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

[Andy Lutomirski]

On Fri, Dec 7, 2018 at 2:14 PM Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> On Fri, Dec 7, 2018 at 2:06 PM Sean Christopherson
> <sean.j.christopherson@xxxxxxxxx> 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.

I'm okay with this variant.  I have a slight preference for:

#PF: supervisor-privileged instruction fetch from kernel code
#PF error_code: 0x0010 [READ]

Which is what we'd get from Sean's patch plus my patch here:

https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/commit/?h=x86/mm&id=ccfb1941f90153818c07fb1a7dc22121a970d252

Sean, what do you think?

> 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?

Yes please.