Re: [PATCH][v2] timekeeping: Fix memory overwrite of sleep_time_bin array

From: Thomas Gleixner
Date: Tue Jul 19 2016 - 04:38:40 EST

On Tue, 19 Jul 2016, Chen Yu wrote:

> It is reported the hibernation fails at 2nd attempt, which
> hangs at hibernate() -> syscore_resume() -> i8237A_resume()
> -> claim_dma_lock(), because the lock has already been taken.
> However there is actually no other process would like to grab
> this lock on that problematic platform.
> Further investigation shows that, the problem is caused by setting
> /sys/power/pm_trace to 1 before the 1st hibernation, since once
> pm_trace is enabled, the rtc becomes an unmeaningful value after resumed,

So why is the RTC value useless if pm_trace is enabled? I really have a hard
time to understand why pm_trace would affect the sleep time readout from RTC.