Re: [patch 0/2] x86/alternatives: Prevent crash in NOP optimizer

[Peter Zijlstra]

On Thu, Dec 07, 2023 at 08:49:22PM +0100, Thomas Gleixner wrote:
> The following series addresses the regression report from Paul on behalf of
> the yocto project. It turns out that the recent changes to alternatives
> opened a race window where interrupts are enabled and NOPs are optimized in
> place. An interrupt hitting into the modification will observe inconsistent
> text and crash and burn.
> 
> A 32bit QEMU crashes w/o these fixes reliably within about 50 boot
> attempts. With the fix applied it survived close to 600 attempts by
> now.
> 
> Thanks to Paul for providing all the information!

Urgh and D'0h.

Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>