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Re: [PATCH] migration: handle CANCELLING state in migration_completion()
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [PATCH] migration: handle CANCELLING state in migration_completion() |
Date: |
Thu, 12 Nov 2020 15:30:58 +0000 |
User-agent: |
Mutt/1.14.6 (2020-07-11) |
* Longpeng(Mike) (longpeng2@huawei.com) wrote:
> The following sequence may cause the VM abort during migration:
>
> 1. RUN_STATE_RUNNING,MIGRATION_STATUS_ACTIVE
>
> 2. before call migration_completion(), we send migrate_cancel
> QMP command, the state machine is changed to:
> RUN_STATE_RUNNING,MIGRATION_STATUS_CANCELLING
>
> 3. call migration_completion(), and the state machine is
> switch to: RUN_STATE_RUNNING,MIGRATION_STATUS_COMPLETED
>
> 4. call migration_iteration_finish(), because the migration
> status is COMPLETED, so it will try to set the runstate
> to POSTMIGRATE, but RUNNING-->POSTMIGRATE is an invalid
> transition, so abort().
>
> The migration_completion() should not change the migration state
> to COMPLETED if it is already changed to CANCELLING.
>
> Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Queued
> ---
> migration/migration.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index 3263aa5..b11a2bd 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -3061,6 +3061,8 @@ static void migration_completion(MigrationState *s)
>
> qemu_savevm_state_complete_postcopy(s->to_dst_file);
> trace_migration_completion_postcopy_end_after_complete();
> + } else if (s->state == MIGRATION_STATUS_CANCELLING) {
> + goto fail;
> }
>
> /*
> --
> 1.8.3.1
>
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK