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1/* Demo leapsecond deadlock
2 * by: John Stultz (john.stultz@linaro.org)
3 * (C) Copyright IBM 2012
4 * (C) Copyright 2013, 2015 Linaro Limited
5 * Licensed under the GPL
6 *
7 * This test demonstrates leapsecond deadlock that is possibe
8 * on kernels from 2.6.26 to 3.3.
9 *
10 * WARNING: THIS WILL LIKELY HARDHANG SYSTEMS AND MAY LOSE DATA
11 * RUN AT YOUR OWN RISK!
12 * To build:
13 * $ gcc leapcrash.c -o leapcrash -lrt
14 */
15
16
17
18#include <stdio.h>
19#include <stdlib.h>
20#include <time.h>
21#include <sys/time.h>
22#include <sys/timex.h>
23#include <string.h>
24#include <signal.h>
25#include "../kselftest.h"
26
27/* clear NTP time_status & time_state */
28int clear_time_state(void)
29{
30 struct timex tx;
31 int ret;
32
33 /*
34 * We have to call adjtime twice here, as kernels
35 * prior to 6b1859dba01c7 (included in 3.5 and
36 * -stable), had an issue with the state machine
37 * and wouldn't clear the STA_INS/DEL flag directly.
38 */
39 tx.modes = ADJ_STATUS;
40 tx.status = STA_PLL;
41 ret = adjtimex(&tx);
42
43 tx.modes = ADJ_STATUS;
44 tx.status = 0;
45 ret = adjtimex(&tx);
46
47 return ret;
48}
49
50/* Make sure we cleanup on ctrl-c */
51void handler(int unused)
52{
53 clear_time_state();
54 exit(0);
55}
56
57
58int main(void)
59{
60 struct timex tx;
61 struct timespec ts;
62 time_t next_leap;
63 int count = 0;
64
65 setbuf(stdout, NULL);
66
67 signal(SIGINT, handler);
68 signal(SIGKILL, handler);
69 printf("This runs for a few minutes. Press ctrl-c to stop\n");
70
71 clear_time_state();
72
73
74 /* Get the current time */
75 clock_gettime(CLOCK_REALTIME, &ts);
76
77 /* Calculate the next possible leap second 23:59:60 GMT */
78 next_leap = ts.tv_sec;
79 next_leap += 86400 - (next_leap % 86400);
80
81 for (count = 0; count < 20; count++) {
82 struct timeval tv;
83
84
85 /* set the time to 2 seconds before the leap */
86 tv.tv_sec = next_leap - 2;
87 tv.tv_usec = 0;
88 if (settimeofday(&tv, NULL)) {
89 printf("Error: You're likely not running with proper (ie: root) permissions\n");
90 return ksft_exit_fail();
91 }
92 tx.modes = 0;
93 adjtimex(&tx);
94
95 /* hammer on adjtime w/ STA_INS */
96 while (tx.time.tv_sec < next_leap + 1) {
97 /* Set the leap second insert flag */
98 tx.modes = ADJ_STATUS;
99 tx.status = STA_INS;
100 adjtimex(&tx);
101 }
102 clear_time_state();
103 printf(".");
104 fflush(stdout);
105 }
106 printf("[OK]\n");
107 return ksft_exit_pass();
108}
1/* Demo leapsecond deadlock
2 * by: John Stultz (john.stultz@linaro.org)
3 * (C) Copyright IBM 2012
4 * (C) Copyright 2013, 2015 Linaro Limited
5 * Licensed under the GPL
6 *
7 * This test demonstrates leapsecond deadlock that is possibe
8 * on kernels from 2.6.26 to 3.3.
9 *
10 * WARNING: THIS WILL LIKELY HARDHANG SYSTEMS AND MAY LOSE DATA
11 * RUN AT YOUR OWN RISK!
12 * To build:
13 * $ gcc leapcrash.c -o leapcrash -lrt
14 */
15
16
17
18#include <stdio.h>
19#include <stdlib.h>
20#include <time.h>
21#include <sys/time.h>
22#include <sys/timex.h>
23#include <string.h>
24#include <signal.h>
25#ifdef KTEST
26#include "../kselftest.h"
27#else
28static inline int ksft_exit_pass(void)
29{
30 exit(0);
31}
32static inline int ksft_exit_fail(void)
33{
34 exit(1);
35}
36#endif
37
38
39
40/* clear NTP time_status & time_state */
41int clear_time_state(void)
42{
43 struct timex tx;
44 int ret;
45
46 /*
47 * We have to call adjtime twice here, as kernels
48 * prior to 6b1859dba01c7 (included in 3.5 and
49 * -stable), had an issue with the state machine
50 * and wouldn't clear the STA_INS/DEL flag directly.
51 */
52 tx.modes = ADJ_STATUS;
53 tx.status = STA_PLL;
54 ret = adjtimex(&tx);
55
56 tx.modes = ADJ_STATUS;
57 tx.status = 0;
58 ret = adjtimex(&tx);
59
60 return ret;
61}
62
63/* Make sure we cleanup on ctrl-c */
64void handler(int unused)
65{
66 clear_time_state();
67 exit(0);
68}
69
70
71int main(void)
72{
73 struct timex tx;
74 struct timespec ts;
75 time_t next_leap;
76 int count = 0;
77
78 setbuf(stdout, NULL);
79
80 signal(SIGINT, handler);
81 signal(SIGKILL, handler);
82 printf("This runs for a few minutes. Press ctrl-c to stop\n");
83
84 clear_time_state();
85
86
87 /* Get the current time */
88 clock_gettime(CLOCK_REALTIME, &ts);
89
90 /* Calculate the next possible leap second 23:59:60 GMT */
91 next_leap = ts.tv_sec;
92 next_leap += 86400 - (next_leap % 86400);
93
94 for (count = 0; count < 20; count++) {
95 struct timeval tv;
96
97
98 /* set the time to 2 seconds before the leap */
99 tv.tv_sec = next_leap - 2;
100 tv.tv_usec = 0;
101 if (settimeofday(&tv, NULL)) {
102 printf("Error: You're likely not running with proper (ie: root) permissions\n");
103 return ksft_exit_fail();
104 }
105 tx.modes = 0;
106 adjtimex(&tx);
107
108 /* hammer on adjtime w/ STA_INS */
109 while (tx.time.tv_sec < next_leap + 1) {
110 /* Set the leap second insert flag */
111 tx.modes = ADJ_STATUS;
112 tx.status = STA_INS;
113 adjtimex(&tx);
114 }
115 clear_time_state();
116 printf(".");
117 }
118 printf("[OK]\n");
119 return ksft_exit_pass();
120}