[LTP] RFC: Proposed cgroup v2 and openat2 test case contributions for LTP

[priyama2]

Hi all,

Following recent discussions on the mailing list and suggestions to 
improve cgroup coverage in LTP, I reviewed the existing tests and kernel 
selftests and came up with a set of potential test cases that I believe 
could strengthen LTP's coverage.

Before I start implementing them, I would appreciate feedback from the 
community to avoid duplicating existing work and to understand which 
areas would be the most valuable to prioritize.


      Candidate test cases


        cgroup v2

  *

    |cgroupv2_no_internal_process01| – Validate enforcement of the "no
    internal process" rule.

  *

    |cgroupv2_controller_propagation01| – Verify controller propagation
    across nested hierarchies.

  *

    |cgroup2_mem_psi01| – Validate memory PSI accounting within cgroups.

  *

    |cgroup2_cpu_burst01| – Verify CPU burst quota behaviour.

  *

    |cgroup2_delegation01| – Test delegation boundaries and permission
    enforcement.

  *

    |cgroup2_io_cost01| – Validate I/O cost controller accounting.


        PSI

  *

    |psi_memory_pressure01|

  *

    |psi_io_pressure01|

  *

    |psi_cpu_pressure01|


        cpuset

  *

    |cpuset_partition_root01|

  *

    |cpuset_partition_hotplug01|


        openat2

  *

    |openat2_symlink01| – Validate |RESOLVE_NO_SYMLINKS| behaviour and
    expected |ELOOP| handling.


      Potential enhancements to existing coverage

I am also considering tests that complement existing functionality by 
focusing on edge cases and error handling, such as:

  *

    Invalid |subtree_control| state transitions and rollback verification

  *

    Threaded mode transition races

  *

    Thread migration rule enforcement

  *

    Hierarchical resource limit validation

  *

    Invalid hierarchy operations and permission boundary checks

  *

    NUMA policy and migration validation

My intention is to focus on deterministic error paths, corner cases, 
concurrency, and integration scenarios that may complement existing LTP 
tests and kernel selftests, rather than duplicating current coverage.

Could the maintainers and community please share:

 1.

    Which of these ideas would be most valuable to implement first?

 2.

    Whether any of these overlap with ongoing work or planned patches?

 3.

    Whether there are other areas in cgroup v2 or related subsystems
    where additional LTP coverage would be more beneficial?

I'd be happy to refine the proposals based on the feedback before 
starting implementation.

Thanks in advance for your guidance.

Best regards,
Priyama