[PATCH] cpuset: fix RCU lockdep splat in cpuset_print_task_mems_allowed()

Li Zefan
2013-03-12T02:28:39Z

Sasha reported a lockdep warning when OOM was triggered. The reason
is cgroup_name() should be called with rcu_read_lock() held.

Reported-by: Sasha Levin <sasha.levin-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
---

This fix is for 3.10

---
kernel/cpuset.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index c55763b..98d458a 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2599,6 +2599,7 @@ void cpuset_print_task_mems_allowed(struct task_struct *tsk)

struct cgroup *cgrp = task_cs(tsk)->css.cgroup;

+ rcu_read_lock();
spin_lock(&cpuset_buffer_lock);

nodelist_scnprintf(cpuset_nodelist, CPUSET_NODELIST_LEN,
@@ -2607,6 +2608,7 @@ void cpuset_print_task_mems_allowed(struct task_struct *tsk)
tsk->comm, cgroup_name(cgrp), cpuset_nodelist);

spin_unlock(&cpuset_buffer_lock);
+ rcu_read_unlock();
}

/*
--
1.8.0.2