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Date:   Fri, 2 Jun 2023 09:27:10 -0700
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Subject: Re: [PATCH] selftests/bpf: Add missing selftests kconfig options
From:   Stanislav Fomichev <sdf@google.com>
To:     David Vernet <void@manifault.com>
Cc:     bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
        andrii@kernel.org, martin.lau@linux.dev, song@kernel.org,
        yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org,
        haoluo@google.com, jolsa@kernel.org, linux-kernel@vger.kernel.org,
        kernel-team@meta.com
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On 06/02, David Vernet wrote:
> Our selftests of course rely on the kernel being built with
> CONFIG_DEBUG_INFO_BTF=y, though this (nor its dependencies of
> CONFIG_DEBUG_INFO=y and CONFIG_DEBUG_INFO_DWARF4=y) are not specified.
> This causes the wrong kernel to be built, and selftests to similarly
> fail to build.
> 
> Additionally, in the BPF selftests kconfig file,
> CONFIG_NF_CONNTRACK_MARK=y is specified, so that the 'u_int32_t mark'
> field will be present in the definition of struct nf_conn.  While a
> dependency of CONFIG_NF_CONNTRACK_MARK=y, CONFIG_NETFILTER_ADVANCED=y,
> should be enabled by default, I've run into instances of
> CONFIG_NF_CONNTRACK_MARK not being set because CONFIG_NETFILTER_ADVANCED
> isn't set, and have to manually enable them with make menuconfig.
> 
> Let's add these missing kconfig options to the file so that the
> necessary dependencies are in place to build vmlinux. Otherwise, we'll
> get errors like this when we try to compile selftests and generate
> vmlinux.h:
> 
> $ cd /path/to/bpf-next
> $ make mrproper; make defconfig
> $ cat tools/testing/selftests/config >> .config
> $ make -j
> ...
> $ cd tools/testing/selftests/bpf
> $ make clean
> $ make -j
> ...
>   LD [M]
>   tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.ko
>   tools/testing/selftests/bpf/tools/build/bpftool/bootstrap/bpftool
>   btf dump file vmlinux format c >
>   tools/testing/selftests/bpf/tools/build/bpftool/vmlinux.h
>   libbpf: failed to find '.BTF' ELF section in
>   vmlinux
>   Error: failed to load BTF from bpf-next/vmlinux:
>   No data available
>   make[1]: *** [Makefile:208:
>   tools/testing/selftests/bpf/tools/build/bpftool/vmlinux.h]
>   Error 195
>   make[1]: *** Deleting file
>   'tools/testing/selftests/bpf/tools/build/bpftool/vmlinux.h'
>   make: *** [Makefile:261:
>   tools/testing/selftests/bpf/tools/sbin/bpftool]
>   Error 2
> 
> Signed-off-by: David Vernet <void@manifault.com>

Acked-by: Stanislav Fomichev <sdf@google.com>

(I've been also setting these manually myself for local testing)

> ---
>  tools/testing/selftests/bpf/config | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
> index 63cd4ab70171..3b350bc31343 100644
> --- a/tools/testing/selftests/bpf/config
> +++ b/tools/testing/selftests/bpf/config
> @@ -13,6 +13,9 @@ CONFIG_CGROUP_BPF=y
>  CONFIG_CRYPTO_HMAC=y
>  CONFIG_CRYPTO_SHA256=y
>  CONFIG_CRYPTO_USER_API_HASH=y
> +CONFIG_DEBUG_INFO=y
> +CONFIG_DEBUG_INFO_BTF=y
> +CONFIG_DEBUG_INFO_DWARF4=y
>  CONFIG_DYNAMIC_FTRACE=y
>  CONFIG_FPROBE=y
>  CONFIG_FTRACE_SYSCALLS=y
> @@ -60,6 +63,7 @@ CONFIG_NET_SCH_INGRESS=y
>  CONFIG_NET_SCHED=y
>  CONFIG_NETDEVSIM=y
>  CONFIG_NETFILTER=y
> +CONFIG_NETFILTER_ADVANCED=y
>  CONFIG_NETFILTER_SYNPROXY=y
>  CONFIG_NETFILTER_XT_CONNMARK=y
>  CONFIG_NETFILTER_XT_MATCH_STATE=y
> -- 
> 2.40.1
>