Re: [PATCH] x86/alternatives: Disable KASAN on text_poke_early() in apply_alternatives()

Kirill A. Shutemov
2023-10-10T10:30:41Z

On Tue, Oct 10, 2023 at 12:16:21PM +0200, Peter Zijlstra wrote:
> On Tue, Oct 10, 2023 at 12:10:56PM +0200, Peter Zijlstra wrote:
>
> > That said, I don't particularly like the patch, I think it should, at
> > the veyr least, cover all of apply_alternatives, not just
> > text_poke_early().
>
> kasan_arch_is_ready() is another option, x86 doesn't currently define
> that, but that would allow us to shut kasan down harder around patching.
> Not sure if it's worth the trouble though.

IIUC, it was intended to delay KASAN usage until it is ready. KASAN is
functional well before apply_alternatives() and making
kasan_arch_is_ready() temporary false for patching feels like abuse of the
hook.

--
Kiryl Shutsemau / Kirill A. Shutemov