[PATCH tip/core/urgent] rcu: protect fork-time cgroup access

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

Add an rcu_read_lock() / rcu_read_unlock() pair to protect a fork-time
cgroup access.  This seems likely to be a false positive.

Located by: Alessio Igor Bogani <abogani@texware.it>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---

 sched.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/sched.c b/kernel/sched.c
index 9ab3cd7..d4bb5e0 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2621,7 +2621,9 @@ void sched_fork(struct task_struct *p, int clone_flags)
 	if (p->sched_class->task_fork)
 		p->sched_class->task_fork(p);
 
+	rcu_read_lock();
 	set_task_cpu(p, cpu);
+	rcu_read_unlock();
 
 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
 	if (likely(sched_info_on()))