Re: [PATCH bpf-next v4 0/3] bpf, x86: Support fetching AND/OR/XOR atomics in arena

[Tejun Heo]

Hello, Puranjay.

On Wed, Oct 14, 2026 at 05:50:10AM -0700, Puranjay Mohan wrote:
> A fetching AND/OR/XOR against arena memory is rejected on x86-64:
>
>   BPF_ATOMIC stores into R1 arena is not allowed

- 1/3: A fetching atomic through a number now fails to load with an
  empty verifier log, where it used to get the message above. That
  seems problematic. Can that case keep an error message?
- 3/3: sched_ext/for-7.4 already synced a cid.bpf.h from scx which
  probes for the fetching atomics and keeps the CAS loop as the
  old-kernel fallback, so this conflicts with it. I'll pull
  bpf/for-next into sched_ext/for-7.4 and we can do the modifications
  on top.

For 1/3 and 2/3,

Acked-by: Tejun Heo <tj@xxxxxxxxxx>

Thanks.

-- 
tejun