Re: [PATCH bpf-next v3 0/3] Fix test_cgroup_iter_memcg issues found during back-porting

[Emil Tsalapatis]

On Sat Feb 28, 2026 at 2:11 AM EST, Hui Zhu wrote:
> From: Hui Zhu <zhuhui@xxxxxxxxxx>
>
> While back-porting "mm: bpf kfuncs to access memcg data", I
> encountered issues with test_cgroup_iter_memcg, specifically
> in test_kmem.
>
> These patches are my fixes for the problems I encountered.
>

Nit: Could you be a bit more descriptive about the series' contents?
Cover letters normally focus on what what the patch does - for example
the issues being found during backporting is not pertinent to the patchset 
itself, because the issues are still present on bpf-next.

> Changelog:
> v3:
> According to the comments of JP Kobryn, remove kmem subtest from
> cgroup_iter_memcg and fix assertion string in test_pgfault.
> v2:
> According to the comments of JP Kobryn, added bpf_core_enum_value()
> usage in the BPF program to handle cross-kernel enum value differences
> at load-time instead of compile-time.
> Dropped the mm/memcontrol.c patch.
> Modified test_kmem handling: instead of skipping when nokmem is set,
> verify that kmem value is zero as expected.
> According to the comments of bot, fixed assertion message: changed
> "bpf_mem_cgroup_page_state" to "bpf_mem_cgroup_vm_events" for PGFAULT
> check.
>
> Hui Zhu (3):
>   selftests/bpf: Remove kmem subtest from cgroup_iter_memcg
>   bpf: Use bpf_core_enum_value for stats in cgroup_iter_memcg
>   selftests/bpf: Check bpf_mem_cgroup_page_state return value
>
>  .../testing/selftests/bpf/cgroup_iter_memcg.h |  2 -
>  .../bpf/prog_tests/cgroup_iter_memcg.c        | 38 +++++--------------
>  .../selftests/bpf/progs/cgroup_iter_memcg.c   | 18 ++++++---
>  3 files changed, 22 insertions(+), 36 deletions(-)