Hi Here I'm sending backport of patch 17181fb7a0c3a279196c0eeb2caba65a1519614b. It is suitable for stable branches 3.15 to 3.18.
Mikulas commit 17181fb7a0c3a279196c0eeb2caba65a1519614b Author: Mikulas Patocka <[email protected]> Date: Wed Nov 5 17:00:13 2014 -0500 dm thin: fix a race in thin_dtr As long as struct thin_c is in the list, anyone can grab a reference of it. Consequently, we must wait for the reference count to drop to zero *after* we remove the structure from the list, not before. Signed-off-by: Mikulas Patocka <[email protected]> Signed-off-by: Mike Snitzer <[email protected]> diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 8c5504c..767417a 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -3622,14 +3622,14 @@ static void thin_dtr(struct dm_target *ti) struct thin_c *tc = ti->private; unsigned long flags; - thin_put(tc); - wait_for_completion(&tc->can_destroy); - spin_lock_irqsave(&tc->pool->lock, flags); list_del_rcu(&tc->list); spin_unlock_irqrestore(&tc->pool->lock, flags); synchronize_rcu(); + thin_put(tc); + wait_for_completion(&tc->can_destroy); + mutex_lock(&dm_thin_pool_table.mutex); __pool_dec(tc->pool); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
