Re: [PATCH V2 0/7] cpufreq: governors: Fix ABBA lockups

From: Viresh Kumar
Date: Thu Feb 04 2016 - 21:49:34 EST


On 05-02-16, 02:20, Shilpasri G Bhat wrote:
> I could see the previous lockdep warnings on pm/next and on top of patch[4].
> On Patch[5-7] I see the below lockdep trace on running './runme' on a Power8 box.

> [ 710.336130] Chain exists of:
> s_active#91 --> &dbs_data->mutex --> od_dbs_cdata.mutex
>
> [ 710.336376] Possible unsafe locking scenario:
>
> [ 710.336488] CPU0 CPU1
> [ 710.336577] ---- ----
> [ 710.336666] lock(od_dbs_cdata.mutex);
> [ 710.336778] lock(&dbs_data->mutex);
> [ 710.336911] lock(od_dbs_cdata.mutex);
> [ 710.337064] lock(s_active#91);
> [ 710.337176]

This is the same lockdep, just that we have added another mutex
(dbs_data->mutex) to it.

Have you tried if all the lockdeps go away with the 8th patch that I
provided yesterday ?

--
viresh