From: Jakub Kicinski <kuba@kernel.org>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: "Allan, Bruce W" <bruce.w.allan@intel.com>,
Song Liu <songliubraving@fb.com>,
Andrii Nakryiko <andrii@kernel.org>, bpf <bpf@vger.kernel.org>,
Networking <netdev@vger.kernel.org>,
"Starovoitov, Alexei" <ast@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Kernel Team <Kernel-team@fb.com>,
open list <linux-kernel@vger.kernel.org>,
"rafael@kernel.org" <rafael@kernel.org>,
"jeyu@kernel.org" <jeyu@kernel.org>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Masahiro Yamada <yamada.masahiro@socionext.com>
Subject: Re: [PATCH v4 bpf-next 3/5] kbuild: build kernel module BTFs if BTF is enabled and pahole supports it
Date: Mon, 16 Nov 2020 13:24:15 -0800 [thread overview]
Message-ID: <20201116132409.4a5b8e0b@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <CAEf4BzYSN+XnaA4V3jTLEmoUZO=Yxwp7OAwAY+HOvVEKT5kRFA@mail.gmail.com>
On Mon, 16 Nov 2020 12:34:17 -0800 Andrii Nakryiko wrote:
> > This change, commit 5f9ae91f7c0d ("kbuild: Build kernel module BTFs if BTF is enabled and pahole
> > supports it") currently in net-next, linux-next, etc. breaks the use-case of compiling only a specific
> > kernel module (both in-tree and out-of-tree, e.g. 'make M=drivers/net/ethernet/intel/ice') after
> > first doing a 'make modules_prepare'. Previously, that use-case would result in a warning noting
> > "Symbol info of vmlinux is missing. Unresolved symbol check will be entirely skipped" but now it
> > errors out after noting "No rule to make target 'vmlinux', needed by '<...>.ko'. Stop."
> >
> > Is that intentional?
>
> I wasn't aware of such a use pattern, so definitely not intentional.
> But vmlinux is absolutely necessary to generate the module BTF. So I'm
> wondering what's the proper fix here? Leave it as is (that error
> message is actually surprisingly descriptive, btw)? Force vmlinux
> build? Or skip BTF generation for that module?
For an external out-of-tree module there is no guarantee that vmlinux
will even be on the system, no? So only the last option can work in
that case.
next prev parent reply other threads:[~2020-11-16 21:24 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-10 1:19 [PATCH v4 bpf-next 0/5] Integrate kernel module BTF support Andrii Nakryiko
2020-11-10 1:19 ` [PATCH v4 bpf-next 1/5] bpf: add in-kernel split " Andrii Nakryiko
2020-11-10 17:49 ` Song Liu
2020-11-10 18:31 ` Andrii Nakryiko
2020-11-10 20:14 ` Song Liu
2020-11-10 1:19 ` [PATCH v4 bpf-next 2/5] bpf: assign ID to vmlinux BTF and return extra info for BTF in GET_OBJ_INFO Andrii Nakryiko
2020-11-10 20:24 ` Song Liu
2020-11-10 1:19 ` [PATCH v4 bpf-next 3/5] kbuild: build kernel module BTFs if BTF is enabled and pahole supports it Andrii Nakryiko
2020-11-11 1:04 ` Song Liu
2020-11-16 19:55 ` Allan, Bruce W
2020-11-16 20:34 ` Andrii Nakryiko
2020-11-16 21:24 ` Jakub Kicinski [this message]
2020-11-16 22:35 ` Andrii Nakryiko
2021-11-26 15:16 ` Fabian Grünbichler
2021-12-08 0:08 ` Andrii Nakryiko
2020-11-17 3:44 ` David Ahern
2020-11-10 1:19 ` [PATCH v4 bpf-next 4/5] bpf: load and verify kernel module BTFs Andrii Nakryiko
2020-11-11 7:11 ` kernel test robot
2020-11-11 10:13 ` Jessica Yu
2020-11-11 20:11 ` Andrii Nakryiko
2020-11-13 10:31 ` Jessica Yu
2020-11-13 18:54 ` Andrii Nakryiko
2020-11-10 1:19 ` [PATCH v4 bpf-next 5/5] tools/bpftool: add support for in-kernel and named BTF in `btf show` Andrii Nakryiko
2020-11-11 1:15 ` Song Liu
2020-11-11 4:19 ` Andrii Nakryiko
2020-11-11 7:44 ` Song Liu
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