[Qemu-devel] [PATCH] virtio-net: fix wild pointer when remove virtio-net queues

[Yunjian Wang]

The tx_bh or tx_timer will free in virtio_net_del_queue() function, when
removing virtio-net queues if the guest doesn't support multiqueue. But
it might be still referenced by virtio_net_set_status(), which needs to
be set NULL. And also the tx_waiting needs to be set zero to prevent
virtio_net_set_status() accessing tx_bh or tx_timer.

Signed-off-by: Yunjian Wang <address@hidden>
---
 hw/net/virtio-net.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 7d091c9..98bd683 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1522,9 +1522,12 @@ static void virtio_net_del_queue(VirtIONet *n, int index)
     if (q->tx_timer) {
         timer_del(q->tx_timer);
         timer_free(q->tx_timer);
+        q->tx_timer = NULL;
     } else {
         qemu_bh_delete(q->tx_bh);
+        q->tx_bh = NULL;
     }
+    q->tx_waiting = 0;
     virtio_del_queue(vdev, index * 2 + 1);
 }
 
-- 
1.8.3.1