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

[Jason Wang <jasowang@redhat.com>]

在 2021/4/28 下午6:14, Michael S. Tsirkin 写道:
> On Tue, Apr 27, 2021 at 03:02:34PM +0100, Dr. David Alan Gilbert wrote:
>> * Laurent Vivier (lvivier@redhat.com) wrote:
>>> 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>
>> Yep, I think that's OK.
>>
>>
>> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
>
> net stuff so I expect Jason will merge this ...


Ok, I've queued this.

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;
>>> -- 
>>> 2.30.2
>>>
>> -- 
>> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
>