From: sashiko-bot@kernel.org
To: "Jay Wang" <wanjay@amazon.com>
Cc: bpf@vger.kernel.org, linux-modules@vger.kernel.org
Subject: Re: [PATCH bpf-next v2 9/9] kbuild, bpf: allow building the vmlinux BTF as a module
Date: Fri, 25 Sep 2026 21:33:05 +0000 [thread overview]
Message-ID: <20260925213305.A7C371F000FF@smtp.kernel.org> (raw)
In-Reply-To: <20260925211314.5118-10-wanjay@amazon.com>
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] kconfig: turning DEBUG_INFO_BTF into tristate silently disables dependent bool features
--
commit f23aaa487601db0500af9e21873fa5fc4f1af7b5
Author: Jay Wang <wanjay@amazon.com>
kbuild, bpf: allow building the vmlinux BTF as a module
This commit makes CONFIG_DEBUG_INFO_BTF a tristate. It allows the vmlinux
BTF to be built as a module (btf_vmlinux) that is loaded on demand, saving
memory when it is not needed.
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 134b15a44625e..418025c5e6577 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -396,7 +396,7 @@ config DEBUG_INFO_SPLIT
> Incompatible with older versions of ccache.
>
> config DEBUG_INFO_BTF
> - bool "Generate BTF type information"
> + tristate "Generate BTF type information"
[Severity: High]
Does this change cause a regression where dependent boolean features are
disabled when CONFIG_DEBUG_INFO_BTF is configured as a module?
In Kconfig, when a bool option depends on an expression that evaluates to
m, its upper bound is restricted. Since a bool cannot hold an m value,
Kconfig evaluates the option to disabled.
Several major kernel features are boolean options that depend directly on
CONFIG_DEBUG_INFO_BTF, including CONFIG_SCHED_CLASS_EXT, CONFIG_NET_SCH_BPF,
CONFIG_DEBUG_INFO_BTF_MODULES, and CONFIG_PROBE_EVENTS_BTF_ARGS.
Setting CONFIG_DEBUG_INFO_BTF to m evaluates these dependencies to m,
which causes these features to be omitted from the build.
Could the dependencies be updated to evaluate to y when BTF is built
as a module, such as using depends on DEBUG_INFO_BTF != n?
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260925211314.5118-1-wanjay@amazon.com?part=9
next prev parent reply other threads:[~2026-09-25 21:33 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-25 21:13 [PATCH bpf-next v2 0/9] bpf: make the vmlinux BTF an on-demand loadable module (CONFIG_DEBUG_INFO_BTF=m) to save ~5.4 MB memory Jay Wang
2026-09-25 21:13 ` [PATCH bpf-next v2 1/9] bpf: pass the vmlinux BTF to btf_parse_module() and let it adopt the data Jay Wang
2026-09-25 21:13 ` [PATCH bpf-next v2 2/9] bpf: split the kfunc, dtor kfunc and struct_ops registration bodies Jay Wang
2026-09-25 21:13 ` [PATCH bpf-next v2 3/9] bpf: fetch the vmlinux BTF where kernel types enter a program Jay Wang
2026-09-25 21:42 ` sashiko-bot
2026-09-25 23:02 ` Jay Wang
2026-09-25 21:13 ` [PATCH bpf-next v2 4/9] bpf: take the vmlinux BTF from the btf_vmlinux module Jay Wang
2026-09-25 21:13 ` [PATCH bpf-next v2 5/9] bpf: defer vmlinux kfunc and struct_ops registrations Jay Wang
2026-09-25 21:13 ` [PATCH bpf-next v2 6/9] bpf: keep module BTF until the vmlinux BTF is available Jay Wang
2026-09-25 21:29 ` sashiko-bot
2026-09-25 23:02 ` Jay Wang
2026-09-25 21:13 ` [PATCH bpf-next v2 7/9] bpf: expose deferred .BTF.base module BTF in sysfs from module load Jay Wang
2026-09-25 21:13 ` [PATCH bpf-next v2 8/9] bpf, trace, net: prepare CONFIG_DEBUG_INFO_BTF checks for a tristate Jay Wang
2026-09-25 21:13 ` [PATCH bpf-next v2 9/9] kbuild, bpf: allow building the vmlinux BTF as a module Jay Wang
2026-09-25 21:33 ` sashiko-bot [this message]
2026-09-25 23:02 ` Jay Wang
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