From: Eduard Zingerman <eddyz87@gmail.com>
To: bot+bpf-ci@kernel.org, memxor@gmail.com, bpf@vger.kernel.org
Cc: npc@anthropic.com, ast@kernel.org, andrii@kernel.org,
daniel@iogearbox.net, emil@etsalapatis.com, kkd@meta.com,
kernel-team@meta.com, martin.lau@kernel.org,
yonghong.song@linux.dev, mason@kernel.org,
ihor.solodrai@linux.dev
Subject: Re: [PATCH bpf v3 4/7] bpf: Restrict CO-RE poisoning to relocatable instructions
Date: Mon, 14 Sep 2026 13:13:55 -0700 [thread overview]
Message-ID: <430c4b68e4508f61d8d4651feeb268ef7e3d5afe.camel@gmail.com> (raw)
In-Reply-To: <e5f571dcc350b1f28f4058988abe4a0b8d90efc1eeb6e83100f34a21953cbdfa@mail.kernel.org>
On Mon, 2026-09-14 at 14:15 +0000, bot+bpf-ci@kernel.org wrote:
...
> > @@ -1066,6 +1055,8 @@ int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn,
> > case BPF_ALU64:
> > if (BPF_SRC(insn->code) != BPF_K)
> > return -EINVAL;
> > + if (res->poison)
> > + goto poison;
>
> Moving the poison handling after the class/operand-form checks makes the
> silent return -EINVAL reachable for unresolved relocations. Would adding a
> pr_warn() on this path help with debugging?
>
> Before this change, relocations with res->poison set jumped to the poison
> label at the top of the function and always returned 0 without reaching
> the BPF_SRC check. Now an unresolved relocation targeting a register-source
> ALU or ALU64 instruction (BPF_MOV32_REG, BPF_MOV64_REG, or
> BPF_ALU|BPF_END|BPF_TO_BE which encodes BPF_SRC == BPF_X) fails program
> load with -EINVAL and nothing in the verifier or libbpf log explaining why.
Ok, this might be a legit nit.
Add a goto default switch branch instead of `return -EINVAL;`
in the BPF_ALU64 case?
...
next prev parent reply other threads:[~2026-09-14 20:14 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-14 13:16 [PATCH bpf v3 0/7] Misc bug fixes - part 5 Kumar Kartikeya Dwivedi
2026-09-14 13:16 ` [PATCH bpf v3 1/7] bpf: Make post-verification instruction rewrites killable Kumar Kartikeya Dwivedi
2026-09-14 14:30 ` bot+bpf-ci
2026-09-14 18:52 ` Eduard Zingerman
2026-09-14 13:16 ` [PATCH bpf v3 2/7] bpf: Preserve packet pointer class displacement in regsafe() Kumar Kartikeya Dwivedi
2026-09-14 14:30 ` bot+bpf-ci
2026-09-14 18:53 ` Eduard Zingerman
2026-09-14 13:16 ` [PATCH bpf v3 3/7] selftests/bpf: Test packet pointer class displacement pruning Kumar Kartikeya Dwivedi
2026-09-14 13:16 ` [PATCH bpf v3 4/7] bpf: Restrict CO-RE poisoning to relocatable instructions Kumar Kartikeya Dwivedi
2026-09-14 14:08 ` sashiko-bot
2026-09-14 14:15 ` bot+bpf-ci
2026-09-14 20:13 ` Eduard Zingerman [this message]
2026-09-14 19:54 ` Andrii Nakryiko
2026-09-14 20:21 ` Alexei Starovoitov
2026-09-14 20:42 ` Kumar Kartikeya Dwivedi
2026-09-14 21:02 ` Andrii Nakryiko
2026-09-14 20:09 ` Eduard Zingerman
2026-09-14 13:16 ` [PATCH bpf v3 5/7] selftests/bpf: Test CO-RE instruction poisoning restrictions Kumar Kartikeya Dwivedi
2026-09-14 14:30 ` bot+bpf-ci
2026-09-14 20:46 ` Eduard Zingerman
2026-09-14 13:16 ` [PATCH bpf v3 6/7] bpf: Assign lock identity to callback map values Kumar Kartikeya Dwivedi
2026-09-14 14:30 ` bot+bpf-ci
2026-09-14 19:33 ` Eduard Zingerman
2026-09-14 13:16 ` [PATCH bpf v3 7/7] selftests/bpf: Check callback map value lock identity Kumar Kartikeya Dwivedi
2026-09-14 14:45 ` bot+bpf-ci
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=430c4b68e4508f61d8d4651feeb268ef7e3d5afe.camel@gmail.com \
--to=eddyz87@gmail.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bot+bpf-ci@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=emil@etsalapatis.com \
--cc=ihor.solodrai@linux.dev \
--cc=kernel-team@meta.com \
--cc=kkd@meta.com \
--cc=martin.lau@kernel.org \
--cc=mason@kernel.org \
--cc=memxor@gmail.com \
--cc=npc@anthropic.com \
--cc=yonghong.song@linux.dev \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox