| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 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 */ |
| 28 | int 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 */ |
| 51 | void handler(int unused) |
| 52 | { |
| 53 | clear_time_state(); |
| 54 | exit(0); |
| 55 | } |
| 56 | |
| 57 | |
| 58 | int 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 | } |
| 105 | printf("[OK]\n"); |
| 106 | return ksft_exit_pass(); |
| 107 | } |