diff options
| author | Tejun Heo <tj@kernel.org> | 2017-01-26 16:47:28 -0500 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2017-01-26 16:47:28 -0500 |
| commit | 07cd12945551b63ecb1a349d50a6d69d1d6feb4a (patch) | |
| tree | 75f65eba7eac9277971082a2d5a4cf1370562c0c /tools/perf/Documentation | |
| parent | 7ce7d89f48834cefece7804d38fc5d85382edf77 (diff) | |
cgroup: don't online subsystems before cgroup_name/path() are operational
While refactoring cgroup creation, a5bca2152036 ("cgroup: factor out
cgroup_create() out of cgroup_mkdir()") incorrectly onlined subsystems
before the new cgroup is associated with it kernfs_node. This is fine
for cgroup proper but cgroup_name/path() depend on the associated
kernfs_node and if a subsystem makes the new cgroup_subsys_state
visible, which they're allowed to after onlining, it can lead to NULL
dereference.
The current code performs cgroup creation and subsystem onlining in
cgroup_create() and cgroup_mkdir() makes the cgroup and subsystems
visible afterwards. There's no reason to online the subsystems early
and we can simply drop cgroup_apply_control_enable() call from
cgroup_create() so that the subsystems are onlined and made visible at
the same time.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Fixes: a5bca2152036 ("cgroup: factor out cgroup_create() out of cgroup_mkdir()")
Cc: stable@vger.kernel.org # v4.6+
Diffstat (limited to 'tools/perf/Documentation')