On 10/27/2017 12:39 AM, Christoph Hellwig wrote:
> 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>
I did that while merging it.
--
Jens Axboe