* [PATCH] blk-mq: fix double-free in error path
@ 2015-02-11 16:32 Tony Battersby
2015-02-11 16:43 ` Jens Axboe
0 siblings, 1 reply; 2+ messages in thread
From: Tony Battersby @ 2015-02-11 16:32 UTC (permalink / raw)
To: linux-scsi, James E.J. Bottomley, Christoph Hellwig, Jens Axboe
Cc: linux-kernel
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.
Cc: <stable@vger.kernel.org>
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
---
For inclusion in kernel 3.20.
--- linux-3.19.0/block/blk-mq-tag.c.orig 2015-02-08 21:54:22.000000000 -0500
+++ linux-3.19.0/block/blk-mq-tag.c 2015-02-10 09:42:38.000000000 -0500
@@ -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;
}
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] blk-mq: fix double-free in error path
2015-02-11 16:32 [PATCH] blk-mq: fix double-free in error path Tony Battersby
@ 2015-02-11 16:43 ` Jens Axboe
0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2015-02-11 16:43 UTC (permalink / raw)
To: Tony Battersby, linux-scsi, James E.J. Bottomley,
Christoph Hellwig
Cc: linux-kernel
On 02/11/2015 09:32 AM, Tony Battersby wrote:
> 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.
>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
> ---
>
> For inclusion in kernel 3.20.
>
> --- linux-3.19.0/block/blk-mq-tag.c.orig 2015-02-08 21:54:22.000000000 -0500
> +++ linux-3.19.0/block/blk-mq-tag.c 2015-02-10 09:42:38.000000000 -0500
> @@ -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;
> }
Thanks Tony, applied.
--
Jens Axboe
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