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Date: Tue, 12 Mar 2024 10:06:06 -0700 (PDT)
From: "Christoph Lameter (Ampere)" <cl@linux.com>
To: Catalin Marinas <catalin.marinas@arm.com>
cc: Marek Szyprowski <m.szyprowski@samsung.com>, 
    Mark Rutland <mark.rutland@arm.com>, 
    "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>, 
    "Rafael J. Wysocki" <rafael@kernel.org>, Viresh Kumar <vireshk@kernel.org>, 
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    Matteo.Carlini@arm.com, Valentin.Schneider@arm.com, 
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    vanshikonda@os.amperecomputing.com, yang@os.amperecomputing.com, 
    Nishanth Menon <nm@ti.com>, Stephen Boyd <sboyd@kernel.org>
Subject: Re: [PATCH v3] ARM64: Dynamically allocate cpumasks and increase
 supported CPUs to 512
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On Mon, 11 Mar 2024, Christoph Lameter (Ampere) wrote:

> This could be an issue in the ARM64 arch code itself where there maybe an 
> assumption elsewhere that a cpumask can always store up to NR_CPU cpus and 
> not only nr_cpu_ids as OFFSTACK does.
>
> How can I exercise the opp driver in order to recreate the problem?
>
> I assume the opp driver is ARM specific? x86 defaults to OFFSTACK so if there 
> is an issue with OFFSTACK in opp then it should fail with kernel default 
> configuration on that platform.

I checked the ARM64 arch sources use of NR_CPUS and its all fine.

Also verified in my testing logs that CONFIG_PM_OPP was set in all tests.

No warnings in the kernel log during those tests.

How to reproduce this?