Re: [PATCH 1/2] cpufreq: serialize calls to __cpufreq_governor()

[Prarit Bhargava <prarit@redhat.com>]

On 10/10/2014 05:04 AM, Viresh Kumar wrote:
> On 8 October 2014 18:16, Prarit Bhargava <prarit@redhat.com> wrote:
>> On 10/08/2014 03:04 AM, Viresh Kumar wrote:
> 
>>> The last state of my branch: cpufreq/governor-fixes you tested had
>>> few bugs in it and so you weren't able to even tests things up.
>>>
>>> I couldn't manage to test my patches on a multi-cluster system
>>> (couldn't get it up yet :( ), but was able to do that on a dual-core
>>> ARM-cortexA15 board. And could simply find the bugs there.
>>>
>>> I have updated my branch with the changes now and it would be
>>> great if you can confirm if they fix your issues or not.
>>>
>>> git://git.linaro.org/people/viresh.kumar/linux.git cpufreq/governor-fixes
> 
> Robert/Prarit,
> 
> I thought you guys would test this very quickly as it had been hanging since
> long time. What happened ?
> 
>> Hey Viresh, this is on my plate for today.  It does look like the panic I sent
>> you yesterday in email does occur when your patches are put into the latest
>> upstream kernel :(.
> 
> I have tested my patches over mainline only, i.e. v3.17 .
> 
> Even the branch I mentioned above is based on that.
> 

Yep, I get that panic doing a very simple

#!/bin/bash

i=0
while [ True ]; do
        i=$((i+1))
        echo "ondemand" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor &
        echo "performance" > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor &
        echo "ondemand" > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor &
        echo "performance" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor &
        if [ $((i % 100)) = 0 ]; then
                echo $i
        fi
done

The blocking issue that I have (soon to be resolved I hope) is

http://marc.info/?l=linux-kernel&m=141286895623716&w=2

which is preventing me from doing any LOCKDEP analysis on this system.

I'm working on all of the above right now ...

P.