linux-kernel - Re: [PATCH v2] x86/fault: Decode and print #PF oops in human readable form

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Message-ID: <CAHk-=wizzTem4B3muo+DV5JqPBD0n1JJ8-NDjyY1fn-N4WYHCg@mail.gmail.com>
Date:   Fri, 7 Dec 2018 14:14:22 -0800
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     sean.j.christopherson@...el.com
Cc:     dave.hansen@...ux.intel.com, Andrew Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, bp@...en8.de,
        "the arch/x86 maintainers" <x86@...nel.org>,
        Peter Anvin <hpa@...or.com>,
        Linux List Kernel Mailing <linux-kernel@...r.kernel.org>,
        Rik van Riel <riel@...riel.com>, yu-cheng.yu@...el.com,
        Ingo Molnar <mingo@...nel.org>
Subject: Re: [PATCH v2] x86/fault: Decode and print #PF oops in human readable form

On Fri, Dec 7, 2018 at 2:06 PM Sean Christopherson
<sean.j.christopherson@...el.com> wrote:
>
> Looking at it again, my own personal preference would be to swap the order
> of the #PF lines.

Yeah, probably.

Also:

> [  160.246820] BUG: unable to handle kernel paging request at ffffbeef00000000
> [  160.247517] #PF: supervisor-privileged instruction fetch from kernel code
> [  160.248085] #PF: error_code(0x0010) - not-present page

With this form, I think the "kernel" in the first line is actually
misleading. Yes, it's a #PF for the kernel, but then the "kernel" on
the second line talks about what mode we were in when it happened, so
we have two different meanings of "kernel" on two adjacent lines.

So maybe  that "BUG: unable to handle kernel paging request" message
should be something like

  "BUG: unable to handle page fault for address ffffbeef00000000"

instead? Does that make sense to people?

Anyway, enough bike-shedding from me, I'll just shut up about this,
since I don't really care all that deeply, and I wasn't really the
target audience anyway. Sorry for the noise, and I'll leave the
decision to the people who actually wanted this.

                  Linus

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