Linux Kernels

s390/virtio: handle find on invalid queue gracefully

This change “s390/virtio: handle find on invalid queue gracefully” (commit 3438b2c) in Linux kernel is authored by Halil Pasic <pasic [at] linux.ibm.com> on Mon Jan 21 13:19:43 2019 +0100.

Description of "s390/virtio: handle find on invalid queue gracefully"

The change “s390/virtio: handle find on invalid queue gracefully” introduces changes as follows.

s390/virtio: handle find on invalid queue gracefully

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>

Linux kernel releases containing commit 3438b2c

Linux kernel code changes in "s390/virtio: handle find on invalid queue gracefully"

There are 4 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/s390/virtio/virtio_ccw.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
 
diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index ae1d56da671d..1a738fe9f26b 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -272,6 +272,8 @@ static void virtio_ccw_drop_indicators(struct virtio_ccw_device *vcdev)
 {
 	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);
 }
@@ -413,7 +415,7 @@ static int virtio_ccw_read_vq_conf(struct virtio_ccw_device *vcdev,
 	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)

The commit for this change in Linux stable tree is 3438b2c (patch).

Last modified: 2020/01/11 09:38