Re: [PATCH] tests/migration: Print some debug on bad status

[Jens Freimann <jfreimann@redhat.com>]

On Fri, Nov 08, 2019 at 06:38:17PM +0000, Dr. David Alan Gilbert wrote:
>Hi Jens,
>  the unplug failover stuff is triggering an assertion occasionally on
>aarch64; but
>  a) I'm not sure the right way to fix it
>  b) And I'm out for a little over a week
>
>so...

I'll take care of it. 

>
>* no-reply@patchew.org (no-reply@patchew.org) wrote:
>> Patchew URL: https://patchew.org/QEMU/20191108104307.125020-1-dgilbert@redhat.com/
>>
>>
>>
>> Hi,
>>
>> This series failed the docker-quick@centos7 build test. Please find the testing commands and
>> their output below. If you have Docker installed, you can probably reproduce it
>> locally.
>>
>> === TEST SCRIPT BEGIN ===
>> #!/bin/bash
>> make docker-image-centos7 V=1 NETWORK=1
>> time make docker-test-quick@centos7 SHOW_ENV=1 J=14 NETWORK=1
>> === TEST SCRIPT END ===
>>
>>   TEST    check-unit: tests/test-bdrv-drain
>> wait_for_migration_fail: unexpected status status=wait-unplug allow_active=1
>
>In tests/migration-test.c we've got wait_for_migration_fail, and it's
>expecting the state to be any one of:
>   setup, failed or maybe active
>
>but it's getting surprised by seeing a 'wait-unplug'
>
>So the question is should we see a wait-unplug?
>
>the migration code has:
>
>    if (qemu_savevm_nr_failover_devices()) {
>        migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
>                          MIGRATION_STATUS_WAIT_UNPLUG);
>
>Should qemu_savevm_nr_failover_devices() be true?
>On aarch64 it seems to have a virtio-net device by default
>and qemu_savevm_nr_failover_devices() checks for devices
>having dev_unplug_pending but doesn't call it.
>
>I see two fixes but am not sure which is right:
>   a) Add 'wait-unplug' to the wait_for_migration_fail
>      (easy)
>   b) Actually call dev_unplug_pending in qemu_savevm_nr_failover_devices
>      so that on a guest which has a virtio-net, but no failover device,
>      the state isn't entered.

I also prefer b over a, but I should only set up dev_unplug_pending when
failover=on to avoid this. I'll send a patch.

regards
Jens