Re: [PATCH bpf 1/3] bpf: zero extend the result of an arena 32-bit cmpxchg

[patchwork-bot+netdevbpf@kernel.org]

Hello:

This series was applied to bpf/bpf.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Thu,  3 Sep 2026 10:15:39 -0700 you wrote:
> bpf_convert_ctx_accesses() rewrites an atomic on an arena pointer from
> BPF_STX | BPF_ATOMIC to BPF_STX | BPF_PROBE_ATOMIC, and it runs before
> bpf_opt_subreg_zext_lo32_rnd_hi32().
> 
> That pass emits an explicit zero extension for a 32-bit cmpxchg even
> when bpf_jit_needs_zext() is false. This is done because on some
> architectures 32-bit cmpxchg requires explicit zero extension for the
> dst register. E.g. on x86-64 'lock cmpxchg' does not change the %eax
> if comparison is successful, while BPF semantics declare that each
> operation on a 32-bit register zero extends it's upper half.
> 
> [...]

Here is the summary with links:
  - [bpf,1/3] bpf: zero extend the result of an arena 32-bit cmpxchg
    https://git.kernel.org/bpf/bpf/c/4814ed6406f3
  - [bpf,2/3] bpf: update disasm.c to print BPF_PROBE_ATOMIC as atomics
    https://git.kernel.org/bpf/bpf/c/1f3cd9719c40
  - [bpf,3/3] selftests/bpf: check zero extension of an arena 32-bit cmpxchg
    https://git.kernel.org/bpf/bpf/c/54ed91950363

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html