cherry-pick "virtio-pci: Check if is_avq is NULL"

It's in master-next of current ubuntu noble kernel git tree and a null
check cannot really hurt.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

diff --git a/patches/kernel/0017-virtio-pci-Check-if-is_avq-is-NULL.patch b/patches/kernel/0017-virtio-pci-Check-if-is_avq-is-NULL.patch
new file mode 100644 (file)
index 0000000..a886e4c
--- /dev/null
+++ b/patches/kernel/0017-virtio-pci-Check-if-is_avq-is-NULL.patch
@@ -0,0 +1,48 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Li Zhang <zhanglikernel@gmail.com>
+Date: Tue, 18 Jun 2024 07:28:00 +0200
+Subject: [PATCH] virtio-pci: Check if is_avq is NULL
+
+BugLink: https://bugs.launchpad.net/bugs/2067862
+
+[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>
+
+(cherry picked from commit c8fae27d141a32a1624d0d0d5419d94252824498)
+Signed-off-by: Matthew Ruffell <matthew.ruffell@canonical.com>
+Acked-by: Paolo Pisati <paolo.pisati@canonical.com>
+Acked-by: Manuel Diewald <manuel.diewald@canonical.com>
+Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
+---
+ drivers/virtio/virtio_pci_common.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
+index b655fccaf773..3c18fc14cd66 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) {