memcontrol: rcu_read_lock() to protect mm_match_cgroup()
mm_match_cgroup() calls cgroup_subsys_state().
We must use rcu_read_lock() to protect cgroup_subsys_state().
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 472efd0..2de6504 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -61,8 +61,15 @@
extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
-#define mm_match_cgroup(mm, cgroup) \
- ((cgroup) == mem_cgroup_from_task((mm)->owner))
+static inline
+int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup)
+{
+ struct mem_cgroup *mem;
+ rcu_read_lock();
+ mem = mem_cgroup_from_task((mm)->owner);
+ rcu_read_unlock();
+ return cgroup == mem;
+}
extern int
mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr);