In multi-core system, if the clock is not sync perfectly, it will make cycle_last that recorded by CPU-A is a little more than cycle_now that read by CPU-B. With the negative result, hrtimer_update_base() return a huge and wrong time. It leads to the cpu can not finish the while loop in hrtimer_interrupt() until the real nowtime which is returned from ktime_get() catch up with the wrong time on clock monotonic base.
Fix it by select config CLOCKSOURCE_VALIDATE_LAST_CYCLE. Cc: Thomas Gleixner <t...@linutronix.de> Yang Yingliang (2): clocksource: replace cycle_last validation with an equal way arm64: validate the cycle_last to prevent time going backwards arch/arm64/Kconfig | 1 + kernel/time/timekeeping_internal.h | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
