--- zzzz-none-000/linux-2.6.28.10/kernel/sched_stats.h	2009-05-02 18:54:43.000000000 +0000
+++ puma5-6360-529/linux-2.6.28.10/kernel/sched_stats.h	2010-03-19 15:38:46.000000000 +0000
@@ -303,6 +303,11 @@
 		return;
 
 	sig = tsk->signal;
+	/* see __exit_signal()->task_rq_unlock_wait() */
+	barrier();
+	if (unlikely(!sig))
+		return;
+
 	if (sig->cputime.totals) {
 		struct task_cputime *times;
 
@@ -332,6 +337,11 @@
 		return;
 
 	sig = tsk->signal;
+	/* see __exit_signal()->task_rq_unlock_wait() */
+	barrier();
+	if (unlikely(!sig))
+		return;
+
 	if (sig->cputime.totals) {
 		struct task_cputime *times;