diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index d36afc58ee1d..8bc9edb40b78 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -238,9 +238,10 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
 	 * kernel_wait4() will also block until our children traced from the
 	 * parent namespace are detached and become EXIT_DEAD.
 	 */
+	/* Task work must not busy-loop the reaper, see signal_pending(). */
+	guard(no_notify_signal)();
 	do {
 		clear_thread_flag(TIF_SIGPENDING);
-		clear_thread_flag(TIF_NOTIFY_SIGNAL);
 		rc = kernel_wait4(-1, NULL, __WALL, NULL);
 	} while (rc != -ECHILD);