virtio_ring: mark ring unused on error

commit 1861ba626ae9b98136f3e504208cdef6b29cd3ec upstream.

A recently added error path does not mark ring unused when exiting on
OOM, which will lead to BUG on the next entry in debug builds.

TODO: refactor code so we have START_USE and END_USE in the same function.

Fixes: fc6d70f40b3d ("virtio_ring: check desc == NULL when using indirect with packed")
Cc: "Xuan Zhuo" <xuanzhuo@linux.alibaba.com>
Cc: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index cce75d3..3cc2a4e 100644 (file)
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1124,8 +1124,10 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
        if (virtqueue_use_indirect(_vq, total_sg)) {
                err = virtqueue_add_indirect_packed(vq, sgs, total_sg, out_sgs,
                                                    in_sgs, data, gfp);
-               if (err != -ENOMEM)
+               if (err != -ENOMEM) {
+                       END_USE(vq);
                        return err;
+               }
 
                /* fall back on direct */
        }