linux-kernel - Re: [PATCH] x86/fpu: Fix irq_fpu_usable() to return false during CPU onlining

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Message-ID: <aCxMXqQmHGU06l-O@gmail.com>
Date: Tue, 20 May 2025 11:33:18 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Eric Biggers <ebiggers@...nel.org>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org,
	linux-crypto@...r.kernel.org, linux-pm@...r.kernel.org,
	Borislav Petkov <bp@...en8.de>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ayush Jain <Ayush.Jain3@....com>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	Ard Biesheuvel <ardb@...nel.org>
Subject: Re: [PATCH] x86/fpu: Fix irq_fpu_usable() to return false during CPU
 onlining


* Eric Biggers <ebiggers@...nel.org> wrote:

> Or we could use DEFINE_PER_CPU() = true in patch 1, then revert that 
> in patch 2 and replace it with the line in fpu__init_cpu().  But 
> again I think the split would be more likely to create problems than 
> solve them.

Well, my request would be for the first patch to simply mimic current 
(and buggy) behavior as much as reasonably possible (obviously the 
effects of BSS zeroing shouldn't be mimiced 100%) - and the second 
patch to fix the initialization-ordering bug.

Thanks,

	Ingo