Re: [BUG] Kernel splat when taking CPUs offline

[Viresh Kumar]

On 09-07-15, 02:13, Rafael J. Wysocki wrote:
> So the cpufreq driver's ->get() callback returns 0 for the given CPU and
> that's what triggers the WARN_ON().  And it most likely returns 0, because
> its internal data structure for that CPU is not present.
> 
> I *guess* that before the above commit policy was NULL in cpufreq_update_policy()
> and we didn't get to the point where ->get() was called.

I am not sure if that behavior should have changed at all.. Earlier we
were clearing per-cpu cpufreq_cpu_data for offline CPUs and so policy
would have been NULL for offline CPUs.

Now that per-cpu variable isn't cleared, but cpufreq_cpu_get() does
check if the CPU is part of policy->cpus or not, i.e. if it is
offline. And so policy should still be NULL for offline CPUs.

I think it might be related to what I chased down yesterday:

http://marc.info/?l=linux-kernel&m=143633485824975&w=2

@Steven: Can you please give this a try ?

-- 
viresh
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