[PATCH] audit: Protect find_task_by_vpid() with RCU.

[Tetsuo Handa]

[PATCH] audit: Protect find_task_by_vpid() with RCU.

Holding tasklist_lock is no longer sufficient for find_task_by_vpid().
Explicit rcu_read_lock() is required.

Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> 
---
 kernel/audit.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- linux-2.6.33.orig/kernel/audit.c
+++ linux-2.6.33/kernel/audit.c
@@ -468,7 +468,9 @@ static int audit_prepare_user_tty(pid_t 
 	int err;
 
 	read_lock(&tasklist_lock);
+	rcu_read_lock();
 	tsk = find_task_by_vpid(pid);
+	rcu_read_unlock();
 	err = -ESRCH;
 	if (!tsk)
 		goto out;
@@ -882,7 +884,9 @@ static int audit_receive_msg(struct sk_b
 		struct task_struct *tsk;
 
 		read_lock(&tasklist_lock);
+		rcu_read_lock();
 		tsk = find_task_by_vpid(pid);
+		rcu_read_unlock();
 		if (!tsk)
 			err = -ESRCH;
 		else {
@@ -905,7 +909,9 @@ static int audit_receive_msg(struct sk_b
 		if (s->enabled != 0 && s->enabled != 1)
 			return -EINVAL;
 		read_lock(&tasklist_lock);
+		rcu_read_lock();
 		tsk = find_task_by_vpid(pid);
+		rcu_read_unlock();
 		if (!tsk)
 			err = -ESRCH;
 		else {
--
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