[PATCH 5/5] selftests: timers: Add leap-second timer edge testing to leap-a-day.c

From: John Stultz
Date: Thu Jun 11 2015 - 18:55:35 EST


Prarit reported an issue w/ timers around the leapsecond, where
a timer set for Midnight UTC (00:00:00) might fire a second early
right before the leapsecond (23:59:60 - though it appears as a
repeated 23:59:59) is applied.

So I've updated the leap-a-day.c test to integrate a similar
test, where we set a timer and check if it triggers at the
right time, and if the ntp state transition is managed
properly.

Cc: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Cc: Richard Cochran <richardcochran@xxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Jiri Bohac <jbohac@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
Reported-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Reported-by: Prarit Bhargava <prarit@xxxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
---
tools/testing/selftests/timers/leap-a-day.c | 76 +++++++++++++++++++++++++++--
1 file changed, 72 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/timers/leap-a-day.c b/tools/testing/selftests/timers/leap-a-day.c
index b8272e6..331c4f7 100644
--- a/tools/testing/selftests/timers/leap-a-day.c
+++ b/tools/testing/selftests/timers/leap-a-day.c
@@ -44,6 +44,7 @@
#include <time.h>
#include <sys/time.h>
#include <sys/timex.h>
+#include <sys/errno.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
@@ -63,6 +64,9 @@ static inline int ksft_exit_fail(void)
#define NSEC_PER_SEC 1000000000ULL
#define CLOCK_TAI 11

+time_t next_leap;
+int error_found;
+
/* returns 1 if a <= b, 0 otherwise */
static inline int in_order(struct timespec a, struct timespec b)
{
@@ -134,6 +138,34 @@ void handler(int unused)
exit(0);
}

+void sigalarm(int signo)
+{
+ struct timex tx;
+ char buf[26];
+ int ret;
+
+ tx.modes = 0;
+ ret = adjtimex(&tx);
+
+ ctime_r(&tx.time.tv_sec, buf);
+ buf[strlen(buf)-1] = 0; /*remove trailing\n */
+ printf("%s + %6ld us (%i)\t%s - TIMER FIRED\n",
+ buf,
+ tx.time.tv_usec,
+ tx.tai,
+ time_state_str(ret));
+
+ if (tx.time.tv_sec < next_leap) {
+ printf("Error: Early timer expiration!\n");
+ error_found = 1;
+ }
+ if (ret != TIME_WAIT) {
+ printf("Error: Incorrect NTP state?\n");
+ error_found = 1;
+ }
+}
+
+
/* Test for known hrtimer failure */
void test_hrtimer_failure(void)
{
@@ -144,12 +176,19 @@ void test_hrtimer_failure(void)
clock_nanosleep(CLOCK_REALTIME, TIMER_ABSTIME, &target, NULL);
clock_gettime(CLOCK_REALTIME, &now);

- if (!in_order(target, now))
+ if (!in_order(target, now)) {
printf("ERROR: hrtimer early expiration failure observed.\n");
+ error_found = 1;
+ }
}

int main(int argc, char **argv)
{
+ timer_t tm1;
+ struct itimerspec its1;
+ struct sigevent se;
+ struct sigaction act;
+ int signum = SIGRTMAX;
int settime = 0;
int tai_time = 0;
int insert = 1;
@@ -191,6 +230,12 @@ int main(int argc, char **argv)
signal(SIGINT, handler);
signal(SIGKILL, handler);

+ /* Set up timer signal handler: */
+ sigfillset(&act.sa_mask);
+ act.sa_flags = 0;
+ act.sa_handler = sigalarm;
+ sigaction(signum, &act, NULL);
+
if (iterations < 0)
printf("This runs continuously. Press ctrl-c to stop\n");
else
@@ -201,7 +246,7 @@ int main(int argc, char **argv)
int ret;
struct timespec ts;
struct timex tx;
- time_t now, next_leap;
+ time_t now;

/* Get the current time */
clock_gettime(CLOCK_REALTIME, &ts);
@@ -251,10 +296,27 @@ int main(int argc, char **argv)

printf("Scheduling leap second for %s", ctime(&next_leap));

+ /* Set up timer */
+ printf("Setting timer for %s", ctime(&next_leap));
+ memset(&se, 0, sizeof(se));
+ se.sigev_notify = SIGEV_SIGNAL;
+ se.sigev_signo = signum;
+ se.sigev_value.sival_int = 0;
+ if (timer_create(CLOCK_REALTIME, &se, &tm1) == -1) {
+ printf("Error: timer_create failed\n");
+ return ksft_exit_fail();
+ }
+ its1.it_value.tv_sec = next_leap;
+ its1.it_value.tv_nsec = 0;
+ its1.it_interval.tv_sec = 0;
+ its1.it_interval.tv_nsec = 0;
+ timer_settime(tm1, TIMER_ABSTIME, &its1, NULL);
+
/* Wake up 3 seconds before leap */
ts.tv_sec = next_leap - 3;
ts.tv_nsec = 0;

+
while (clock_nanosleep(CLOCK_REALTIME, TIMER_ABSTIME, &ts, NULL))
printf("Something woke us up, returning to sleep\n");

@@ -276,6 +338,7 @@ int main(int argc, char **argv)
while (now < next_leap + 2) {
char buf[26];
struct timespec tai;
+ int ret;

tx.modes = 0;
ret = adjtimex(&tx);
@@ -308,8 +371,13 @@ int main(int argc, char **argv)
/* Note if kernel has known hrtimer failure */
test_hrtimer_failure();

- printf("Leap complete\n\n");
-
+ printf("Leap complete\n");
+ if (error_found) {
+ printf("Errors observed\n");
+ clear_time_state();
+ return ksft_exit_fail();
+ }
+ printf("\n");
if ((iterations != -1) && !(--iterations))
break;
}
--
1.9.1

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