Patch "virtio_blk: Fix an SG_IO regression" has been added to the 4.13-stable tree

This is a note to let you know that I've just added the patch titled

virtio_blk: Fix an SG_IO regression

to the 4.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
virtio_blk-fix-an-sg_io-regression.patch
and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Bart Van Assche <[email protected]>
Date: Fri, 27 Oct 2017 08:23:21 -0600
Subject: virtio_blk: Fix an SG_IO regression

From: Bart Van Assche <[email protected]>

commit efea2abcb03215f2efadfe994ff7f652aaff196b upstream.

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!

Moved virtblk_initialize_rq() inside CONFIG_VIRTIO_BLK_SCSI.

---
 drivers/block/virtio_blk.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

@@ -593,10 +593,22 @@ static int virtblk_map_queues(struct blk
 	return blk_mq_virtio_map_queues(set, vblk->vdev, 0);
 }
 
+#ifdef CONFIG_VIRTIO_BLK_SCSI
+static void virtblk_initialize_rq(struct request *req)
+{
+	struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
+
+	scsi_req_init(&vbr->sreq);
+}
+#endif
+
 static const struct blk_mq_ops virtio_mq_ops = {
 	.queue_rq	= virtio_queue_rq,
 	.complete	= virtblk_request_done,
 	.init_request	= virtblk_init_request,
+#ifdef CONFIG_VIRTIO_BLK_SCSI
+	.initialize_rq_fn = virtblk_initialize_rq,
+#endif
 	.map_queues	= virtblk_map_queues,
 };
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.13/virtio_blk-fix-an-sg_io-regression.patch