Re: [PATCH v3 2/4] x86/traps: Print non-canonical address on #GP

From: Ingo Molnar
Date: Wed Nov 20 2019 - 09:05:40 EST



* Jann Horn <jannh@xxxxxxxxxx> wrote:

> On Wed, Nov 20, 2019 at 2:16 PM Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> > * Jann Horn <jannh@xxxxxxxxxx> wrote:
> >
> > > On Wed, Nov 20, 2019 at 12:24 PM Borislav Petkov <bp@xxxxxxxxx> wrote:
> > > > On Wed, Nov 20, 2019 at 12:18:59PM +0100, Ingo Molnar wrote:
> > > > > How was this maximum string length of '90' derived? In what way will
> > > > > that have to change if someone changes the message?
> > > >
> > > > That was me counting the string length in a dirty patch in a previous
> > > > thread. We probably should say why we decided for a certain length and
> > > > maybe have a define for it.
> > >
> > > Do you think something like this would be better?
> > >
> > > char desc[sizeof(GPFSTR) + 50 + 2*sizeof(unsigned long) + 1] = GPFSTR;
> >
> > I'd much prefer this for, because it's a big honking warning for people
> > to not just assume things but double check the limits.
>
> Sorry, I can't parse the start of this sentence. I _think_ you're
> saying you want me to make the change to "char desc[sizeof(GPFSTR) +
> 50 + 2*sizeof(unsigned long) + 1]"?

Yeah, correct. There was an extra 'for' in my first sentence:

> > I'd much prefer this, because it's a big honking warning for people
> > to not just assume things but double check the limits.

Thanks,

Ingo