Re: [PATCH] x86/mm: Define the zapped-entry checks only with CONFIG_DEBUG_VM

[Kiryl Shutsemau]

On Tue, Nov 03, 2026 at 03:50:04PM +0000, Edgecombe, Rick P wrote:
> On Tue, 2026-11-03 at 10:13 +0000, Kiryl Shutsemau wrote:
> > On Mon, Nov 02, 2026 at 01:12:47PM -0800, Dave Hansen wrote:
> > > Or, heck, I'm not that attached to these checks. Let's just kill them.
> > 
> > Works for me. x86 is the only architecture with them, although arm64 and
> > riscv have shadow stacks too, and the x86 helpers already keep
> > Write=0,Dirty=1 out of other VMAs. Patch below, without the Fixes: tag.
> > 
> > Rick, any objection?
> 
> Eh, I guess I'm lukewarm on it. These checks only catch the case at zap time, so
> it's not a huge protection that is being pulled out. I thought they were useful.
> At the same time, they have never triggered.

Yeah, I have not find any reports.

So, we can claim that the check served its purpose to stabilize shadow
stack and can be retired now :P

I will post the patch separately.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov