From c731ae1d0f02a300697a8b1564780ad28a6c2013 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Thu, 5 Jun 2014 17:16:30 +0800 Subject: [PATCH] cgroup: disallow disabled controllers on the default hierarchy After booting with cgroup_disable=memory, I still saw memcg files in the default hierarchy, and I can write to them, though it won't take effect. # dmesg ... Disabling memory control group subsystem ... # mount -t cgroup -o __DEVEL__sane_behavior xxx /cgroup # ls /cgroup ... memory.failcnt memory.move_charge_at_immigrate memory.force_empty memory.numa_stat memory.limit_in_bytes memory.oom_control ... # cat /cgroup/memory.usage_in_bytes 0 tj: Minor comment update. Signed-off-by: Li Zefan Signed-off-by: Tejun Heo --- kernel/cgroup.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 3f46165..3edcc8a 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -3069,6 +3069,9 @@ int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts) { int ret; + if (ss->disabled) + return 0; + if (!cfts || cfts[0].name[0] == '\0') return 0; @@ -4678,8 +4681,6 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early) BUG_ON(online_css(css)); - cgrp_dfl_root.subsys_mask |= 1 << ss->id; - mutex_unlock(&cgroup_mutex); } @@ -4758,11 +4759,14 @@ int __init cgroup_init(void) &cgrp_dfl_root.cgrp.e_csets[ssid]); /* - * cftype registration needs kmalloc and can't be done - * during early_init. Register base cftypes separately. + * Setting dfl_root subsys_mask needs to consider the + * disabled flag and cftype registration needs kmalloc, + * both of which aren't available during early_init. */ - if (ss->base_cftypes) + if (!ss->disabled) { + cgrp_dfl_root.subsys_mask |= 1 << ss->id; WARN_ON(cgroup_add_cftypes(ss, ss->base_cftypes)); + } } cgroup_kobj = kobject_create_and_add("cgroup", fs_kobj); -- 2.7.4