selftests/timers/posix-timers: Validate overrun after unblock

When a timer signal is blocked and later unblocked then one signal should
be delivered with the correct number of overruns since the timer was queued.

Validate that behaviour.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>

tools/testing/selftests/timers/posix_timers.c

@@ -540,10 +540,66 @@ static void check_gettime(int which, const char *name)
 	ksft_test_result(wraps > 1, "check_gettime %s\n", name);
 }
 
+static void check_overrun(int which, const char *name)
+{
+	struct timespec start, now;
+	struct tmrsig tsig = { };
+	struct itimerspec its;
+	struct sigaction sa;
+	struct sigevent sev;
+	timer_t timerid;
+	sigset_t set;
+
+	sa.sa_flags = SA_SIGINFO;
+	sa.sa_sigaction = siginfo_handler;
+	sigemptyset(&sa.sa_mask);
+	if (sigaction(SIGUSR1, &sa, NULL))
+		fatal_error(name, "sigaction()");
+
+	/* Block the signal */
+	sigemptyset(&set);
+	sigaddset(&set, SIGUSR1);
+	if (sigprocmask(SIG_BLOCK, &set, NULL))
+		fatal_error(name, "sigprocmask(SIG_BLOCK)");
+
+	memset(&sev, 0, sizeof(sev));
+	sev.sigev_notify = SIGEV_SIGNAL;
+	sev.sigev_signo = SIGUSR1;
+	sev.sigev_value.sival_ptr = &tsig;
+	if (timer_create(which, &sev, &timerid))
+		fatal_error(name, "timer_create()");
+
+	/* Start the timer to expire in 100ms and 100ms intervals */
+	its.it_value.tv_sec = 0;
+	its.it_value.tv_nsec = 100000000;
+	its.it_interval.tv_sec = 0;
+	its.it_interval.tv_nsec = 100000000;
+	if (timer_settime(timerid, 0, &its, NULL))
+		fatal_error(name, "timer_settime()");
+
+	if (clock_gettime(which, &start))
+		fatal_error(name, "clock_gettime()");
+
+	do {
+		if (clock_gettime(which, &now))
+			fatal_error(name, "clock_gettime()");
+	} while (calcdiff_ns(now, start) < NSECS_PER_SEC);
+
+	/* Unblock it, which should deliver a signal */
+	if (sigprocmask(SIG_UNBLOCK, &set, NULL))
+		fatal_error(name, "sigprocmask(SIG_UNBLOCK)");
+
+	if (timer_delete(timerid))
+		fatal_error(name, "timer_delete()");
+
+	ksft_test_result(tsig.signals == 1 && tsig.overruns == 9,
+			 "check_overrun %s\n", name);
+}
+
 int main(int argc, char **argv)
 {
 	ksft_print_header();
-	ksft_set_plan(15);
+	ksft_set_plan(18);
 
 	ksft_print_msg("Testing posix timers. False negative may happen on CPU execution \n");
 	ksft_print_msg("based timers if other threads run on the CPU...\n");
@@ -574,6 +630,9 @@ int main(int argc, char **argv)
 	check_gettime(CLOCK_MONOTONIC, "CLOCK_MONOTONIC");
 	check_gettime(CLOCK_PROCESS_CPUTIME_ID, "CLOCK_PROCESS_CPUTIME_ID");
 	check_gettime(CLOCK_THREAD_CPUTIME_ID, "CLOCK_THREAD_CPUTIME_ID");
+	check_overrun(CLOCK_MONOTONIC, "CLOCK_MONOTONIC");
+	check_overrun(CLOCK_PROCESS_CPUTIME_ID, "CLOCK_PROCESS_CPUTIME_ID");
+	check_overrun(CLOCK_THREAD_CPUTIME_ID, "CLOCK_THREAD_CPUTIME_ID");
 
 	ksft_finished();
 }