time: Fix adjustment cleanup bug in timekeeping_adjust() (1d17d174) · Commits · 戴 / test

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 "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>

kernel/time/timekeeping.c

+17 −14

Original line number	Diff line number	Diff line
		@@ -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) {
		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;
		} 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

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