diff -urN oldtree/fs/proc/array.c newtree/fs/proc/array.c
--- oldtree/fs/proc/array.c	2006-08-19 09:10:58.000000000 -0400
+++ newtree/fs/proc/array.c	2006-08-19 17:02:54.223458500 -0400
@@ -357,6 +357,8 @@
 	sigemptyset(&sigign);
 	sigemptyset(&sigcatch);
 	cutime = cstime = utime = stime = cputime_zero;
+	
+	mutex_lock(&tty_mutex);
 	read_lock(&tasklist_lock);
 	if (task->sighand) {
 		spin_lock_irq(&task->sighand->siglock);
@@ -398,6 +400,7 @@
 	}
 	ppid = pid_alive(task) ? task->group_leader->real_parent->tgid : 0;
 	read_unlock(&tasklist_lock);
+	mutex_unlock(&tty_mutex);
 
 	if (!whole || num_threads<2)
 		wchan = get_wchan(task);