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e40d3709c0
Lei Chen reported a bug with CLOCK_MONOTONIC_COARSE having inconsistencies when NTP is adjusting the clock frequency. This has gone seemingly undetected for ~15 years, illustrating a clear gap in our testing. The skew_consistency test is intended to catch this sort of problem, but was focused on only evaluating CLOCK_MONOTONIC, and thus missed the problem on CLOCK_MONOTONIC_COARSE. So adjust the test to run with all clockids for 60 seconds each instead of 10 minutes with just CLOCK_MONOTONIC. Reported-by: Lei Chen <lei.chen@smartx.com> Signed-off-by: John Stultz <jstultz@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20250320200306.1712599-2-jstultz@google.com Closes: https://lore.kernel.org/lkml/20250310030004.3705801-1-lei.chen@smartx.com/
76 lines
1.8 KiB
C
76 lines
1.8 KiB
C
/* ADJ_FREQ Skew consistency test
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* by: john stultz (johnstul@us.ibm.com)
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* (C) Copyright IBM 2012
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* Licensed under the GPLv2
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*
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* NOTE: This is a meta-test which cranks the ADJ_FREQ knob back
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* and forth and watches for consistency problems. Thus this test requires
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* that the inconsistency-check tests be present in the same directory it
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* is run from.
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*
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* To build:
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* $ gcc skew_consistency.c -o skew_consistency -lrt
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/time.h>
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#include <sys/timex.h>
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#include <time.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <string.h>
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#include <sys/wait.h>
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#include "../kselftest.h"
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int main(int argc, char **argv)
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{
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struct timex tx;
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int ret, ppm;
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pid_t pid;
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printf("Running Asynchronous Frequency Changing Tests...\n");
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pid = fork();
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if (!pid)
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return system("./inconsistency-check -t 60");
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ppm = 500;
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ret = 0;
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while (pid != waitpid(pid, &ret, WNOHANG)) {
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ppm = -ppm;
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tx.modes = ADJ_FREQUENCY;
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tx.freq = ppm << 16;
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adjtimex(&tx);
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usleep(500000);
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}
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/* Set things back */
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tx.modes = ADJ_FREQUENCY;
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tx.offset = 0;
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adjtimex(&tx);
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if (ret) {
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printf("[FAILED]\n");
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ksft_exit_fail();
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}
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printf("[OK]\n");
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ksft_exit_pass();
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}
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