Re: [PATCH v2 3/5] x86/mm: check exec permissions on fault

[Dave Hansen]

On 10/25/21 9:19 AM, Nadav Amit wrote:
> That was my first version, but I was concerned that perhaps there is
> some strange scenario in which both X86_PF_WRITE and X86_PF_INSN can
> be set. That is the reason that Peter asked you whether this is
> something that might happen.
> 
> If you confirm they cannot be both set, I would the version you just
> mentioned.

I'm pretty sure they can't be set together on any sane hardware.  A
bonkers hypervisor or CPU could do it of course, but they'd be crazy.

BTW, feel free to add a WARN_ON_ONCE() if WRITE and INSN are both set.
That would be a nice place to talk about the assumption.