netdev - Re: [PATCH v2 bpf-next 4/5] bpf: load and verify kernel module BTFs

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Date:   Sat, 7 Nov 2020 15:09:01 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Andrii Nakryiko <andrii@...nel.org>
Cc:     bpf@...r.kernel.org, netdev@...r.kernel.org, ast@...com,
        daniel@...earbox.net, kernel-team@...com,
        linux-kernel@...r.kernel.org, rafael@...nel.org, jeyu@...nel.org,
        Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: Re: [PATCH v2 bpf-next 4/5] bpf: load and verify kernel module BTFs

On Fri, Nov 06, 2020 at 03:02:27PM -0800, Andrii Nakryiko wrote:
> Add kernel module listener that will load/validate and unload module BTF.
> Module BTFs gets ID generated for them, which makes it possible to iterate
> them with existing BTF iteration API. They are given their respective module's
> names, which will get reported through GET_OBJ_INFO API. They are also marked
> as in-kernel BTFs for tooling to distinguish them from user-provided BTFs.
> 
> Also, similarly to vmlinux BTF, kernel module BTFs are exposed through
> sysfs as /sys/kernel/btf/<module-name>. This is convenient for user-space
> tools to inspect module BTF contents and dump their types with existing tools:
> 
> [vmuser@...hvm bpf]$ ls -la /sys/kernel/btf
> total 0
> drwxr-xr-x  2 root root       0 Nov  4 19:46 .
> drwxr-xr-x 13 root root       0 Nov  4 19:46 ..
> 
> ...
> 
> -r--r--r--  1 root root     888 Nov  4 19:46 irqbypass
> -r--r--r--  1 root root  100225 Nov  4 19:46 kvm
> -r--r--r--  1 root root   35401 Nov  4 19:46 kvm_intel
> -r--r--r--  1 root root     120 Nov  4 19:46 pcspkr
> -r--r--r--  1 root root     399 Nov  4 19:46 serio_raw
> -r--r--r--  1 root root 4094095 Nov  4 19:46 vmlinux
> 
> Signed-off-by: Andrii Nakryiko <andrii@...nel.org>
> ---
>  Documentation/ABI/testing/sysfs-kernel-btf |   8 +
>  include/linux/bpf.h                        |   2 +
>  include/linux/module.h                     |   4 +
>  kernel/bpf/btf.c                           | 194 +++++++++++++++++++++
>  kernel/bpf/sysfs_btf.c                     |   2 +-
>  kernel/module.c                            |  32 ++++
>  6 files changed, 241 insertions(+), 1 deletion(-)

Reviewed-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>