On Fri, 2017-06-30 at 17:28 +1000, Nicholas Piggin wrote: > On Fri, 30 Jun 2017 10:52:18 +0530 > Abdul Haleem <abdhalee@xxxxxxxxxxxxxxxxxx> wrote: > > > On Fri, 2017-06-30 at 00:45 +1000, Nicholas Piggin wrote: > > > On Thu, 29 Jun 2017 20:23:05 +1000 > > > Nicholas Piggin <npiggin@xxxxxxxxx> wrote: > > > > > > > On Thu, 29 Jun 2017 19:36:14 +1000 > > > > Nicholas Piggin <npiggin@xxxxxxxxx> wrote: > > > > > > > > I don't *think* the replay-wakeup-interrupt patch is directly involved, but > > > > > it's likely to be one of the idle patches. > > > > > > Okay this turned out to be misconfigured sleep states I added for the > > > simulator, sorry for the false alarm. > > > > > > > Although you have this in the backtrace. I wonder if that's a stuck > > > > lock in rcu_process_callbacks? > > > > > > So this spinlock becomes top of the list of suspects. Can you try > > > enabling lockdep and try to reproduce it? > > > > Yes, recreated again with CONFIG_LOCKDEP=y & CONFIG_DEBUG_LOCKDEP=y set. > > I do not see any difference in trace messages with and without LOCKDEP > > enabled. > > > > Please find the attached log file. > > Can you get an rcu_invoke_callback event trace that Paul suggested? Yes, I was able to collect the perf data for rcu_invoke_callback event on recent next kernel (4.12.0-next-20170705). the issue is rare to hit. After booting the next kernel, I started this command 'perf record -e rcu:rcu_invoke_callback -a -g -- cat' and waited for 30 minutes. five minutes after seeing the stalls messages, I did CTRL-C to end the perf command. @Nicholas : the perf.data report is too huge to attach here, shall I ping you the internal location of file on slack/mail ? Also the machine is in the same state if you want to use it ? > > Does this bug show up with just the powerpc next branch? > > Thanks, > Nick > -- Regard's Abdul Haleem IBM Linux Technology Centre -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
