current_epoch_nr + 1);
/* drbd_send() may have called flush_signals() */
if (get_t_state(&connection->worker) != RUNNING)
break;
schedule();
/* may be woken up for other things but new work, too,
* e.g. if the current epoch got closed.