[PATCH][SRU Artful] virtio_blk: Fix an SG_IO regression

dann frazier dann.frazier at canonical.com
Thu Nov 2 17:29:06 UTC 2017


From: Bart Van Assche <bart.vanassche at wdc.com>

BugLink: https://bugs.launchpad.net/bugs/1720229

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 at canonical.com>
Fixes: commit ca18d6f769d2 ("block: Make most scsi_req_init() calls implicit")
Signed-off-by: Bart Van Assche <bart.vanassche at wdc.com>
Cc: Michael S. Tsirkin <mst at redhat.com>
Cc: Dann Frazier <dann.frazier at canonical.com>
Cc: <stable at vger.kernel.org> # v4.13
Reviewed-by: Christoph Hellwig <hch at lst.de>

Moved virtblk_initialize_rq() inside CONFIG_VIRTIO_BLK_SCSI.

Signed-off-by: Jens Axboe <axboe at kernel.dk>
(cherry picked from commit efea2abcb03215f2efadfe994ff7f652aaff196b)
Signed-off-by: dann frazier <dann.frazier at canonical.com>
---
 drivers/block/virtio_blk.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index d3d5523862c2..b49952b5a189 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -593,10 +593,22 @@ static int virtblk_map_queues(struct blk_mq_tag_set *set)
 	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,
 };
 
-- 
2.15.0.rc2





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