diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h
index c7b67e379219..2902f6a78f8a 100644
--- a/tools/testing/selftests/kselftest_harness.h
+++ b/tools/testing/selftests/kselftest_harness.h
@@ -639,7 +639,8 @@ struct __test_metadata {
 	int termsig;
 	int passed;
 	int trigger; /* extra handler after the evaluation */
-	int timeout;
+	int timeout;	/* seconds to wait for test timeout */
+	bool timed_out;	/* did this test timeout instead of exiting? */
 	__u8 step;
 	bool no_print; /* manual trigger when TH_LOG_STREAM is not available */
 	struct __test_metadata *prev, *next;
@@ -696,15 +697,63 @@ static inline int __bail(int for_realz, bool no_print, __u8 step)
 	return 0;
 }
 
+struct __test_metadata *__active_test;
+static void __timeout_handler(int sig, siginfo_t *info, void *ucontext)
+{
+	struct __test_metadata *t = __active_test;
+
+	/* Sanity check handler execution environment. */
+	if (!t) {
+		fprintf(TH_LOG_STREAM,
+			"no active test in SIGARLM handler!?\n");
+		abort();
+	}
+	if (sig != SIGALRM || sig != info->si_signo) {
+		fprintf(TH_LOG_STREAM,
+			"%s: SIGALRM handler caught signal %d!?\n",
+			t->name, sig != SIGALRM ? sig : info->si_signo);
+		abort();
+	}
+
+	t->timed_out = true;
+	kill(t->pid, SIGKILL);
+}
+
 void __wait_for_test(struct __test_metadata *t)
 {
+	struct sigaction action = {
+		.sa_sigaction = __timeout_handler,
+		.sa_flags = SA_SIGINFO,
+	};
+	struct sigaction saved_action;
 	int status;
 
+	if (sigaction(SIGALRM, &action, &saved_action)) {
+		t->passed = 0;
+		fprintf(TH_LOG_STREAM,
+			"%s: unable to install SIGARLM handler\n",
+			t->name);
+		return;
+	}
+	__active_test = t;
+	t->timed_out = false;
 	alarm(t->timeout);
 	waitpid(t->pid, &status, 0);
 	alarm(0);
+	if (sigaction(SIGALRM, &saved_action, NULL)) {
+		t->passed = 0;
+		fprintf(TH_LOG_STREAM,
+			"%s: unable to uninstall SIGARLM handler\n",
+			t->name);
+		return;
+	}
+	__active_test = NULL;
 
-	if (WIFEXITED(status)) {
+	if (t->timed_out) {
+		t->passed = 0;
+		fprintf(TH_LOG_STREAM,
+			"%s: Test terminated by timeout\n", t->name);
+	} else if (WIFEXITED(status)) {
 		t->passed = t->termsig == -1 ? !WEXITSTATUS(status) : 0;
 		if (t->termsig != -1) {
 			fprintf(TH_LOG_STREAM,