cpus: Properly release the iothread lock when killing a dummy VCPU

This enables CPU unplug under qtest.

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190218092202.26683-2-david@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 1 insertions, 0 deletions

diff --git a/cpus.c b/cpus.c
index 154daf57dc..e83f72b48b 100644
--- a/cpus.c
+++ b/cpus.c
@@ -1333,6 +1333,7 @@ static void *qemu_dummy_cpu_thread_fn(void *arg)
         qemu_wait_io_event(cpu);
     } while (!cpu->unplug);
 
+    qemu_mutex_unlock_iothread();
     rcu_unregister_thread();
     return NULL;
 #endif