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From: John Stultz <jstultz@google.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: John Stultz <jstultz@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	 Stephen Boyd <sboyd@kernel.org>,
	Anna-Maria Behnsen <anna-maria@linutronix.de>,
	 Frederic Weisbecker <frederic@kernel.org>,
	Shuah Khan <shuah@kernel.org>,
	 Miroslav Lichvar <mlichvar@redhat.com>,
	linux-kselftest@vger.kernel.org,  kernel-team@android.com,
	Lei Chen <lei.chen@smartx.com>
Subject: [PATCH v2 2/2] selftests/timers: Improve skew_consistency by testing with other clockids
Date: Thu, 20 Mar 2025 13:03:01 -0700	[thread overview]
Message-ID: <20250320200306.1712599-2-jstultz@google.com> (raw)
In-Reply-To: <20250320200306.1712599-1-jstultz@google.com>

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.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Anna-Maria Behnsen <anna-maria@linutronix.de>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: linux-kselftest@vger.kernel.org
Cc: kernel-team@android.com
Cc: Lei Chen <lei.chen@smartx.com>
Reported-by: Lei Chen <lei.chen@smartx.com>
Closes: https://lore.kernel.org/lkml/20250310030004.3705801-1-lei.chen@smartx.com/
Signed-off-by: John Stultz <jstultz@google.com>
---
 tools/testing/selftests/timers/skew_consistency.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/timers/skew_consistency.c b/tools/testing/selftests/timers/skew_consistency.c
index 83450145fe657..46c391d7f45dc 100644
--- a/tools/testing/selftests/timers/skew_consistency.c
+++ b/tools/testing/selftests/timers/skew_consistency.c
@@ -47,7 +47,7 @@ int main(int argc, char **argv)
 
 	pid = fork();
 	if (!pid)
-		return system("./inconsistency-check -c 1 -t 600");
+		return system("./inconsistency-check -t 60");
 
 	ppm = 500;
 	ret = 0;
-- 
2.49.0.395.g12beb8f557-goog


  reply	other threads:[~2025-03-20 20:03 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-20 20:03 [PATCH v2 1/2] time/timekeeping: Fix possible inconsistencies in _COARSE clockids John Stultz
2025-03-20 20:03 ` John Stultz [this message]
2025-03-25 11:32 ` Miroslav Lichvar
2025-03-27  9:22   ` Thomas Gleixner
2025-03-27 15:42     ` Miroslav Lichvar
2025-03-27 17:32       ` Thomas Gleixner
2025-03-31  7:53         ` Miroslav Lichvar
2025-04-17  2:55           ` John Stultz
2025-03-31 14:53       ` Miroslav Lichvar
2025-04-01  6:34         ` Thomas Gleixner
2025-04-01 11:19           ` Miroslav Lichvar
2025-04-01 18:29             ` Thomas Gleixner
2025-04-03  8:32               ` Miroslav Lichvar
2025-04-03 11:29                 ` Thomas Gleixner
2025-04-05 21:40                   ` [PATCH] timekeeping: Prevent coarse clocks going backwards Thomas Gleixner
2025-04-17  5:29                     ` John Stultz
2025-04-17 12:36                       ` Thomas Gleixner
2025-04-18  0:46                     ` John Stultz
2025-04-18  6:37                       ` Thomas Gleixner
2025-04-18  7:00                         ` Thomas Gleixner
2025-04-19  5:55                           ` John Stultz
2025-04-18 18:40                         ` John Stultz
2025-04-19  5:46                           ` [PATCH v3] " John Stultz

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