From: sashiko-bot@kernel.org
To: "Jay Wang" <wanjay@amazon.com>
Cc: linux-input@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
dmitry.torokhov@gmail.com, linux-modules@vger.kernel.org,
"Petr Pavlu" <petr.pavlu@suse.com>,
ojeda@kernel.org, linux-perf-users@vger.kernel.org,
sched-ext@lists.linux.dev, gary@garyguo.net, bpf@vger.kernel.org
Subject: Re: [PATCH bpf-next v4 08/12] bpf: expose deferred .BTF.base module BTF in sysfs from module load
Date: Fri, 02 Oct 2026 09:14:18 +0000 [thread overview]
Message-ID: <20261002091418.A50BE1F00893@smtp.kernel.org> (raw)
In-Reply-To: <20261001225214.12351-9-wanjay@amazon.com>
> A module with a .BTF.base section (built out of tree) that is loaded
> before the vmlinux BTF only gets its /sys/kernel/btf file once the
> vmlinux BTF has been loaded and its BTF relocated, because the raw .BTF
> is only valid against the distilled base and relocation rewrites it in
> place. Until then the module is missing from /sys/kernel/btf, unlike
> with =y, and reading its file cannot trigger the load.
>
> Create the file at module load instead, with its final size: relocation
> only rewrites type ids and string offsets, never the length. Its reader,
> btf_module_sysfs_read_deferred(), has the vmlinux BTF loaded, which parses
> and relocates the kept modules, then waits until this module's BTF is
> published (btf_mod->ready) before serving it, so no unrelocated or
> half-relocated data is ever visible. If the module goes away or its BTF
> turns out unusable first (btf_mod->gone), or the vmlinux BTF cannot be
> loaded, the read fails with -ENODEV.
> [ ... ]
>
> Modules without .BTF.base are unchanged: their data is final and is
> served as is.
>
> Signed-off-by: Jay Wang <wanjay@amazon.com>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261001225214.12351-1-wanjay@amazon.com?part=8
next prev parent reply other threads:[~2026-10-02 9:14 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-01 22:52 [PATCH bpf-next v4 00/12] bpf: make the vmlinux BTF an on-demand loadable module (CONFIG_DEBUG_INFO_BTF=m) to save ~5.4 MB memory Jay Wang
2026-10-01 22:52 ` [PATCH bpf-next v4 01/12] bpf: pass the vmlinux BTF to btf_parse_module() and let it adopt the data Jay Wang
2026-10-02 9:14 ` sashiko-bot
2026-10-01 22:52 ` [PATCH bpf-next v4 02/12] bpf: split the kfunc, dtor kfunc and struct_ops registration bodies Jay Wang
2026-10-02 9:14 ` sashiko-bot
2026-10-01 22:52 ` [PATCH bpf-next v4 03/12] bpf: fetch the vmlinux BTF where kernel types enter a program Jay Wang
2026-10-02 9:14 ` sashiko-bot
2026-10-01 22:52 ` [PATCH bpf-next v4 04/12] bpf: take the vmlinux BTF from the btf_vmlinux module Jay Wang
2026-10-01 23:45 ` bot+bpf-ci
2026-10-02 9:14 ` sashiko-bot
2026-10-02 11:48 ` Alexei Starovoitov
2026-10-01 22:52 ` [PATCH bpf-next v4 05/12] bpf, tracing: load the vmlinux BTF where tracefs and bpffs requests start Jay Wang
2026-10-02 9:14 ` sashiko-bot
2026-10-01 22:52 ` [PATCH bpf-next v4 06/12] bpf: defer vmlinux kfunc and struct_ops registrations Jay Wang
2026-10-02 9:14 ` sashiko-bot
2026-10-01 22:52 ` [PATCH bpf-next v4 07/12] bpf: keep module BTF until the vmlinux BTF is available Jay Wang
2026-10-01 23:45 ` bot+bpf-ci
2026-10-02 9:14 ` sashiko-bot
2026-10-01 22:52 ` [PATCH bpf-next v4 08/12] bpf: expose deferred .BTF.base module BTF in sysfs from module load Jay Wang
2026-10-02 9:14 ` sashiko-bot [this message]
2026-10-01 22:52 ` [PATCH bpf-next v4 09/12] bpf, trace, net: prepare CONFIG_DEBUG_INFO_BTF checks for a tristate Jay Wang
2026-10-02 9:14 ` sashiko-bot
2026-10-05 11:32 ` Nicolas Schier
2026-10-01 22:52 ` [PATCH bpf-next v4 10/12] resolve_btfids: add --btf_link to fill in .BTF.link records Jay Wang
2026-10-01 23:29 ` bot+bpf-ci
2026-10-02 9:14 ` sashiko-bot
2026-10-01 22:52 ` [PATCH bpf-next v4 11/12] tools, samples: take the vmlinux BTF from vmlinux.unstripped first Jay Wang
2026-10-02 9:14 ` sashiko-bot
2026-10-05 11:17 ` Nicolas Schier
2026-10-01 22:52 ` [PATCH bpf-next v4 12/12] kbuild, bpf: allow building the vmlinux BTF as a module Jay Wang
2026-10-02 9:14 ` sashiko-bot
2026-10-02 9:47 ` Alan Maguire
2026-10-02 4:36 ` [PATCH bpf-next v4 00/12] bpf: make the vmlinux BTF an on-demand loadable module (CONFIG_DEBUG_INFO_BTF=m) to save ~5.4 MB memory Ihor Solodrai
2026-10-02 7:34 ` Jay Wang
2026-10-02 10:05 ` Alan Maguire
2026-10-02 20:58 ` Ihor Solodrai
2026-10-03 6:38 ` Alexei Starovoitov
2026-10-03 11:45 ` Alan Maguire
2026-10-03 12:19 ` Alexei Starovoitov
2026-10-04 22:21 ` Jay Wang
2026-10-05 19:01 ` Ihor Solodrai
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