From: Ihor Solodrai <ihor.solodrai@linux.dev>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Eduard Zingerman <eddyz87@gmail.com>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Quentin Monnet <qmo@kernel.org>
Cc: bpf@vger.kernel.org, Alan Maguire <alan.maguire@oracle.com>,
Cupertino Miranda <cupertino.miranda@oracle.com>,
David Faust <david.faust@oracle.com>,
Ian Rogers <irogers@google.com>,
"Jose E . Marchesi" <jose.marchesi@oracle.com>,
Vineet Gupta <vineet.gupta@linux.dev>,
Yonghong Song <yonghong.song@linux.dev>
Subject: Re: [PATCH bpf-next v1 5/8] bpftool: Emit __bpf_core_pso on verifier-rewritten context types
Date: Thu, 15 Oct 2026 22:49:01 -0700 [thread overview]
Message-ID: <b0bb3596-35a9-471b-a666-d7a638d00e5d@linux.dev> (raw)
In-Reply-To: <DM5VEJ802JZJ.2Y2NI0GZNVXMD@gmail.com>
On 2026-10-15 6:27 p.m., Alexei Starovoitov wrote:
> On Thu, Oct 15, 2026 at 05:00 PM Ihor Solodrai <ihor.solodrai@linux.dev> wrote:
>> Clang 18 through 23 crash on __builtin_preserve_field_info over a PSO
>> record, including bpf_core_field_*() and the CO-RE bitfield helpers.
>> -D__bpf_core_pso= can disable PSO for affected programs.
>
> ouch. anyone working on fixing llvm ?
I have a vibe coded fix, planned to review it and send a PR.
> hopefully people don't do
> bpf_core_field_exists(skb->tstamp_type)
> when skb is __sk_buff.
>
> since nobody will know about -D__bpf_core_pso= workaround.
When PSO lands, people might run into this as soon as they use new
bpftool to generate vmlinux.h, and the failure is very loud.
Since the bug is quite old, I am not sure it's feasible to fix it
everywhere. Probably best we can do is advertise the workaround.
>
> Name is also not great.
> "bpf_context" ?
Yeah, the __bpf_core_<foo> might not be the best name.
I like btf_relocatable for PAI, should this be btf_unrelocatable?..
In any case this is bikeshedding, the macro is local to vmlinux.h,
not a big deal.
next prev parent reply other threads:[~2026-10-16 5:49 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-16 0:00 [PATCH bpf-next v1 0/8] bpftool: Per-record CO-RE attributes in the C dump Ihor Solodrai
2026-10-16 0:00 ` [PATCH bpf-next v1 1/8] bpftool: Dump C from a detached BTF copy Ihor Solodrai
2026-10-16 1:18 ` Alexei Starovoitov
2026-10-16 9:44 ` Alan Maguire
2026-10-16 9:25 ` Alan Maguire
2026-10-16 0:00 ` [PATCH bpf-next v1 2/8] selftests/bpf: Cover unknown BTF header-extension bytes in btf dump Ihor Solodrai
2026-10-16 0:00 ` [PATCH bpf-next v1 3/8] bpftool: Apply __bpf_core_pai per record on BTF dump Ihor Solodrai
2026-10-16 0:39 ` bot+bpf-ci
2026-10-16 1:17 ` Alexei Starovoitov
2026-10-16 0:00 ` [PATCH bpf-next v1 4/8] bpftool: Skip __bpf_core_pai on verifier-rewritten context types Ihor Solodrai
2026-10-16 0:00 ` [PATCH bpf-next v1 5/8] bpftool: Emit __bpf_core_pso " Ihor Solodrai
2026-10-16 1:27 ` Alexei Starovoitov
2026-10-16 5:49 ` Ihor Solodrai [this message]
2026-10-16 0:00 ` [PATCH bpf-next v1 6/8] selftests/bpf: Cover record attributes in bpftool BTF dumps Ihor Solodrai
2026-10-16 0:00 ` [PATCH bpf-next v1 7/8] selftests/bpf: Cover context and socket accesses through vmlinux.h Ihor Solodrai
2026-10-16 0:00 ` [PATCH bpf-next v1 8/8] bpftool: Document __bpf_core_pai and __bpf_core_pso Ihor Solodrai
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