Commit 9153df74 authored Aug 31, 2015 by Joe Thornber Committed by Mike Snitzer Aug 31, 2015

dm cache: fix leaking of deferred bio prison cells



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.

Fixes: 651f5fa2 ("dm cache: defer whole cells")
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.1+

parent f15f4d72

drivers/md/dm-cache-target.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -1730,6 +1730,8 @@ static void remap_cell_to_origin_clear_discard(struct cache *cache,
		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,
		@@ -1764,6 +1766,8 @@ static void remap_cell_to_cache_dirty(struct cache *cache, struct dm_bio_prison_
		remap_to_cache(cache, bio, cblock);
		issue(cache, bio);
		}

		free_prison_cell(cache, cell);
		}

		/----------------------------------------------------------------/