4.4-stable review patch. If anyone has any objections, please let me know.
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From: Halil Pasic pasic@linux.ibm.com
commit 3438b2c039b4bf26881786a1f3450f016d66ad11 upstream.
A queue with a capacity of zero is clearly not a valid virtio queue. Some emulators report zero queue size if queried with an invalid queue index. Instead of crashing in this case let us just return -ENOENT. To make that work properly, let us fix the notifier cleanup logic as well.
Cc: stable@vger.kernel.org Signed-off-by: Halil Pasic pasic@linux.ibm.com Signed-off-by: Cornelia Huck cohuck@redhat.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/s390/virtio/virtio_ccw.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/s390/virtio/virtio_ccw.c +++ b/drivers/s390/virtio/virtio_ccw.c @@ -283,6 +283,8 @@ static void virtio_ccw_drop_indicators(s { struct virtio_ccw_vq_info *info;
+ if (!vcdev->airq_info) + return; list_for_each_entry(info, &vcdev->virtqueues, node) drop_airq_indicator(info->vq, vcdev->airq_info); } @@ -423,7 +425,7 @@ static int virtio_ccw_read_vq_conf(struc ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_VQ_CONF); if (ret) return ret; - return vcdev->config_block->num; + return vcdev->config_block->num ?: -ENOENT; }
static void virtio_ccw_del_vq(struct virtqueue *vq, struct ccw1 *ccw)