From: Eduard Zingerman <eddyz87@gmail.com>
To: bot+bpf-ci@kernel.org, bpf@vger.kernel.org, ast@kernel.org,
andrii@kernel.org
Cc: daniel@iogearbox.net, martin.lau@linux.dev, kernel-team@fb.com,
yonghong.song@linux.dev, memxor@gmail.com, npc@anthropic.com,
martin.lau@kernel.org, mason@kernel.org,
ihor.solodrai@linux.dev
Subject: Re: [PATCH bpf 2/3] bpf: update disasm.c to print BPF_PROBE_ATOMIC as atomics
Date: Thu, 03 Sep 2026 12:38:28 -0700 [thread overview]
Message-ID: <2f40ba155a98bd357ff5c1182308ce10a425811a.camel@gmail.com> (raw)
In-Reply-To: <2ddb3272d086e995630c56ed4c2cc2cdec75debd5fff9c10cb0bfe8c0fe664ef@mail.kernel.org>
On Thu, 2026-09-03 at 18:11 +0000, bot+bpf-ci@kernel.org wrote:
> > bpf: update disasm.c to print BPF_PROBE_ATOMIC as atomics
> >
> > bpf_convert_ctx_accesses() rewrites an atomic on an arena pointer from
> > BPF_STX | BPF_ATOMIC to BPF_STX | BPF_PROBE_ATOMIC, this patch adjusts
> > print_bpf_insn() to print such instructions as regular atomics with a
> > 'probe_' prefix (instead of printing them as BUG_XX).
>
> The changelog says the instructions are printed "as regular atomics with
> a 'probe_' prefix", but looking at the implementation:
>
> const char *probe_pfx = BPF_MODE(insn->code) == BPF_PROBE_ATOMIC ? "probe " : "";
> ...
> verbose(cbs->private_data, "(%02x) %sr0 = atomic%s_cmpxchg((%s *)(r%d %+d), r0, r%d)",
> insn->code, probe_pfx, ...);
>
> the code emits a separate word "probe " (trailing space, no underscore)
> at the start of the rendered instruction, producing output like:
>
> probe r0 = atomic_cmpxchg((u32 *)(r1 +0), r0, r2)
>
> rather than:
>
> r0 = probe_atomic_cmpxchg(...)
>
> as the message suggests. For the fetch/cmpxchg/xchg/load_acquire/
> store_release forms, this also detaches the qualifier from the operation
> it qualifies (e.g. "probe r%d = atomic..._fetch_...", reading as if
> "probe" modified the destination register).
>
> Should the changelog describe the emitted "probe " prefix, or should the
> prefix be attached to the operation name (probe_atomic_cmpxchg,
> probe_load_acquire, etc.) to match the message?
Yes, I should have updated the log. The intent is to print:
(hex) probe ...something-something...
will respin v2, waiting for sashiko.
next prev parent reply other threads:[~2026-09-03 19:38 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-03 17:15 [PATCH bpf 1/3] bpf: zero extend the result of an arena 32-bit cmpxchg Eduard Zingerman
2026-09-03 17:15 ` [PATCH bpf 2/3] bpf: update disasm.c to print BPF_PROBE_ATOMIC as atomics Eduard Zingerman
2026-09-03 18:11 ` bot+bpf-ci
2026-09-03 19:38 ` Eduard Zingerman [this message]
2026-09-03 17:15 ` [PATCH bpf 3/3] selftests/bpf: check zero extension of an arena 32-bit cmpxchg Eduard Zingerman
2026-09-04 2:00 ` [PATCH bpf 1/3] bpf: zero extend the result " patchwork-bot+netdevbpf
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