migration: fix migrate_cancel multifd migration leads destination hung forever

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@tencent.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <1561468699-9819-4-git-send-email-ivanren@tencent.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
Ivan Ren 2019-06-25 21:18:19 +08:00 committed by Juan Quintela
parent 3c3ca25d1f
commit f193bc0c53
1 changed files with 5 additions and 0 deletions

View File

@ -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));