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From:   Andy Lutomirski <luto@amacapital.net>
Date:   Wed, 11 Dec 2019 10:17:25 -0800
Message-ID: <CALCETrXuJMBawUy3DTQfE4qLb822d9491er9-hd971BtBsPFNw@mail.gmail.com>
Subject: Re: [PATCH v6 2/4] x86/traps: Print address on #GP
To:     Borislav Petkov <bp@alien8.de>
Cc:     Jann Horn <jannh@google.com>, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, X86 ML <x86@kernel.org>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        kasan-dev <kasan-dev@googlegroups.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Andrey Konovalov <andreyknvl@google.com>,
        Andy Lutomirski <luto@kernel.org>,
        Sean Christopherson <sean.j.christopherson@intel.com>
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On Wed, Dec 11, 2019 at 9:29 AM Borislav Petkov <bp@alien8.de> wrote:
>
> On Wed, Dec 11, 2019 at 09:22:30AM -0800, Andy Lutomirski wrote:
> > Could we spare a few extra bytes to make this more readable?  I can nev=
er keep track of which number is the oops count, which is the cpu, and whic=
h is the error code.  How about:
> >
> > OOPS 1: general protection blah blah blah (CPU 0)
> >
> > and put in the next couple lines =E2=80=9C#GP(0)=E2=80=9D.
>
> Well, right now it is:
>
> [    2.470492] general protection fault, probably for non-canonical addre=
ss 0xdfff000000000001: 0000 [#1] PREEMPT SMP
> [    2.471615] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.5.0-rc1+ #6
>
> and the CPU is on the second line, the error code is before the number -
> [#1] - in that case.
>
> If we pull the number in front, we can do:
>
> [    2.470492] [#1] general protection fault, probably for non-canonical =
address 0xdfff000000000001: 0000 PREEMPT SMP
> [    2.471615] [#1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.5.0-rc1+ =
#6
>
> and this way you know that the error code is there, after the first
> line's description.

Hmm, I like that.

>
> I guess we can do:
>
> [    2.470492] [#1] general protection fault, probably for non-canonical =
address 0xdfff000000000001 Error Code: 0000 PREEMPT SMP
>
> to make it even more explicit...

I like this too.

>
> --
> Regards/Gruss,
>     Boris.
>
> https://people.kernel.org/tglx/notes-about-netiquette


--=20
Andy Lutomirski
AMA Capital Management, LLC