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: [PATCH bpf-next 08/17] bpf: Add support for tracing multi link
Date: Sun, 22 Feb 2026 15:35:07 +0100 [thread overview]
Message-ID: <aZsUG16KRLWzpQO-@krava> (raw)
In-Reply-To: <e41633c6d6d32fabb08ecc4ae8432a45afaa72aa61756601f4cdb9aebd039f86@mail.kernel.org>
On Fri, Feb 20, 2026 at 10:57:58AM +0000, bot+bpf-ci@kernel.org wrote:
> > diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
> > --- a/include/linux/bpf_types.h
> > +++ b/include/linux/bpf_types.h
>
> [ ... ]
>
> > +BPF_LINK_TYPE(BPF_LINK_TYPE_TRACING_MULTI, tracing)
>
> The existing BPF_LINK_TYPE_TRACING also uses "tracing" as its name
> argument:
>
> BPF_LINK_TYPE(BPF_LINK_TYPE_TRACING, tracing)
>
> This means bpf_link_type_strs[] will contain "tracing" for both
> BPF_LINK_TYPE_TRACING and BPF_LINK_TYPE_TRACING_MULTI, making them
> indistinguishable in fdinfo output via bpf_link_show_fdinfo().
>
> The libbpf side correctly uses "tracing_multi":
>
> [BPF_LINK_TYPE_TRACING_MULTI] = "tracing_multi",
>
> Should this be BPF_LINK_TYPE(BPF_LINK_TYPE_TRACING_MULTI, tracing_multi)
> to match?
it should, fixed
>
> > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> > --- a/kernel/trace/bpf_trace.c
> > +++ b/kernel/trace/bpf_trace.c
>
> [ ... ]
>
> > +int bpf_tracing_multi_attach(struct bpf_prog *prog, const union bpf_attr *attr)
> > +{
>
> [ ... ]
>
> > + ids = kvmalloc_array(cnt, sizeof(*ids), GFP_KERNEL);
>
> [ ... ]
>
> > + link = kzalloc(struct_size(link, nodes, cnt), GFP_KERNEL);
> ^^^^^^
>
> The ids array above uses kvmalloc_array() to handle large allocations,
> but the link struct uses kzalloc(). With MAX_TRACING_MULTI_CNT at 1M
> and each bpf_tracing_multi_node being roughly 40 bytes,
> struct_size() can request up to ~40MB of contiguous memory. kzalloc()
> is limited to KMALLOC_MAX_SIZE (~4MB on x86_64), so this will fail
> for cnt values above roughly 100K.
>
> Would kvzalloc() work here instead? bpf_tracing_multi_link_dealloc()
> would need to use kvfree() accordingly:
>
> > +static void bpf_tracing_multi_link_dealloc(struct bpf_link *link)
> > +{
> > + struct bpf_tracing_multi_link *tr_link =
> > + container_of(link, struct bpf_tracing_multi_link, link);
> > +
> > + kfree(tr_link);
yes, makes sense, will fix, thnx
jirka
next prev parent reply other threads:[~2026-02-22 14:35 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-20 10:06 [PATCH bpf-next 00/17] bpf: tracing_multi link Jiri Olsa
2026-02-20 10:06 ` [PATCH bpf-next 01/17] ftrace: Add ftrace_hash_count function Jiri Olsa
2026-02-20 10:06 ` [PATCH bpf-next 02/17] bpf: Use mutex lock pool for bpf trampolines Jiri Olsa
2026-02-20 10:57 ` bot+bpf-ci
2026-02-22 14:33 ` Jiri Olsa
2026-02-20 19:58 ` Alexei Starovoitov
2026-02-22 14:34 ` Jiri Olsa
2026-02-23 19:35 ` Alexei Starovoitov
2026-02-24 12:27 ` Jiri Olsa
2026-02-24 17:13 ` Alexei Starovoitov
2026-02-20 10:06 ` [PATCH bpf-next 03/17] bpf: Add struct bpf_trampoline_ops object Jiri Olsa
2026-02-20 10:06 ` [PATCH bpf-next 04/17] bpf: Add struct bpf_tramp_node object Jiri Olsa
2026-02-20 10:58 ` bot+bpf-ci
2026-02-22 14:34 ` Jiri Olsa
2026-02-20 19:52 ` kernel test robot
2026-02-20 21:05 ` kernel test robot
2026-02-21 3:00 ` kernel test robot
2026-02-20 10:06 ` [PATCH bpf-next 05/17] bpf: Factor fsession link to use struct bpf_tramp_node Jiri Olsa
2026-02-20 10:06 ` [PATCH bpf-next 06/17] bpf: Add multi tracing attach types Jiri Olsa
2026-02-20 10:06 ` [PATCH bpf-next 07/17] bpf: Add bpf_trampoline_multi_attach/detach functions Jiri Olsa
2026-02-20 10:57 ` bot+bpf-ci
2026-02-22 14:34 ` Jiri Olsa
2026-02-20 10:06 ` [PATCH bpf-next 08/17] bpf: Add support for tracing multi link Jiri Olsa
2026-02-20 10:57 ` bot+bpf-ci
2026-02-22 14:35 ` Jiri Olsa [this message]
2026-02-20 10:06 ` [PATCH bpf-next 09/17] bpf: Add support for tracing_multi link cookies Jiri Olsa
2026-02-20 10:06 ` [PATCH bpf-next 10/17] bpf: Add support for tracing_multi link session Jiri Olsa
2026-02-20 10:57 ` bot+bpf-ci
2026-02-22 14:35 ` Jiri Olsa
2026-02-20 10:06 ` [PATCH bpf-next 11/17] libbpf: Add support to create tracing multi link Jiri Olsa
2026-02-20 10:57 ` bot+bpf-ci
2026-02-22 14:36 ` Jiri Olsa
2026-02-20 10:06 ` [PATCH bpf-next 12/17] selftests/bpf: Add tracing multi skel/pattern/ids attach tests Jiri Olsa
2026-02-20 10:06 ` [PATCH bpf-next 13/17] selftests/bpf: Add tracing multi intersect tests Jiri Olsa
2026-02-20 10:06 ` [PATCH bpf-next 14/17] selftests/bpf: Add tracing multi cookies test Jiri Olsa
2026-02-20 10:06 ` [PATCH bpf-next 15/17] selftests/bpf: Add tracing multi session test Jiri Olsa
2026-02-20 10:06 ` [PATCH bpf-next 16/17] selftests/bpf: Add tracing multi attach fails test Jiri Olsa
2026-02-20 10:06 ` [PATCH bpf-next 17/17] selftests/bpf: Add tracing multi attach benchmark test Jiri Olsa
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