From: Li Zhang <zhanglikernel@gmail.com>
Date: Sat, 16 Mar 2024 05:25:54 +0000 (+0800)
Subject: virtio-pci: Check if is_avq is NULL
X-Git-Tag: v6.10-rc1~39^2
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=c8fae27d141a32a1624d0d0d5419d94252824498;p=linux-2.6-block.git

virtio-pci: Check if is_avq is NULL

[bug]
In the virtio_pci_common.c function vp_del_vqs, vp_dev->is_avq is involved
to determine whether it is admin virtqueue, but this function vp_dev->is_avq
 may be empty. For installations, virtio_pci_legacy does not assign a value
 to vp_dev->is_avq.

[fix]
Check whether it is vp_dev->is_avq before use.

[test]
Test with virsh Attach device
Before this patch, the following command would crash the guest system

After applying the patch, everything seems to be working fine.

Signed-off-by: Li Zhang <zhanglikernel@gmail.com>
Message-Id: <1710566754-3532-1-git-send-email-zhanglikernel@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index 584af7816532..f6b0b00e4599 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -236,7 +236,7 @@ void vp_del_vqs(struct virtio_device *vdev)
 	int i;
 
 	list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
-		if (vp_dev->is_avq(vdev, vq->index))
+		if (vp_dev->is_avq && vp_dev->is_avq(vdev, vq->index))
 			continue;
 
 		if (vp_dev->per_vq_vectors) {