On Thu, 2010-04-22 at 17:31 +0800, Li Zefan wrote: > with CONFIG_PROVE_RCU, a warning can be triggered when we > resume from suspend: > > ... > include/linux/cgroup.h:533 invoked rcu_dereference_check() without protection! > ... > > task_freezer() calls task_subsys_state(), which needs to be > protected by rcu_read_lock or cgroup_mutex. > > Signed-off-by: Li Zefan <l...@cn.fujitsu.com> > --- > kernel/cgroup_freezer.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c > index 5038f4c..ac76983 100644 > --- a/kernel/cgroup_freezer.c > +++ b/kernel/cgroup_freezer.c > @@ -53,6 +53,7 @@ int cgroup_freezing_or_frozen(struct task_struct *task) > struct freezer *freezer; > enum freezer_state state; > > + rcu_read_lock(); > task_lock(task); > freezer = task_freezer(task); > if (!freezer->css.cgroup->parent) > @@ -60,6 +61,7 @@ int cgroup_freezing_or_frozen(struct task_struct *task) > else > state = freezer->state; > task_unlock(task); > + rcu_read_unlock(); > > return (state == CGROUP_FREEZING) || (state == CGROUP_FROZEN); > }
Hmm cgroup_attach_task() does hold task_lock() over setting tsk->cgroups, so doesn't that also pin the task to the cgroup and thus the cgroup itself? _______________________________________________ Containers mailing list contain...@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list Devel@openvz.org https://openvz.org/mailman/listinfo/devel
