This patch series adds support to freeze the task cgroup hierarchy that is on a default cgroup v2 without going through kernfs interface. For some cases we want to freeze the cgroup of a task based on some signals, doing so from bpf is better than user space which could be too late. Planned users of this feature are: tetragon and systemd when freezing a cgroup hierarchy that could be a K8s pod, container, system service or a user session. Patch 1: cgroup: add cgroup_freeze_no_kn() to freeze a cgroup from bpf Patch 2: bpf: add bpf_task_freeze_cgroup() to freeze the cgroup of a task Patch 3: selftests/bpf: add selftest for bpf_task_freeze_cgroup include/linux/cgroup.h | 2 ++ kernel/bpf/helpers.c | 31 ++++ kernel/cgroup/cgroup.c | 67 ++++++++ tools/testing/selftests/bpf/prog_tests/task_freeze_cgroup.c | 165 +++++++++++++++++++++ tools/testing/selftests/bpf/progs/test_task_freeze_cgroup.c | 110 ++++++++++++++ 5 files changed, 375 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/task_freeze_cgroup.c create mode 100644 tools/testing/selftests/bpf/progs/test_task_freeze_cgroup.c -- 2.34.1
