Hi, As reported by Kernel Test Robot [1], some pidfd tests fail. This is due to the use of vfork() which introduced some side effects. Similarly, while making it more generic, a previous commit made some Landlock file system tests flaky, and subject to the host's file system mount configuration. This series fixes all these side effects by replacing vfork() with clone3() and CLONE_VFORK, which is cleaner (no arbitrary shared memory) and makes the Kselftest framework more robust. I tried different approaches and I found this one to be the cleaner and less invasive for current test cases. This third series replace improve the clone3_vfork() helper and add Reviewed-by tags. I successfully ran the following tests (using TEST_F and fork/clone/clone3) with this series: - landlock:fs_test - landlock:net_test - landlock:ptrace_test - move_mount_set_group:move_mount_set_group_test - net/af_unix:scm_pidfd - perf_events:remove_on_exec - pidfd:pidfd_getfd_test - pidfd:pidfd_setns_test - seccomp:seccomp_bpf - user_events:abi_test [1] https://lore.kernel.org/oe-lkp/202403291015.1fcfa957-oliver.sang@xxxxxxxxx Previous versions: v1: https://lore.kernel.org/r/20240426172252.1862930-1-mic@xxxxxxxxxxx v2: https://lore.kernel.org/r/20240429130931.2394118-1-mic@xxxxxxxxxxx Regards, Mickaël Salaün (9): selftests/pidfd: Fix config for pidfd_setns_test selftests/landlock: Fix FS tests when run on a private mount point selftests/harness: Fix fixture teardown selftests/harness: Fix interleaved scheduling leading to race conditions selftests/landlock: Do not allocate memory in fixture data selftests/harness: Constify fixture variants selftests/pidfd: Fix wrong expectation selftests/harness: Share _metadata between forked processes selftests/harness: Fix vfork() side effects tools/testing/selftests/kselftest_harness.h | 113 +++++++++++++----- tools/testing/selftests/landlock/fs_test.c | 83 ++++++++----- tools/testing/selftests/pidfd/config | 2 + .../selftests/pidfd/pidfd_setns_test.c | 2 +- 4 files changed, 135 insertions(+), 65 deletions(-) base-commit: e67572cd2204894179d89bd7b984072f19313b03 -- 2.44.0