[PATCH] fix deadlock over proc_lock

From: Manfred Spraul <manfred@colorfullife.com>

Martin found out what caused the deadlocks with 2.5.70 and SDET: I forgot
to initialize proc_lock during fork().  Usually this works, because the
parent lock is unlocked.  But a proc lookup during fork can cause it to be
locked, and then the system locks up.

kernel/fork.c

@@ -846,6 +846,7 @@ struct task_struct *copy_process(unsigned long clone_flags,
 	p->vfork_done = NULL;
 	spin_lock_init(&p->alloc_lock);
 	spin_lock_init(&p->switch_lock);
+	spin_lock_init(&p->proc_lock);
 
 	clear_tsk_thread_flag(p, TIF_SIGPENDING);
 	init_sigpending(&p->pending);