Commit 18d03e8c authored Dec 17, 2015 by Nikolay Borisov Committed by Mike Snitzer Dec 17, 2015

dm thin: fix race condition when destroying thin pool workqueue



When a thin pool is being destroyed delayed work items are
cancelled using cancel_delayed_work(), which doesn't guarantee that on
return the delayed item isn't running.  This can cause the work item to
requeue itself on an already destroyed workqueue.  Fix this by using
cancel_delayed_work_sync() which guarantees that on return the work item
is not running anymore.

Fixes: 905e51b3 ("dm thin: commit outstanding data every second")
Fixes: 85ad643b ("dm thin: add timeout to stop out-of-data-space mode holding IO forever")
Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

parent 51216778

drivers/md/dm-thin.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -3453,8 +3453,8 @@ static void pool_postsuspend(struct dm_target *ti)
		struct pool_c *pt = ti->private;
		struct pool *pool = pt->pool;

		cancel_delayed_work(&pool->waker);
		cancel_delayed_work(&pool->no_space_timeout);
		cancel_delayed_work_sync(&pool->waker);
		cancel_delayed_work_sync(&pool->no_space_timeout);
		flush_workqueue(pool->wq);
		(void) commit(pool);
		}

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