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

From: Greg Kroah-Hartman
Date: Sat Nov 07 2020 - 09:09:31 EST


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@archvm 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@xxxxxxxxxx>
> ---
> 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@xxxxxxxxxxxxxxxxxxx>