[tip:sched/core] sched: Add missing rcu_dereference() around -> real_parent usage

[tip-bot for Kees Cook <keescook@chromium.org>]

Commit-ID:  07cde2608a3b5c66515363f1b53623b1536b9785
Gitweb:     http://git.kernel.org/tip/07cde2608a3b5c66515363f1b53623b1536b9785
Author:     Kees Cook <keescook@chromium.org>
AuthorDate: Thu, 15 Dec 2011 08:49:18 -0800
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 16 Dec 2011 09:42:09 +0100

sched: Add missing rcu_dereference() around ->real_parent usage

Wrap another ->real_parent dereference while under rcu_read_lock.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Link: http://lkml.kernel.org/r/20111215164918.GA13003@www.outflux.net
[ tidied up the changelog ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/sched/core.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 3c5b21e..c7ea688 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4784,7 +4784,7 @@ void sched_show_task(struct task_struct *p)
 	free = stack_not_used(p);
 #endif
 	printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
-		task_pid_nr(p), task_pid_nr(p->real_parent),
+		task_pid_nr(p), task_pid_nr(rcu_dereference(p->real_parent)),
 		(unsigned long)task_thread_info(p)->flags);
 
 	show_stack(p, NULL);