diff --git a/qemu-nbd.c b/qemu-nbd.c
index b5751f853b..2c9754e5d6 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -215,7 +215,7 @@ static int find_partition(BlockBackend *blk, int partition,
 
 static void termsig_handler(int signum)
 {
-    state = TERMINATE;
+    atomic_cmpxchg(&state, RUNNING, TERMINATE);
     qemu_notify_event();
 }