selftests/bpf: Add missing selftests kconfig options

  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>
---
 tools/testing/selftests/bpf/config | 4 ++++
 1 file changed, 4 insertions(+)
  

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
>
  

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Fri,  2 Jun 2023 09:01:08 -0500 you 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.
> 
> [...]

Here is the summary with links:
  - selftests/bpf: Add missing selftests kconfig options
    https://git.kernel.org/bpf/bpf-next/c/3d272c2fa804

You are awesome, thank you!