From: Ivan Ren <renyime@xxxxxxxxx>
When migrate_cancel a multifd migration, if run sequence like this:
[source] [destination]
multifd_send_sync_main[finish]
multifd_recv_thread wait &p->sem_sync
shutdown to_dst_file
detect error from_src_file
send RAM_SAVE_FLAG_EOS[fail] [no chance to run multifd_recv_sync_main]
multifd_load_cleanup
join multifd receive thread forever
will lead destination qemu hung at following stack:
pthread_join
qemu_thread_join
multifd_load_cleanup
process_incoming_migration_co
coroutine_trampoline
Signed-off-by: Ivan Ren <ivanren@xxxxxxxxxxx>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@xxxxxxxxxx>
Reviewed-by: Juan Quintela <quintela@xxxxxxxxxx>
Message-Id: <1561468699-9819-4-git-send-email-ivanren@xxxxxxxxxxx>
Signed-off-by: Juan Quintela <quintela@xxxxxxxxxx>
---
migration/ram.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/migration/ram.c b/migration/ram.c
index eb6716710e..889148dd84 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1292,6 +1292,11 @@ int multifd_load_cleanup(Error **errp)
if (p->running) {
p->quit = true;
+ /*
+ * multifd_recv_thread may hung at MULTIFD_FLAG_SYNC handle code,
+ * however try to wakeup it without harm in cleanup phase.
+ */
+ qemu_sem_post(&p->sem_sync);
qemu_thread_join(&p->thread);
}
object_unref(OBJECT(p->c));
--
2.21.0
