Re: [PATCH] virtio-net: failover: add missing remove_migration_state_change_notifier()

[Jason Wang]

在 2021/4/27 下午9:51, Laurent Vivier 写道:
> In the failover case configuration, virtio_net_device_realize() uses an
> add_migration_state_change_notifier() to add a state notifier, but this
> notifier is not removed by the unrealize function when the virtio-net
> card is unplugged.
>
> If the card is unplugged and a migration is started, the notifier is
> called and as it is not valid anymore QEMU crashes.
>
> This patch fixes the problem by adding the
> remove_migration_state_change_notifier() in virtio_net_device_unrealize().
>
> The problem can be reproduced with:
>
>    $ qemu-system-x86_64 -enable-kvm -m 1g -M q35 \
>      -device pcie-root-port,slot=4,id=root1 \
>      -device pcie-root-port,slot=5,id=root2 \
>      -device virtio-net-pci,id=net1,mac=52:54:00:6f:55:cc,failover=on,bus=root1 
> \
>      -monitor stdio disk.qcow2
>    (qemu) device_del net1
>    (qemu) migrate "exec:gzip -c > STATEFILE.gz"
>
>    Thread 1 "qemu-system-x86" received signal SIGSEGV, Segmentation fault.
>    0x0000000000000000 in ?? ()
>    (gdb) bt
>    #0  0x0000000000000000 in  ()
>    #1  0x0000555555d726d7 in notifier_list_notify (...)
>        at .../util/notify.c:39
>    #2  0x0000555555842c1a in migrate_fd_connect (...)
>        at .../migration/migration.c:3975
>    #3  0x0000555555950f7d in migration_channel_connect (...)
>        error@entry=0x0) at .../migration/channel.c:107
>    #4  0x0000555555910922 in exec_start_outgoing_migration (...)
>        at .../migration/exec.c:42
>
> Reported-by: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>


Acked-by: Jason Wang <jasowang@redhat.com>

This should be added to stable I guess.

Thanks


> ---
>   hw/net/virtio-net.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 66b9ff451185..914051feb75b 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -3373,6 +3373,7 @@ static void virtio_net_device_unrealize(DeviceState *dev)
>   
>       if (n->failover) {
>           device_listener_unregister(&n->primary_listener);
> +        remove_migration_state_change_notifier(&n->migration_state);
>       }
>   
>       max_queues = n->multiqueue ? n->max_queues : 1;