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| author | Ingo Molnar <mingo@kernel.org> | 2012-08-04 21:21:14 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-08-05 12:37:14 +0200 |
| commit | 1d17d17484d40f2d5b35c79518597a2b25296996 (patch) | |
| tree | a11000cb9a7197b5d70573d0faa417cb36ba0e4b /kernel | |
| parent | e7882d6c40874a5b5033ca85f7508a602a60b662 (diff) | |
| download | linux-stable-1d17d17484d40f2d5b35c79518597a2b25296996.tar.gz linux-stable-1d17d17484d40f2d5b35c79518597a2b25296996.tar.bz2 linux-stable-1d17d17484d40f2d5b35c79518597a2b25296996.zip | |
time: Fix adjustment cleanup bug in timekeeping_adjust()
Tetsuo Handa reported that sporadically the system clock starts
counting up too quickly which is enough to confuse the hangcheck
timer to print a bogus stall warning.
Commit 2a8c0883 "time: Move xtime_nsec adjustment underflow handling
timekeeping_adjust" overlooked this exit path:
} else
return;
which should really be a proper exit sequence, fixing the bug as a
side effect.
Also make the flow more readable by properly balancing curly
braces.
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> wrote:
Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> wrote:
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: john.stultz@linaro.org
Cc: a.p.zijlstra@chello.nl
Cc: richardcochran@gmail.com
Cc: prarit@redhat.com
Link: http://lkml.kernel.org/r/20120804192114.GA28347@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/timekeeping.c | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 2988bc819187..e16af197a2bc 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -923,20 +923,22 @@ static void timekeeping_adjust(struct timekeeper *tk, s64 offset) if (likely(error <= interval)) adj = 1; else - adj = timekeeping_bigadjust(tk, error, &interval, - &offset); - } else if (error < -interval) { - /* See comment above, this is just switched for the negative */ - error >>= 2; - if (likely(error >= -interval)) { - adj = -1; - interval = -interval; - offset = -offset; - } else - adj = timekeeping_bigadjust(tk, error, &interval, - &offset); - } else - return; + adj = timekeeping_bigadjust(tk, error, &interval, &offset); + } else { + if (error < -interval) { + /* See comment above, this is just switched for the negative */ + error >>= 2; + if (likely(error >= -interval)) { + adj = -1; + interval = -interval; + offset = -offset; + } else { + adj = timekeeping_bigadjust(tk, error, &interval, &offset); + } + } else { + goto out_adjust; + } + } if (unlikely(tk->clock->maxadj && (tk->mult + adj > tk->clock->mult + tk->clock->maxadj))) { @@ -999,6 +1001,7 @@ static void timekeeping_adjust(struct timekeeper *tk, s64 offset) tk->xtime_nsec -= offset; tk->ntp_error -= (interval - offset) << tk->ntp_error_shift; +out_adjust: /* * It may be possible that when we entered this function, xtime_nsec * was very small. Further, if we're slightly speeding the clocksource |