Hi Oliver, On Thu, Aug 18, 2016 at 12:36:51PM +0200, Oliver Neukum wrote: > On Thu, 2016-08-18 at 18:43 +0800, Chen Yu wrote: > > Previously we encountered some memory overflow issues due to > > the bogus sleep time brought by inconsistent rtc, which is > > triggered when pm_trace is enabled, please refer to: > > https://patchwork.kernel.org/patch/9286365/ > > It's improper in the first place to call __timekeeping_inject_sleeptime() > > in case that pm_trace is enabled simply because that "hash" time value > > will wreckage the timekeeping subsystem. > > Hi, > > do you know since when this bug exists? > I think as Xunlei mentioned, the memory overflow issue should exist since we changed timespec to timespec64 in timekeeping_debug, which should be in 3.17. But the bogus sleep time caused by pm_trace should always be there as long as we use rtc for sleep compensation. > > /** > > @@ -1662,6 +1668,12 @@ void timekeeping_resume(void) > > } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) { > > ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time); > > sleeptime_injected = true; > > + /* > > + * If rtc is used as persist clock thus it > > + * would be bogus when pm_trace is enabled. > > + */ > > + if (!persistent_clock_is_usable()) > > + sleeptime_injected = false; > > } > > > > if (sleeptime_injected) > > How about > > sleeptime_injected = persistent_clock_is_usable(); > OK, this is simpler, will do in next version.
thanks, Yu >
