From: Peter Hilber <peter.hilber@opensynergy.com>
To: linux-kernel@vger.kernel.org
Cc: Peter Hilber <peter.hilber@opensynergy.com>,
John Stultz <jstultz@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Stephen Boyd <sboyd@kernel.org>,
"Christopher S. Hall" <christopher.s.hall@intel.com>
Subject: [RFC PATCH 1/7] timekeeping: Fix cross-timestamp interpolation on counter wrap
Date: Fri, 30 Jun 2023 19:10:44 +0200 [thread overview]
Message-ID: <20230630171052.985577-2-peter.hilber@opensynergy.com> (raw)
In-Reply-To: <20230630171052.985577-1-peter.hilber@opensynergy.com>
cycle_between() decides whether get_device_system_crosststamp() will
interpolate for older counter readings.
cycle_between() yields wrong results for a counter wrap-around where after
< before < test, and for the case after < test < before.
Fix the comparison logic.
Fixes: 2c756feb18d9 ("time: Add history to cross timestamp interface supporting slower devices")
Signed-off-by: Peter Hilber <peter.hilber@opensynergy.com>
---
kernel/time/timekeeping.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 266d02809dbb..8f35455b6250 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1186,7 +1186,7 @@ static bool cycle_between(u64 before, u64 test, u64 after)
{
if (test > before && test < after)
return true;
- if (test < before && before > after)
+ if (before > after && (test > before || test < after))
return true;
return false;
}
--
2.39.2
next prev parent reply other threads:[~2023-06-30 17:33 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-30 17:10 [RFC PATCH 0/7] Add virtio_rtc module and related changes Peter Hilber
2023-06-30 17:10 ` Peter Hilber [this message]
2023-07-07 22:51 ` [RFC PATCH 1/7] timekeeping: Fix cross-timestamp interpolation on counter wrap John Stultz
2023-07-27 10:21 ` Peter Hilber
2023-06-30 17:10 ` [RFC PATCH 2/7] timekeeping: Fix cross-timestamp interpolation corner case decision Peter Hilber
2023-07-07 23:02 ` John Stultz
2023-07-27 10:21 ` Peter Hilber
2023-06-30 17:10 ` [RFC PATCH 3/7] timekeeping: Fix cross-timestamp interpolation for non-x86 Peter Hilber
2023-07-07 23:31 ` John Stultz
2023-07-27 10:21 ` Peter Hilber
2023-06-30 17:10 ` [RFC PATCH 4/7] clocksource: arm_arch_timer: Export counter type, clocksource Peter Hilber
2023-07-03 8:13 ` Marc Zyngier
2023-07-27 10:22 ` Peter Hilber
2023-07-28 8:11 ` Marc Zyngier
2023-07-31 16:15 ` Peter Hilber
2023-06-30 17:10 ` [RFC PATCH 5/7] virtio_rtc: Add module and driver core Peter Hilber
2023-06-30 17:10 ` [RFC PATCH 6/7] virtio_rtc: Add PTP clocks Peter Hilber
2023-06-30 17:10 ` [RFC PATCH 7/7] virtio_rtc: Add Arm Generic Timer cross-timestamping Peter Hilber
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