Commit ed8b45a3 authored Dec 10, 2015 by Joe Thornber Committed by Mike Snitzer Dec 10, 2015

dm btree: fix bufio buffer leaks in dm_btree_del() error path



If dm_btree_del()'s call to push_frame() fails, e.g. due to
btree_node_validator finding invalid metadata, the dm_btree_del() error
path must unlock all frames (which have active dm-bufio buffers) that
were pushed onto the del_stack.

Otherwise, dm_bufio_client_destroy() will BUG_ON() because dm-bufio
buffers have leaked, e.g.:
  device-mapper: bufio: leaked buffer 3, hold count 1, list 0

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

parent 50dd842a

drivers/md/persistent-data/dm-btree.c

+15 −1

Original line number	Diff line number	Diff line
		@@ -257,6 +257,16 @@ static void pop_frame(struct del_stack *s)
		dm_tm_unlock(s->tm, f->b);
		}

		static void unlock_all_frames(struct del_stack *s)
		{
		struct frame *f;

		while (unprocessed_frames(s)) {
		f = s->spine + s->top--;
		dm_tm_unlock(s->tm, f->b);
		}
		}

		int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
		{
		int r;
		@@ -313,9 +323,13 @@ int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
		pop_frame(s);
		}
		}

		out:
		if (r) {
		/* cleanup all frames of del_stack */
		unlock_all_frames(s);
		}
		kfree(s);

		return r;
		}
		EXPORT_SYMBOL_GPL(dm_btree_del);