From: Jiri Olsa <olsajiri@gmail.com>
To: bot+bpf-ci@kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
kafai@fb.com, eddyz87@gmail.com, songliubraving@fb.com,
yhs@fb.com, menglong8.dong@gmail.com, rostedt@kernel.org,
martin.lau@kernel.org, yonghong.song@linux.dev, clm@meta.com,
ihor.solodrai@linux.dev
Subject: Re: [PATCHv2 bpf-next 06/23] bpf: Add multi tracing attach types
Date: Thu, 5 Mar 2026 15:02:31 +0100 [thread overview]
Message-ID: <aamM95ydg4RFY-MP@krava> (raw)
In-Reply-To: <90246a2d7a691e7374b18d699e0778f10b750b85fd0739d485c96960925a822b@mail.kernel.org>
On Wed, Mar 04, 2026 at 11:02:33PM +0000, bot+bpf-ci@kernel.org wrote:
> > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> > index d92cf2821657..832a87da5a86 100644
> > --- a/kernel/bpf/verifier.c
> > +++ b/kernel/bpf/verifier.c
>
> [ ... ]
>
> > @@ -25173,6 +25181,8 @@ int bpf_check_attach_target(struct bpf_verifier_log *log,
> > case BPF_TRACE_FENTRY:
> > case BPF_TRACE_FEXIT:
> > case BPF_TRACE_FSESSION:
> > + case BPF_TRACE_FENTRY_MULTI:
> > + case BPF_TRACE_FEXIT_MULTI:
>
> The new multi types are added to this switch, but earlier in the same
> function bpf_check_attach_target() there is a check that prevents
> BPF_PROG_TYPE_EXT from targeting fentry/fexit/fsession programs:
>
> kernel/bpf/verifier.c:bpf_check_attach_target() {
> ...
> if (tgt_prog->type == BPF_PROG_TYPE_TRACING &&
> prog_extension &&
> (tgt_prog->expected_attach_type == BPF_TRACE_FENTRY ||
> tgt_prog->expected_attach_type == BPF_TRACE_FEXIT ||
> tgt_prog->expected_attach_type == BPF_TRACE_FSESSION)) {
> bpf_log(log, "Cannot extend fentry/fexit/fsession\n");
> return -EINVAL;
> }
> ...
> }
>
> Should BPF_TRACE_FENTRY_MULTI and BPF_TRACE_FEXIT_MULTI be included
> in that check as well? The comment above it explains that extending
> fentry/fexit programs is blocked to prevent
> fentry->extension->fentry->extension call chains. Multi programs map
> to BPF_TRAMP_FENTRY/BPF_TRAMP_FEXIT in bpf_attach_type_to_tramp(),
> so the same concern would apply.
but multi programs would never have tgt_prog/prog->aux->dst_prog set,
and that check above is under 'if (tgt_prog) {' check, so I think we
are ok, but I will double check, thnx
jirka
>
> > @@ -25202,7 +25212,17 @@ int bpf_check_attach_target(struct bpf_verifier_log *log,
>
> [ ... ]
>
>
> ---
> AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
> See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
>
> CI run summary: https://github.com/kernel-patches/bpf/actions/runs/22692622038
next prev parent reply other threads:[~2026-03-05 14:02 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-04 22:21 [PATCHv2 bpf-next 00/23] bpf: tracing_multi link Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 01/23] ftrace: Add ftrace_hash_count function Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 02/23] bpf: Use mutex lock pool for bpf trampolines Jiri Olsa
2026-03-04 23:02 ` bot+bpf-ci
2026-03-05 14:01 ` Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 03/23] bpf: Add struct bpf_trampoline_ops object Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 04/23] bpf: Add struct bpf_tramp_node object Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 05/23] bpf: Factor fsession link to use struct bpf_tramp_node Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 06/23] bpf: Add multi tracing attach types Jiri Olsa
2026-03-04 23:02 ` bot+bpf-ci
2026-03-05 14:02 ` Jiri Olsa [this message]
2026-03-04 22:21 ` [PATCHv2 bpf-next 07/23] bpf: Move sleepable verification code to btf_id_allow_sleepable Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 08/23] bpf: Add bpf_trampoline_multi_attach/detach functions Jiri Olsa
2026-03-04 23:02 ` bot+bpf-ci
2026-03-05 14:02 ` Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 09/23] bpf: Add support for tracing multi link Jiri Olsa
2026-03-04 23:02 ` bot+bpf-ci
2026-03-05 14:02 ` Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 10/23] bpf: Add support for tracing_multi link cookies Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 11/23] bpf: Add support for tracing_multi link session Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 12/23] bpf: Add support for tracing_multi link fdinfo Jiri Olsa
2026-03-04 23:02 ` bot+bpf-ci
2026-03-05 14:01 ` Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 13/23] libbpf: Add bpf_object_cleanup_btf function Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 14/23] libbpf: Add bpf_link_create support for tracing_multi link Jiri Olsa
2026-03-04 23:02 ` bot+bpf-ci
2026-03-05 14:01 ` Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 15/23] libbpf: Add support to create tracing multi link Jiri Olsa
2026-03-04 23:02 ` bot+bpf-ci
2026-03-05 14:02 ` Jiri Olsa
2026-03-05 6:59 ` Leon Hwang
2026-03-05 14:02 ` Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 16/23] selftests/bpf: Add tracing multi skel/pattern/ids attach tests Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 17/23] selftests/bpf: Add tracing multi skel/pattern/ids module " Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 18/23] selftests/bpf: Add tracing multi intersect tests Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 19/23] selftests/bpf: Add tracing multi cookies test Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 20/23] selftests/bpf: Add tracing multi session test Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 21/23] selftests/bpf: Add tracing multi attach fails test Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 22/23] selftests/bpf: Add tracing multi attach benchmark test Jiri Olsa
2026-03-05 7:30 ` Leon Hwang
2026-03-05 14:01 ` Jiri Olsa
2026-03-04 22:21 ` [PATCHv2 bpf-next 23/23] selftests/bpf: Add tracing multi rollback tests Jiri Olsa
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