This is a note to let you know that I've just added the patch titled
dm thin: fix race condition when destroying thin pool workqueue
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-thin-fix-race-condition-when-destroying-thin-pool-workqueue.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 18d03e8c25f173f4107a40d0b8c24defb6ed69f3 Mon Sep 17 00:00:00 2001
From: Nikolay Borisov <kernel@xxxxxxxx>
Date: Thu, 17 Dec 2015 18:03:35 +0200
Subject: dm thin: fix race condition when destroying thin pool workqueue
From: Nikolay Borisov <kernel@xxxxxxxx>
commit 18d03e8c25f173f4107a40d0b8c24defb6ed69f3 upstream.
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: 905e51b39a555 ("dm thin: commit outstanding data every second")
Fixes: 85ad643b7e7e5 ("dm thin: add timeout to stop out-of-data-space mode holding IO forever")
Signed-off-by: Nikolay Borisov <kernel@xxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/dm-thin.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -3453,8 +3453,8 @@ static void pool_postsuspend(struct dm_t
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);
}
Patches currently in stable-queue which might be from kernel@xxxxxxxx are
queue-4.4/ext4-fix-bh-b_state-corruption.patch
queue-4.4/dm-thin-fix-race-condition-when-destroying-thin-pool-workqueue.patch
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