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diff --git a/tools/testing/selftests/timers/leapcrash.c b/tools/testing/selftests/timers/leapcrash.c
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+/* 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 possible
+ * on kernels from 2.6.26 to 3.3.
+ *
+ * WARNING: THIS WILL LIKELY HARD HANG 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>
+#include "../kselftest.h"
+
+/* 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(".");
+ fflush(stdout);
+ }
+ printf("[OK]\n");
+ return ksft_exit_pass();
+}