[Qemu-devel] [RFC PATCH] vl: fix migration when watchdog expires

[Jay Zhou]

I got the following error when migrating a VM with watchdog
device:

{"timestamp": {"seconds": 1533884471, "microseconds": 668099},
"event": "WATCHDOG", "data": {"action": "reset"}}
{"timestamp": {"seconds": 1533884471, "microseconds": 677658},
"event": "RESET", "data": {"guest": true}}
{"timestamp": {"seconds": 1533884471, "microseconds": 677874},
"event": "STOP"}
qemu-system-x86_64: invalid runstate transition: 'prelaunch' -> 'postmigrate'
Aborted

The run state transition is RUN_STATE_FINISH_MIGRATE to RUN_STATE_PRELAUNCH,
then the migration thread aborted when it tries to set RUN_STATE_POSTMIGRATE.
There is a race between the main loop thread and the migration thread I think.

Signed-off-by: Jay Zhou <address@hidden>
---
 vl.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/vl.c b/vl.c
index 16b913f..298ce91 100644
--- a/vl.c
+++ b/vl.c
@@ -637,6 +637,7 @@ static const RunStateTransition runstate_transitions_def[] 
= {
     { RUN_STATE_PRELAUNCH, RUN_STATE_RUNNING },
     { RUN_STATE_PRELAUNCH, RUN_STATE_FINISH_MIGRATE },
     { RUN_STATE_PRELAUNCH, RUN_STATE_INMIGRATE },
+    { RUN_STATE_PRELAUNCH, RUN_STATE_POSTMIGRATE },
 
     { RUN_STATE_FINISH_MIGRATE, RUN_STATE_RUNNING },
     { RUN_STATE_FINISH_MIGRATE, RUN_STATE_PAUSED },
-- 
1.8.3.1