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From: Nathan Lynch <nathanl@linux.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: [PATCH 1/2] powerpc/64s: Fix crashes when toggling stf barrier
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Date: Tue, 04 May 2021 21:55:25 -0500
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Michael Ellerman <mpe@ellerman.id.au> writes:
> Nathan Lynch <nathanl@linux.ibm.com> writes:
>> post_mobility_fixup() does cpus_read_unlock() before calling
>> pseries_setup_security_mitigations(), I think that will need to be
>> changed?
>
> I don't think so.
>
> I'm using stop_machine_cpuslocked() but that's because I'm a goose and
> forgot to switch to stop_machine() after I reworked the code to not take
> cpus_read_lock() by hand. I really shouldn't send patches after 11pm.
>
> I don't think it's important to keep the cpus lock held from where we
> take it in post_mobility_fixup(). If some CPUs come or go between there
> and here that's fine.

Yes, agreed.