selftests/timers: Add leapcrash test from the timetest suite

This change adds the leapcrash test which tests to see if a
leapsecond deadlock which was observed from 2.6.26 to 3.3
is present on this system.

Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Tested-by: NPrarit Bhargava <prarit@redhat.com>
Signed-off-by: NShuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/timers/Makefile

@@ -5,7 +5,7 @@ LDFLAGS += -lrt -lpthread
 bins = posix_timers nanosleep inconsistency-check nsleep-lat raw_skew \
 	set-timer-lat threadtest mqueue-lat valid-adjtimex \
 	alarmtimer-suspend change_skew skew_consistency clocksource-switch \
-	leap-a-day
+	leap-a-day leapcrash
 
 all: ${bins}
 
@@ -31,6 +31,7 @@ run_destructive_tests: run_tests
 	./skew_consistency
 	./clocksource-switch
 	./leap-a-day -s -i 10
+	./leapcrash
 
 clean:
 	rm -f ${bins}

tools/testing/selftests/timers/leapcrash.c

+/* Demo leapsecond deadlock
+ *              by: John Stultz (john.stultz@linaro.org)
+ *              (C) Copyright IBM 2012
+ *              (C) Copyright 2013, 2015 Linaro Limited
+ *              Licensed under the GPL
+ *
+ * This test demonstrates leapsecond deadlock that is possibe
+ * on kernels from 2.6.26 to 3.3.
+ *
+ * WARNING: THIS WILL LIKELY HARDHANG SYSTEMS AND MAY LOSE DATA
+ * RUN AT YOUR OWN RISK!
+ *  To build:
+ *	$ gcc leapcrash.c -o leapcrash -lrt
+ */
+
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <sys/time.h>
+#include <sys/timex.h>
+#include <string.h>
+#include <signal.h>
+#ifdef KTEST
+#include "../kselftest.h"
+#else
+static inline int ksft_exit_pass(void)
+{
+	exit(0);
+}
+static inline int ksft_exit_fail(void)
+{
+	exit(1);
+}
+#endif
+
+
+
+/* clear NTP time_status & time_state */
+int clear_time_state(void)
+{
+	struct timex tx;
+	int ret;
+
+	/*
+	 * We have to call adjtime twice here, as kernels
+	 * prior to 6b1859dba01c7 (included in 3.5 and
+	 * -stable), had an issue with the state machine
+	 * and wouldn't clear the STA_INS/DEL flag directly.
+	 */
+	tx.modes = ADJ_STATUS;
+	tx.status = STA_PLL;
+	ret = adjtimex(&tx);
+
+	tx.modes = ADJ_STATUS;
+	tx.status = 0;
+	ret = adjtimex(&tx);
+
+	return ret;
+}
+
+/* Make sure we cleanup on ctrl-c */
+void handler(int unused)
+{
+	clear_time_state();
+	exit(0);
+}
+
+
+int main(void)
+{
+	struct timex tx;
+	struct timespec ts;
+	time_t next_leap;
+	int count = 0;
+
+	setbuf(stdout, NULL);
+
+	signal(SIGINT, handler);
+	signal(SIGKILL, handler);
+	printf("This runs for a few minutes. Press ctrl-c to stop\n");
+
+	clear_time_state();
+
+
+	/* Get the current time */
+	clock_gettime(CLOCK_REALTIME, &ts);
+
+	/* Calculate the next possible leap second 23:59:60 GMT */
+	next_leap = ts.tv_sec;
+	next_leap += 86400 - (next_leap % 86400);
+
+	for (count = 0; count < 20; count++) {
+		struct timeval tv;
+
+
+		/* set the time to 2 seconds before the leap */
+		tv.tv_sec = next_leap - 2;
+		tv.tv_usec = 0;
+		if (settimeofday(&tv, NULL)) {
+			printf("Error: You're likely not running with proper (ie: root) permissions\n");
+			return ksft_exit_fail();
+		}
+		tx.modes = 0;
+		adjtimex(&tx);
+
+		/* hammer on adjtime w/ STA_INS */
+		while (tx.time.tv_sec < next_leap + 1) {
+			/* Set the leap second insert flag */
+			tx.modes = ADJ_STATUS;
+			tx.status = STA_INS;
+			adjtimex(&tx);
+		}
+		clear_time_state();
+		printf(".");
+	}
+	printf("[OK]\n");
+	return ksft_exit_pass();
+}