2021-06-02 11:55:10

by Colin King

Subject: [PATCH][next] null_blk: Fix null pointer dereference on nullb->disk on blk_cleanup_disk call

From: Colin Ian King <[email protected]>

The error handling on a nullb->disk allocation currently jumps to
out_cleanup_disk that calls blk_cleanup_disk with a null pointer causing
a null pointer dereference issue. Fix this by jumping to out_cleanup_tags
instead.

Addresses-Coverity: ("Dereference after null check")
Fixes: 132226b301b5 ("null_blk: convert to blk_alloc_disk/blk_cleanup_disk")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/block/null_blk/main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index d8e098f1e5b5..83d803cb57c8 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -1856,7 +1856,7 @@ static int null_add_dev(struct nullb_device *dev)
goto out_cleanup_tags;
nullb->disk = alloc_disk_node(1, nullb->dev->home_node);
if (!nullb->disk)
- goto out_cleanup_disk;
+ goto out_cleanup_tags;
nullb->disk->queue = nullb->q;
} else if (dev->queue_mode == NULL_Q_BIO) {
rv = -ENOMEM;
--
2.31.1

2021-06-03 00:04:47

by Chaitanya Kulkarni

Subject: Re: [PATCH][next] null_blk: Fix null pointer dereference on nullb->disk on blk_cleanup_disk call

On 6/2/21 03:07, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> The error handling on a nullb->disk allocation currently jumps to
> out_cleanup_disk that calls blk_cleanup_disk with a null pointer causing
> a null pointer dereference issue. Fix this by jumping to out_cleanup_tags
> instead.
>
> Addresses-Coverity: ("Dereference after null check")
> Fixes: 132226b301b5 ("null_blk: convert to blk_alloc_disk/blk_cleanup_disk")
> Signed-off-by: Colin Ian King <[email protected]>

Looks good.

Reviewed-by: Chaitanya Kulkarni <[email protected]>

2021-06-03 05:50:40

by Christoph Hellwig

Subject: Re: [PATCH][next] null_blk: Fix null pointer dereference on nullb->disk on blk_cleanup_disk call

Looks good,

Reviewed-by: Christoph Hellwig <[email protected]>

2021-06-03 15:58:28

by Jens Axboe

Subject: Re: [PATCH][next] null_blk: Fix null pointer dereference on nullb->disk on blk_cleanup_disk call

On 6/2/21 4:06 AM, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> The error handling on a nullb->disk allocation currently jumps to
> out_cleanup_disk that calls blk_cleanup_disk with a null pointer causing
> a null pointer dereference issue. Fix this by jumping to out_cleanup_tags
> instead.

Applied, thanks.

--
Jens Axboe