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cpuset: fix RCU lockdep splat in cpuset_print_task_mems_allowed()

PATCH Applied Li Zefan 2 participants 2 messages Mar 12, 2013 cgroup

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Li Zefan

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PATCH 1/1 cpuset: fix RCU lockdep splat in cpuset_print_task_mems_allowed()

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 <[email protected]>
Signed-off-by Li Zefan <[email protected]>

---

This fix is for 3.10

---
 kernel/cpuset.c | 2 ++
 1 file changed, 2 insertions(+)
kernel/cpuset.c +2 -0
index c55763b..98d458a 100644
@@ -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();
 }
 
 /*
Signature · 1 line
1.8.0.2