Re: [PATCH bpf-next 1/3] selftests/bpf: Check bpf_mem_cgroup_page_state return value

[JP Kobryn]

On 2/12/26 12:23 AM, Hui Zhu wrote:
> From: Hui Zhu <zhuhui@xxxxxxxxxx>
>
> When back-porting test_progs to different kernel versions, I encountered
> an issue where the test_cgroup_iter_memcg test would falsely pass even
> when bpf_mem_cgroup_page_state() failed.
>
> The problem occurs when test_progs compiled on one kernel version is
> executed on another kernel with different enum values for memory
> statistics (e.g., NR_ANON_MAPPED, NR_FILE_PAGES). [...]

This patch looks good but I think to fully solve this cross-kernel issue
we should use co-re in the bpf program. In your second revision, can you
add an additional patch to make use of bpf_core_enum_value()? This way
instead of relying on enum values in vmlinux.h at compile-time, we use
the btf info at load-time instead to get the proper value for the given
kernel.