linux-kernel - Re: [PATCH 0/6] x86/fpu: don't abuse x86_task_fpu(PF_USER_WORKER) in .regset

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Message-ID: <20250815193356.GL11549@redhat.com>
Date: Fri, 15 Aug 2025 21:33:57 +0200
From: Oleg Nesterov <oleg@...hat.com>
To: Sohil Mehta <sohil.mehta@...el.com>
Cc: Dave Hansen <dave.hansen@...el.com>, Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...nel.org>,
	Jens Axboe <axboe@...nel.dk>, Peter Zijlstra <peterz@...radead.org>,
	Rick Edgecombe <rick.p.edgecombe@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org,
	x86@...nel.org, Mark Brown <broonie@...nel.org>
Subject: Re: [PATCH 0/6] x86/fpu: don't abuse x86_task_fpu(PF_USER_WORKER) in
 .regset_get() paths

On 08/15, Sohil Mehta wrote:
>
> I think it would be useful to categorize the impact of the "abuse" in
> the cover letter.

Yes, let me repeat that this is my fault.

>Is it going to cause kernel crashes, userspace crashes
> or just incorrect reporting?

Heh ;)

In the short term, I'd like to make your patch correct ;)

	[PATCH v3 2/2] x86/fpu: Update the debug flow for x86_task_fpu()
	https://lore.kernel.org/all/20250724013422.307954-2-sohil.mehta@intel.com/

(just in case, no, this series alone is not enough).

In the longer term, rightly or not I'd like to do other changes we have already
discussed. See my other emails in this thread.

Oleg.