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From: sashiko-bot@kernel.org
To: "Jiri Olsa" <jolsa@kernel.org>
Cc: bpf@vger.kernel.org
Subject: Re: [PATCHv7 bpf-next 19/29] libbpf: Add btf_type_is_traceable_func function
Date: Wed, 03 Jun 2026 11:36:16 +0000	[thread overview]
Message-ID: <20260603113617.49FA41F00893@smtp.kernel.org> (raw)
In-Reply-To: <20260603110554.29590-20-jolsa@kernel.org>

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] btf_get_type_size() fails to handle union types, leading to the incorrect rejection of functions with valid union arguments.
--

commit 3f5d4e8440eaf929ad94e8774deb7fce495d30c8
Author: Jiri Olsa <jolsa@kernel.org>

libbpf: Add btf_type_is_traceable_func function

This commit adds the btf_type_is_traceable_func function to libbpf to
perform the same checks as the kernel's btf_distill_func_proto, preventing
attachment on unsupported functions. It exports this function via
libbpf_internal.h for use in benchmark tests.

> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index ab2071fdd3e8b..c659865ec2def 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c

[ ... ]

> +static int btf_get_type_size(const struct btf *btf, __u32 type_id,
> +			     const struct btf_type **ret_type)
> +{
> +	const struct btf_type *t;
> +	int i;
> +
> +	*ret_type = btf__type_by_id(btf, 0);
> +	if (!type_id)
> +		return 0;
> +	t = btf__type_by_id(btf, type_id);
> +	for (i = 0; i < MAX_RESOLVE_DEPTH && t && btf_type_is_modifier(t); i++)
> +		t = btf__type_by_id(btf, t->type);
> +	if (!t || i == MAX_RESOLVE_DEPTH)
> +		return -EINVAL;
> +	*ret_type = t;
> +	if (btf_is_ptr(t))
> +		return btf__pointer_size(btf);
> +	if (btf_is_int(t) || btf_is_any_enum(t) || btf_is_struct(t))
> +		return t->size;

[Severity: Medium]
Will this return -EINVAL for union types?

Unlike the kernel where btf_type_is_struct() covers both structs and unions,
libbpf's btf_is_struct() strictly checks for BTF_KIND_STRUCT. Because
btf_is_union(t) is missing from this condition, union types fall through and
return -EINVAL.

> +	return -EINVAL;
> +}
> +
> +bool btf_type_is_traceable_func(const struct btf *btf, const struct btf_type *t)
> +{

[ ... ]

> +	for (i = 0; i < nargs; i++) {
> +		/* No support for variable args. */
> +		if (i == nargs - 1 && args[i].type == 0)
> +			return false;
> +		ret = btf_get_type_size(btf, args[i].type, &t);
> +		/* No support of struct argument size greater than 16 bytes. */
> +		if (ret < 0 || ret > 16)

Because of the behavior above, will this regression incorrectly reject any
valid union arguments up to 16 bytes since btf_get_type_size() will return a
negative value? Should btf_get_type_size() check btf_is_union() to match the
kernel's actual tracing attachment rules?

> +			return false;
> +		/* No support for void argument. */
> +		if (ret == 0)
> +			return false;
> +	}
> +
> +	return true;
> +}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260603110554.29590-20-jolsa@kernel.org?part=1

  reply	other threads:[~2026-06-03 11:36 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-03 11:05 [PATCHv7 bpf-next 00/29] bpf: tracing_multi link Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 01/29] ftrace: Add ftrace_hash_count function Jiri Olsa
2026-06-03 11:26   ` sashiko-bot
2026-06-04  7:59     ` Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 02/29] ftrace: Add ftrace_hash_remove function Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 03/29] ftrace: Add add_ftrace_hash_entry function Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 04/29] bpf: Use mutex lock pool for bpf trampolines Jiri Olsa
2026-06-03 11:28   ` sashiko-bot
2026-06-04  7:59     ` Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 05/29] bpf: Add struct bpf_trampoline_ops object Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 06/29] bpf: Move trampoline image setup into bpf_trampoline_ops callbacks Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 07/29] bpf: Add bpf_trampoline_add/remove_prog functions Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 08/29] bpf: Add struct bpf_tramp_node object Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 09/29] bpf: Factor fsession link to use struct bpf_tramp_node Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 10/29] bpf: Add multi tracing attach types Jiri Olsa
2026-06-03 11:37   ` sashiko-bot
2026-06-04  8:00     ` Jiri Olsa
2026-06-03 11:52   ` bot+bpf-ci
2026-06-03 11:05 ` [PATCHv7 bpf-next 11/29] bpf: Move sleepable verification code to btf_id_allow_sleepable Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 12/29] bpf: Add bpf_trampoline_multi_attach/detach functions Jiri Olsa
2026-06-03 11:52   ` bot+bpf-ci
2026-06-03 11:05 ` [PATCHv7 bpf-next 13/29] bpf: Add support for tracing multi link Jiri Olsa
2026-06-03 11:41   ` sashiko-bot
2026-06-04  8:00     ` Jiri Olsa
2026-06-03 11:52   ` bot+bpf-ci
2026-06-04  8:00     ` Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 14/29] bpf: Add support for tracing_multi link cookies Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 15/29] bpf: Add support for tracing_multi link session Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 16/29] bpf: Add support for tracing_multi link fdinfo Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 17/29] libbpf: Add bpf_object_cleanup_btf function Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 18/29] libbpf: Add bpf_link_create support for tracing_multi link Jiri Olsa
2026-06-03 11:34   ` sashiko-bot
2026-06-04  7:59     ` Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 19/29] libbpf: Add btf_type_is_traceable_func function Jiri Olsa
2026-06-03 11:36   ` sashiko-bot [this message]
2026-06-04  7:59     ` Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 20/29] libbpf: Add support to create tracing multi link Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 21/29] selftests/bpf: Add tracing multi skel/pattern/ids attach tests Jiri Olsa
2026-06-03 13:40   ` sashiko-bot
2026-06-04  8:00     ` Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 22/29] selftests/bpf: Add tracing multi skel/pattern/ids module " Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 23/29] selftests/bpf: Add tracing multi intersect tests Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 24/29] selftests/bpf: Add tracing multi cookies test Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 25/29] selftests/bpf: Add tracing multi session test Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 26/29] selftests/bpf: Add tracing multi attach fails test Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 27/29] selftests/bpf: Add tracing multi verifier " Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 28/29] selftests/bpf: Add tracing multi attach benchmark test Jiri Olsa
2026-06-03 11:05 ` [PATCHv7 bpf-next 29/29] selftests/bpf: Add tracing multi attach rollback tests Jiri Olsa

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