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| author | John Stultz <john.stultz@linaro.org> | 2014-11-24 20:35:45 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-11-25 07:18:34 +0100 |
| commit | cb2aa63469f81426c7406227be70b628b42f7a05 (patch) | |
| tree | d60788e5bc21d11592a0e3c42c44443789f4dd6b /kernel/time | |
| parent | 21b6c0512e8aca75ce76365e1aef9fb16e007100 (diff) | |
| download | linux-stable-cb2aa63469f81426c7406227be70b628b42f7a05.tar.gz linux-stable-cb2aa63469f81426c7406227be70b628b42f7a05.tar.bz2 linux-stable-cb2aa63469f81426c7406227be70b628b42f7a05.zip | |
time: Fix sign bug in NTP mult overflow warning
In commit 6067dc5a8c2b ("time: Avoid possible NTP adjustment
mult overflow") a new check was added to watch for adjustments
that could cause a mult overflow.
Unfortunately the check compares a signed with unsigned value
and ignored the case where the adjustment was negative, which
causes spurious warn-ons on some systems (and seems like it
would result in problematic time adjustments there as well, due
to the early return).
Thus this patch adds a check to make sure the adjustment is
positive before we check for an overflow, and resovles the issue
in my testing.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Debugged-by: pang.xunlei <pang.xunlei@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1416890145-30048-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/timekeeping.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 29a7d6709da1..2dc0646258ae 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1330,7 +1330,7 @@ static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk, * * XXX - TODO: Doc ntp_error calculation. */ - if (tk->tkr.mult + mult_adj < mult_adj) { + if ((mult_adj > 0) && (tk->tkr.mult + mult_adj < mult_adj)) { /* NTP adjustment caused clocksource mult overflow */ WARN_ON_ONCE(1); return; |