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-rw-r--r--kernel/cgroup_freezer.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index 59e9ef6aab40..e5c0244962b0 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -15,6 +15,7 @@
*/
#include <linux/module.h>
+#include <linux/slab.h>
#include <linux/cgroup.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
@@ -47,17 +48,20 @@ static inline struct freezer *task_freezer(struct task_struct *task)
struct freezer, css);
}
-int cgroup_frozen(struct task_struct *task)
+int cgroup_freezing_or_frozen(struct task_struct *task)
{
struct freezer *freezer;
enum freezer_state state;
task_lock(task);
freezer = task_freezer(task);
- state = freezer->state;
+ if (!freezer->css.cgroup->parent)
+ state = CGROUP_THAWED; /* root cgroup can't be frozen */
+ else
+ state = freezer->state;
task_unlock(task);
- return state == CGROUP_FROZEN;
+ return (state == CGROUP_FREEZING) || (state == CGROUP_FROZEN);
}
/*
@@ -201,9 +205,12 @@ static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
* No lock is needed, since the task isn't on tasklist yet,
* so it can't be moved to another cgroup, which means the
* freezer won't be removed and will be valid during this
- * function call.
+ * function call. Nevertheless, apply RCU read-side critical
+ * section to suppress RCU lockdep false positives.
*/
+ rcu_read_lock();
freezer = task_freezer(task);
+ rcu_read_unlock();
/*
* The root cgroup is non-freezable, so we can skip the