linux-kernel - Re: [RFC 6/8] x86_64/bug: Implement __WARN

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Message-ID: <CAHk-=wiYHv2duN1Aj3E5UD3zH=z6A9YpGJ1Mxj_CWL7_FRMKgw@mail.gmail.com>
Date: Mon, 2 Jun 2025 09:38:09 -0700
From: Linus Torvalds <torvalds@...uxfoundation.org>
To: Peter Zijlstra <peterz@...radead.org>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org, kees@...nel.org, 
	acarmina@...hat.com, jpoimboe@...nel.org, mark.rutland@....com
Subject: Re: [RFC 6/8] x86_64/bug: Implement __WARN_printf()

On Mon, 2 Jun 2025 at 08:50, Peter Zijlstra <peterz@...radead.org> wrote:
>
> Yes, it absolutely builds with clang. The inline asm isn't something we
> don't already do elsewhere :-) *cough* extable *cough*

Eww. I hadn't looked at that (or repressed it if I did). *Shudder*.

But looking around, I don't think any of the normal code I ever look
at actually *generate* that disgusting thing.

I had to search for it, and looked at the absolute horror it generates
in the futex code, and honestly, if I ever have to look at that
garbage, I would throw up.

And WARN_ONCE() is in stuff I *do* look at.

So no. I'm NAK'ing it just because it makes the asm look entirely unreadable.

And no, I'm not ok with only using 'objdump' and friends to look at
assembly generation. I want to be able to do

   make xyz.s

and look at code generation without throwing up.

The fact that we have this disgusting thing elsewhere in places that
I've not looked at does *not* excuse adding it to other places.

                Linus