On Fri, Apr 13, 2018 at 12:03 PM, Josef Bacik <josef@toxicpanda.com> wrote:

> From: Josef Bacik <jbacik@fb.com>
>
> This fixes a use after free bug, we need to do the del_gendisk after we
> cleanup the queue on the device.
>

The three patches Josef submitted today fix the problem with the online
rbd-nbd expansion completely.

Fixes: c6a4759ea0c9 ("nbd: add device refcounting")

> cc: stable@vger.kernel.org

> Signed-off-by: Josef Bacik <jbacik@fb.com>
Tested-by: Alex Gorbachev <ag@iss-integration.com>

> ---

>  drivers/block/nbd.c | 2 +-

>  1 file changed, 1 insertion(+), 1 deletion(-)

>
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c

> index 86258b00a1d4..e33da3e6aa20 100644

> --- a/drivers/block/nbd.c

> +++ b/drivers/block/nbd.c

> @@ -174,8 +174,8 @@ static void nbd_dev_remove(struct nbd_device *nbd)

>  {

>         struct gendisk *disk = nbd->disk;

>         if (disk) {

> -               del_gendisk(disk);

>                 blk_cleanup_queue(disk->queue);

> +               del_gendisk(disk);

>                 blk_mq_free_tag_set(&nbd->tag_set);

>                 disk->private_data = NULL;

>                 put_disk(disk);

> --

> 2.14.3

>
>