Patch "dm cache: fix leaking of deferred bio prison cells" has been added to the 4.2-stable tree

This is a note to let you know that I've just added the patch titled

dm cache: fix leaking of deferred bio prison cells

to the 4.2-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-cache-fix-leaking-of-deferred-bio-prison-cells.patch
and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Joe Thornber <[email protected]>
Date: Mon, 31 Aug 2015 18:20:08 +0100
Subject: dm cache: fix leaking of deferred bio prison cells

From: Joe Thornber <[email protected]>

commit 9153df7405ae04c1b0466de720e0a685cfea1a3a upstream.

There were two cases where dm_cell_visit_release() was being called, which removes the cell from the prison's rbtree, but the callers didn't also return the cell to the mempool. Fix this by having them call free_prison_cell().

This leak manifested as the 'kmalloc-96' slab growing until OOM.

---
 drivers/md/dm-cache-target.c |    4 ++++
 1 file changed, 4 insertions(+)

@@ -1729,6 +1729,8 @@ static void remap_cell_to_origin_clear_d
 		remap_to_origin(cache, bio);
 		issue(cache, bio);
 	}
+
+	free_prison_cell(cache, cell);
 }
 
 static void remap_cell_to_cache_dirty(struct cache *cache, struct dm_bio_prison_cell *cell,

@@ -1763,6 +1765,8 @@ static void remap_cell_to_cache_dirty(st
 		remap_to_cache(cache, bio, cblock);
 		issue(cache, bio);
 	}
+
+	free_prison_cell(cache, cell);
 }
 
 /*----------------------------------------------------------------*/

Patches currently in stable-queue which might be from [email protected] are

queue-4.2/dm-cache-fix-leaking-of-deferred-bio-prison-cells.patch