* [PATCH] migration: handle CANCELLING state in migration_completion()
@ 2020-11-05 9:17 Longpeng(Mike)
2020-11-12 10:38 ` Dr. David Alan Gilbert
2020-11-12 15:30 ` Dr. David Alan Gilbert
0 siblings, 2 replies; 3+ messages in thread
From: Longpeng(Mike) @ 2020-11-05 9:17 UTC (permalink / raw)
To: quintela, dgilbert; +Cc: longpeng2, arei.gonglei, huangzhichao, qemu-devel
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>
---
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
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] migration: handle CANCELLING state in migration_completion()
2020-11-05 9:17 [PATCH] migration: handle CANCELLING state in migration_completion() Longpeng(Mike)
@ 2020-11-12 10:38 ` Dr. David Alan Gilbert
2020-11-12 15:30 ` Dr. David Alan Gilbert
1 sibling, 0 replies; 3+ messages in thread
From: Dr. David Alan Gilbert @ 2020-11-12 10:38 UTC (permalink / raw)
To: Longpeng(Mike); +Cc: arei.gonglei, huangzhichao, qemu-devel, quintela
* 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>
Yes I think so; the only downside I see is I think this ends up going
from CACELLNG->FAILED.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
> 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
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] migration: handle CANCELLING state in migration_completion()
2020-11-05 9:17 [PATCH] migration: handle CANCELLING state in migration_completion() Longpeng(Mike)
2020-11-12 10:38 ` Dr. David Alan Gilbert
@ 2020-11-12 15:30 ` Dr. David Alan Gilbert
1 sibling, 0 replies; 3+ messages in thread
From: Dr. David Alan Gilbert @ 2020-11-12 15:30 UTC (permalink / raw)
To: Longpeng(Mike); +Cc: arei.gonglei, huangzhichao, qemu-devel, quintela
* 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
^ permalink raw reply [flat|nested] 3+ messages in thread
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