Re: PROBLEM: Probabilistic segfault on AMD hardware with INVLPGB

[Rik van Riel]

On Tue, 2026-07-07 at 13:18 +0100, Matt Fleming wrote:
> Hi Rik and Henrik,
> 
> I've got a small C reproducer that triggers this within the first
> round
> on Cloudflare's AMD Turin machines:
> 
>   https://gist.github.com/mfleming/ca26ad3f8d65a12d23d62fb176480fc1
> 
> Build:
> 
>   gcc -O2 -Wall -Wextra -pthread -static -o repro-invlpgb repro-
> invlpgb.c
> 
> Run:
> 
>   ./repro-invlpgb --batch --rounds 20 --jobs 32 -d 5 -w 8 -m 2 -s 512
> -q
> 
Never mind my earlier email.

After poking at it for a few hours, I have reproduced
the issue here.

I'll try to figure out what's happening, to see how
we can fix it.

-- 
All Rights Reversed.