Commit 8d24790e authored by Benjamin Marzinski's avatar Benjamin Marzinski Committed by Mike Snitzer
Browse files

dm-delay: fix workqueue delay_timer race 



delay_timer could be pending when delay_dtr() is called. It needs to be
shut down before kdelayd_wq is destroyed, so it won't try queueing more
work to kdelayd_wq while that's getting destroyed.

Also the del_timer_sync() call in delay_presuspend() doesn't protect
against the timer getting immediately rearmed by the queued call to
flush_delayed_bios(), but there's no real harm if that does happen.
timer_delete() is less work, and is basically just as likely to stop a
pointless call to flush_delayed_bios().

Fixes: 26b9f228 ("dm: delay target")
Signed-off-by: default avatarBenjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
parent 83637d90

drivers/md/dm-delay.c

+4 −2
Original line number Diff line number Diff line
@@ -154,8 +154,10 @@ static void delay_dtr(struct dm_target *ti) 
{

	struct delay_c *dc = ti->private;



	if (dc->kdelayd_wq)

	if (dc->kdelayd_wq) {

		timer_shutdown_sync(&dc->delay_timer);

		destroy_workqueue(dc->kdelayd_wq);

	}



	if (dc->read.dev)

		dm_put_device(ti, dc->read.dev);
@@ -335,7 +337,7 @@ static void delay_presuspend(struct dm_target *ti) 
	mutex_unlock(&delayed_bios_lock);



	if (!delay_is_fast(dc))

		del_timer_sync(&dc->delay_timer);

		timer_delete(&dc->delay_timer);

	flush_delayed_bios(dc, true);

}