diff options
| author | Paul E. McKenney | 2023-06-07 11:59:49 -0700 |
|---|---|---|
| committer | Paul E. McKenney | 2023-07-14 15:17:09 -0700 |
| commit | e40806e9bcf8aaa86dbf0d484e7cf3cfa09cb86c (patch) | |
| tree | 3fa226db7247505724ef7d64de6c1684b37aa8f7 /kernel/time | |
| parent | 06c2afb862f9da8dc5efa4b6076a0e48c3fbaaa5 (diff) | |
clocksource: Handle negative skews in "skew is too large" messages
The nanosecond-to-millisecond skew computation uses unsigned arithmetic,
which produces user-unfriendly large positive numbers for negative skews.
Therefore, use signed arithmetic for this computation in order to preserve
the negativity.
Reported-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Reported-by: Feng Tang <feng.tang@intel.com>
Fixes: dd029269947a ("clocksource: Improve "skew is too large" messages")
Reviewed-by: Feng Tang <feng.tang@intel.com>
Tested-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/clocksource.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 88cbc1181b23..c108ed8a9804 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -473,8 +473,8 @@ static void clocksource_watchdog(struct timer_list *unused) /* Check the deviation from the watchdog clocksource. */ md = cs->uncertainty_margin + watchdog->uncertainty_margin; if (abs(cs_nsec - wd_nsec) > md) { - u64 cs_wd_msec; - u64 wd_msec; + s64 cs_wd_msec; + s64 wd_msec; u32 wd_rem; pr_warn("timekeeping watchdog on CPU%d: Marking clocksource '%s' as unstable because the skew is too large:\n", @@ -483,8 +483,8 @@ static void clocksource_watchdog(struct timer_list *unused) watchdog->name, wd_nsec, wdnow, wdlast, watchdog->mask); pr_warn(" '%s' cs_nsec: %lld cs_now: %llx cs_last: %llx mask: %llx\n", cs->name, cs_nsec, csnow, cslast, cs->mask); - cs_wd_msec = div_u64_rem(cs_nsec - wd_nsec, 1000U * 1000U, &wd_rem); - wd_msec = div_u64_rem(wd_nsec, 1000U * 1000U, &wd_rem); + cs_wd_msec = div_s64_rem(cs_nsec - wd_nsec, 1000 * 1000, &wd_rem); + wd_msec = div_s64_rem(wd_nsec, 1000 * 1000, &wd_rem); pr_warn(" Clocksource '%s' skewed %lld ns (%lld ms) over watchdog '%s' interval of %lld ns (%lld ms)\n", cs->name, cs_nsec - wd_nsec, cs_wd_msec, watchdog->name, wd_nsec, wd_msec); if (curr_clocksource == cs) |