Re: [bug report] regression bisected to "block: Make most scsi_req_init() calls implicit"

[Bart Van Assche]

On Mon, 2017-10-23 at 09:41 -0600, dann frazier wrote:
> (gdb) list *(sg_io+0x120)
> 0xffff0000084e71a8 is in sg_io (./include/linux/uaccess.h:113).
> 108   static inline unsigned long
> 109   _copy_from_user(void *to, const void __user *from, unsigned long n)
> 110   {
> 111           unsigned long res = n;
> 112           might_fault();
> 113           if (likely(access_ok(VERIFY_READ, from, n))) {
> 114                   kasan_check_write(to, n);
> 115                   res = raw_copy_from_user(to, from, n);
> 116           }
> 117           if (unlikely(res))

Hello Dann,

Would it be possible to check whether the patch below is sufficient to fix this?

Thanks,

Bart.


diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 34e17ee799be..15e11a519801 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -597,6 +597,7 @@ static const struct blk_mq_ops virtio_mq_ops = {
        .queue_rq       = virtio_queue_rq,
        .complete       = virtblk_request_done,
        .init_request   = virtblk_init_request,
+       .initialize_rq_fn = scsi_initialize_rq,
        .map_queues     = virtblk_map_queues,
 };
 
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 0419c2298eab..14096f67eebb 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1722,6 +1722,8 @@ sg_start_req(Sg_request *srp, unsigned char *cmd)
        }
        req = scsi_req(rq);
 
+       WARN_ON_ONCE(!req->cmd);
+
        if (hp->cmd_len > BLK_MAX_CDB)
                req->cmd = long_cmdp;
        memcpy(req->cmd, cmd, hp->cmd_len);