WSL2-Linux-Kernel/kernel/cgroup
Tejun Heo aa0533f4f7 cgroup: fix rule checking for threaded mode switching
commit d1897c9538 upstream.

A domain cgroup isn't allowed to be turned threaded if its subtree is
populated or domain controllers are enabled.  cgroup_enable_threaded()
depended on cgroup_can_be_thread_root() test to enforce this rule.  A
parent which has populated domain descendants or have domain
controllers enabled can't become a thread root, so the above rules are
enforced automatically.

However, for the root cgroup which can host mixed domain and threaded
children, cgroup_can_be_thread_root() doesn't check any of those
conditions and thus first level cgroups ends up escaping those rules.

This patch fixes the bug by adding explicit checks for those rules in
cgroup_enable_threaded().

Reported-by: Michael Kerrisk (man-pages) <mtk.manpages@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 8cfd8147df ("cgroup: implement cgroup v2 thread support")
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-28 18:24:37 +02:00
..
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cgroup-internal.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cgroup-v1.c cgroup: Fix deadlock in cpu hotplug path 2018-03-03 10:24:26 +01:00
cgroup.c cgroup: fix rule checking for threaded mode switching 2018-03-28 18:24:37 +02:00
cpuset.c Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-09-12 11:30:56 -07:00
debug.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
freezer.c cgroup: add @flags to css_task_iter_start() and implement CSS_TASK_ITER_PROCS 2017-07-21 11:14:51 -04:00
namespace.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pids.c cgroup: implement cgroup v2 thread support 2017-07-21 11:14:51 -04:00
rdma.c