diff --git a/lib/isc/unix/socket.c b/lib/isc/unix/socket.c
index 93bc148c59..fd733c049f 100644
--- a/lib/isc/unix/socket.c
+++ b/lib/isc/unix/socket.c
@@ -4138,7 +4138,7 @@ watcher(void *uap) {
 							&manager->open_max);
 				if (result != ISC_R_SUCCESS)
 					manager->open_max = 64;
-				manager->calls == 0;
+				manager->calls = 0;
 			}
 			for (pass = 0; pass < 2; pass++) {
 				dvp.dp_fds = manager->events;