Hi John, some small typos below, others should be OK. On Tue, Aug 23, 2016 at 04:08:22PM -0700, John Stultz wrote: > It was reported that hibernation could fail on the 2nd attempt, > where the system 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 showed that the problem is triggered by > setting /sys/power/pm_trace to 1 before the 1st hibernation. > > Since once pm_trace is enabled, the rtc becomes unmeaningful > after suspend, and meanwhile some BIOSes would like to adjust > the 'invalid' tsc(e.g, smaller than 1970) to the release date I checked the previous commit log, and I have made a mistake, it should be: s/tsc/RTC > of that motherboard during POST stage, thus after resumed, it > may seem that the system had a significant long sleep time might > due to meaningless tsc or RTC delta. s/tsc or RTC/RTC > > Then in timekeeping_resume -> tk_debug_account_sleep_time, if > the bit31 of the sleep time happened to be set to 1, the fls > returns 32 and then we add 1 to sleep_time_bin[32], which > caused a memory overwritten. > > As depicted by System.map: > 0xffffffff81c9d080 b sleep_time_bin > 0xffffffff81c9d100 B dma_spin_lock > the dma_spin_lock.val is set to 1, which caused this problem. > > This patch adds a sanity check in tk_debug_account_sleep_time() > to ensure we don't index past the sleep_time_bin array. > BTW, I've also post a fix to deal with pm_trace which might break timekeeping at: https://patchwork.kernel.org/patch/9287347/ could you please hel take a glance? thanks. Yu -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html