-----Original Message-----
From: Jason Wang [mailto:address@hidden
Sent: Friday, September 14, 2018 8:45 PM
To: liujunjie (A) <address@hidden>; address@hidden
Cc: Huangweidong (C) <address@hidden>; wangxin (U)
<address@hidden>; address@hidden; Gonglei (Arei)
<address@hidden>; Zhoujian (jay) <address@hidden>
Subject: Re: [Qemu-devel] [PATCH] clean up callback when del virtqueue
On 2018年09月08日 21:04, liujunjie wrote:
Before, we did not clear callback like handle_output when delete the
virtqueue which may result be segmentfault.
The scene is as follows:
1. Start a vm with multiqueue vhost-net, 2. then we write
VIRTIO_PCI_GUEST_FEATURES in PCI configuration to triger multiqueue
disable in this vm which will delete the virtqueue.
In this step, the tx_bh is deleted but the callback
virtio_net_handle_tx_bh still exist.
3. Finally, we write VIRTIO_PCI_QUEUE_NOTIFY in PCI configuration to
notify the deleted virtqueue. In this way, virtio_net_handle_tx_bh
will be called and qemu will be crashed.
Good catch.
Although the way described above is uncommon, we had better reinforce it.
Signed-off-by: liujunjie <address@hidden>
---
hw/net/virtio-net.c | 4 +++-
hw/virtio/virtio.c | 3 +++
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index
f154756..9bb20e3 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1467,7 +1467,9 @@ static void virtio_net_handle_tx_bh(VirtIODevice
*vdev, VirtQueue *vq)
return;
}
virtio_queue_set_notification(vq, 0);
- qemu_bh_schedule(q->tx_bh);
+ if (q->tx_bh) {
+ qemu_bh_schedule(q->tx_bh);
+ }
I believe this is not necessary since handle_output is NULL now?