[PATCH 3.19 087/175] blk-mq: fix double-free in error path

Greg Kroah-Hartman
2015-03-04T06:48:44Z

From: Tony Battersby <tonyb@cybernetics.com>

commit 564e559f2baf6a868768d0cac286980b3cfd6e30 upstream.

If the allocation of bt->bs fails, then bt->map can be freed twice, once
in blk_mq_init_bitmap_tags() -> bt_alloc(), and once in
blk_mq_init_bitmap_tags() -> bt_free(). Fix by setting the pointer to
NULL after the first free.

Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
block/blk-mq-tag.c | 1 +
1 file changed, 1 insertion(+)

--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -509,6 +509,7 @@ static int bt_alloc(struct blk_mq_bitmap
bt->bs = kzalloc(BT_WAIT_QUEUES * sizeof(*bt->bs), GFP_KERNEL);
if (!bt->bs) {
kfree(bt->map);
+ bt->map = NULL;
return -ENOMEM;
}