Debugging patch to see if we can figure out why some systems fail to boot or
initialise hardware correctly. If this fixes a problem for you, PLEASE report
it back!

Index: linux-2.6.31-bfs/init/main.c
===================================================================
--- linux-2.6.31-bfs.orig/init/main.c	2009-09-14 09:33:13.977147049 +1000
+++ linux-2.6.31-bfs/init/main.c	2009-09-14 15:00:57.003282292 +1000
@@ -829,6 +829,8 @@
 	kernel_execve(init_filename, argv_init, envp_init);
 }
 
+int fragile_boot __read_mostly = 1;
+
 /* This is a non __init function. Force it to be noinline otherwise gcc
  * makes it inline to init() and it becomes part of init.text section
  */
@@ -851,6 +853,9 @@
 
 	current->signal->flags |= SIGNAL_UNKILLABLE;
 
+	printk(KERN_INFO "Disabling Fragile boot.\n");
+	fragile_boot = 0;
+
 	if (ramdisk_execute_command) {
 		run_init_process(ramdisk_execute_command);
 		printk(KERN_WARNING "Failed to execute %s\n",
Index: linux-2.6.31-bfs/kernel/sched_bfs.c
===================================================================
--- linux-2.6.31-bfs.orig/kernel/sched_bfs.c	2009-09-14 09:33:13.997144999 +1000
+++ linux-2.6.31-bfs/kernel/sched_bfs.c	2009-09-14 14:59:33.868278531 +1000
@@ -166,6 +166,7 @@
 #ifdef CONFIG_SMP
 	cpumask_t cpu_idle_map;
 #endif
+	void (*wunt)(struct task_struct *, struct rq *, unsigned long);
 };
 
 static struct global_rq grq;
@@ -1167,13 +1168,11 @@
  * that must be done for every newly created context, then puts the task
  * on the runqueue and wakes it.
  */
-void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
+static void
+normal_wunt(struct task_struct *p, struct rq *rq, unsigned long clone_flags)
 {
-	struct task_struct *parent;
-	unsigned long flags;
-	struct rq *rq  = time_task_grq_lock(p, &flags);
+	struct task_struct *parent = p->parent;
 
-	parent = p->parent;
 	BUG_ON(p->state != TASK_RUNNING);
 	set_task_cpu(p, task_cpu(parent));
 
@@ -1190,7 +1189,40 @@
 			rq->preempt_next = p;
 	} else
 		try_preempt(p, rq);
-	task_grq_unlock(&flags);
+}
+
+extern int fragile_boot;
+
+/* Fragile version to not wake to other cpus during boot */
+static void
+fb_wunt(struct task_struct *p, struct rq *rq, unsigned long clone_flags)
+{
+	struct task_struct *parent = p->parent;
+
+	BUG_ON(p->state != TASK_RUNNING);
+	set_task_cpu(p, task_cpu(parent));
+
+	activate_task(p, rq);
+	trace_sched_wakeup_new(rq, p, 1);
+	/* Child always runs first */
+	set_tsk_need_resched(parent);
+	rq->preempt_next = p;
+	/*
+	 * fragile_boot is set initially and unset only once just before
+	 * init so we change to normal wunt from here onwards, the ->wunt
+	 * pointer is protected by grq lock.
+	 */
+	if (!fragile_boot)
+		grq.wunt = normal_wunt;
+}
+
+void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
+{
+	unsigned long flags;
+
+	struct rq *rq = time_task_grq_lock(p, &flags);
+	grq.wunt(p, rq, clone_flags);
+	grq_unlock_irqrestore(&flags);
 }
 
 /*
@@ -5937,6 +5969,7 @@
 	cpus_clear(grq.cpu_idle_map);
 #endif
 	spin_lock_init(&grq.lock);
+	grq.wunt = fb_wunt;
 	for_each_possible_cpu(i) {
 		struct rq *rq;