From: Jay Wang <wanjay@amazon.com>
To: <sashiko-bot@kernel.org>
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 23:02:52 +0000 [thread overview]
Message-ID: <20260925230252.34602-1-wanjay@amazon.com> (raw)
In-Reply-To: <20260925213305.A7C371F000FF@smtp.kernel.org>
For "depends on DEBUG_INFO_BTF" this does not happen: Kconfig turns an
m upper bound into y for a bool symbol (scripts/kconfig/symbol.c,
sym_calc_visibility()). I checked it with olddefconfig: with
SCHED_CLASS_EXT, NET_SCH_BPF, PROBE_EVENTS_BTF_ARGS, BINFMT_MISC_BPF,
IO_URING_BPF_OPS and DEBUG_INFO_BTF_MODULES enabled, switching
DEBUG_INFO_BTF from y to m changes nothing but BPF_PRELOAD, which the
series excludes on purpose.
Looking at the other uses turned up the reverse case, though: RUST and
GENDWARFKSYMS say "depends on !DEBUG_INFO_BTF", and !m is m, which a
bool again takes as y, so with =m those pahole restrictions no longer
applied. v3 writes them as DEBUG_INFO_BTF=n (patch 8/9):
https://lore.kernel.org/bpf/20260925224229.1850-1-wanjay@amazon.com/
Jay
prev parent reply other threads:[~2026-09-25 23:02 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
2026-09-25 23:02 ` Jay Wang [this message]
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