On Wed, Aug 24, 2022 at 4:31 PM Hao Luo <haoluo@xxxxxxxxxx> wrote: > + > + for (i = 0; i < N_CGROUPS; i++) { > + fd = create_and_get_cgroup(cgroups[i].path); > + if (!ASSERT_GE(fd, 0, "create_and_get_cgroup")) > + return fd; > + > + cgroups[i].fd = fd; > + cgroups[i].id = get_cgroup_id(cgroups[i].path); > + > + /* > + * Enable memcg controller for the entire hierarchy. > + * Note that stats are collected for all cgroups in a hierarchy > + * with memcg enabled anyway, but are only exposed for cgroups > + * that have memcg enabled. > + */ > + if (i < N_NON_LEAF_CGROUPS) { > + err = enable_controllers(cgroups[i].path, "memory"); > + if (!ASSERT_OK(err, "enable_controllers")) > + return err; > + } > + } It passes BPF CI, but fails in my setup with: # ./test_progs -t cgroup_hier -vv bpf_testmod.ko is already unloaded. Loading bpf_testmod.ko... Successfully loaded bpf_testmod.ko. setup_bpffs:PASS:mount 0 nsec setup_cgroups:PASS:setup_cgroup_environment 0 nsec setup_cgroups:PASS:get_root_cgroup 0 nsec setup_cgroups:PASS:create_and_get_cgroup 0 nsec (cgroup_helpers.c:92: errno: No such file or directory) Enabling controller memory: /mnt/cgroup-test-work-dir6526//test/cgroup.subtree_control setup_cgroups:FAIL:enable_controllers unexpected error: 1 (errno 2) cleanup_bpffs:FAIL:rmdir /sys/fs/bpf/vmscan/ unexpected error: -1 (errno 2) #36 cgroup_hierarchical_stats:FAIL Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED How do I debug it?