On Thu, Oct 26, 2017 at 12:10:15PM +0200, Bart Van Assche wrote:
> Avoid that submitting an SG_IO ioctl triggers a kernel oops that
> is preceded by:
>
> usercopy: kernel memory overwrite attempt detected to (null) (<null>) (6 bytes)
> kernel BUG at mm/usercopy.c:72!
>
> Reported-by: Dann Frazier <dann.frazier@xxxxxxxxxxxxx>
> Fixes: commit ca18d6f769d2 ("block: Make most scsi_req_init() calls implicit")
> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx>
> Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Cc: Dann Frazier <dann.frazier@xxxxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.13
> ---
> drivers/block/virtio_blk.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index 34e17ee799be..e477d4a5181e 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -593,10 +593,20 @@ static int virtblk_map_queues(struct blk_mq_tag_set *set)
> return blk_mq_virtio_map_queues(set, vblk->vdev, 0);
> }
>
> +static void virtblk_initialize_rq(struct request *req)
> +{
> + struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
> +
> +#ifdef CONFIG_VIRTIO_BLK_SCSI
> + scsi_req_init(&vbr->sreq);
> +#endif
How about only defininig the initialize_rq method and implementation
if CONFIG_VIRTIO_BLK_SCSI is set?
Else looks good:
Reviewed-by: Christoph Hellwig <hch@xxxxxx>