linux/tools/testing/selftests/timers/leapcrash.c
Shuah Khan b841065043 selftests: timers: drop support for !KTEST case
There is no need to keep timers tests in sync with external timers
repo. Drop support for !KTEST to support for building and running
timers tests without kselftest framework.

Reference: https://lkml.org/lkml/2017/8/10/952
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Acked-by: John Stultz <john.stultz@linaro.org>
2017-08-22 11:15:59 -06:00

108 lines
2.2 KiB
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>
#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(".");
}
printf("[OK]\n");
return ksft_exit_pass();
}