Re: [v3.10-rc1] WARNING: at kernel/rcutree.c:502

[BjÃrn Mork]

"Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> writes:
> On Sun, May 12, 2013 at 05:55:00PM +0200, BjÃrn Mork wrote:
>> "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> writes:
>> > On Sun, May 12, 2013 at 11:08:50AM +0200, BjÃrn Mork wrote:
>> >> Hello,
>> >> 
>> >> got the splat below when running powertop on plain v3.10-rc1
>> >> (i.e. without my previously mentioned revert patch or any other extra
>> >> patches).  Config attached.
>> >
>> > OK, it looks like you have context-tracking enabled, so you might be
>> > hitting a bug that Steven Rostedt found a few days ago.  Could you
>> > please try out his fix below?
>> 
>> Thanks for the quick reply, but I'm afraid that patch had no effect on
>> the warning I got. It's still there.
>
> Other than wondering whether powertop has issues similar to the bug
> Steven Rostedt located, I must confess myself clueless.  Here are some
> diagnostics I can suggest:
>
> 1.	Run in 32-bit mode.  This disables some of the new adaptive-ticks
> 	functionality, so might give a probabilistic indication of where
> 	the bug lies.
>
> 2.	The standard fallback of bisection.
>
> Would you be willing to do either of these?

Willing, yes. But it will take some time before I am able to do either
unless I can recreate the problem in a virtual machine.  I assume that
you by " 32-bit mode" mean a 32bit kernel?  I'm not exactly set up to
run that on my laptop.  Bisection will be less work.

To be honest, I don't even know how old this thing is.  It could be
totally unrelated to your recent changes for all I know. Running
powertop is something I do once every 6 kernel releases or something
like that...

I'll see what I can come up with.  Thanks for your attention.


BjÃrn
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