diff -r 9a6458e0c3f5 xen/common/cpupool.c
--- a/xen/common/cpupool.c	Tue Feb 01 19:26:36 2011 +0000
+++ b/xen/common/cpupool.c	Thu Feb 03 18:51:40 2011 +0100
@@ -30,6 +30,7 @@
 static int cpupool_moving_cpu = -1;
 static struct cpupool *cpupool_cpu_moving = NULL;
 static cpumask_t cpupool_locked_cpus = CPU_MASK_NONE;
+static int cpupool_debug_move_continue = 0;
 
 static DEFINE_SPINLOCK(cpupool_lock);
 
@@ -226,6 +227,8 @@
                     cpupool_id, cpu, ret);
 
     spin_lock(&cpupool_lock);
+	BUG_ON(!cpupool_debug_move_continue); // Continuation still flagged?
+	BUG_ON(cpu != *((volatile int*)&cpupool_moving_cpu));
     ret = cpu_disable_scheduler(cpu);
     cpu_set(cpu, cpupool_free_cpus);
     if ( !ret )
@@ -236,6 +239,7 @@
         cpupool_put(cpupool_cpu_moving);
         cpupool_cpu_moving = NULL;
     }
+	cpupool_debug_move_continue = 0; // Continuation done.
     spin_unlock(&cpupool_lock);
     return ret;
 }
@@ -300,6 +304,8 @@
     atomic_inc(&c->refcnt);
     cpupool_cpu_moving = c;
     cpu_clear(cpu, c->cpu_valid);
+	BUG_ON(cpupool_debug_move_continue); // Only one outstanding continuation!
+	cpupool_debug_move_continue = 1;
     spin_unlock(&cpupool_lock);
 
     work_cpu = smp_processor_id();
@@ -309,6 +315,7 @@
         if ( work_cpu == cpu )
             work_cpu = next_cpu(cpu, cpupool0->cpu_valid);
     }
+	// SD NOTE:  Why not keep the protection through cpupool_lock until here?
     return continue_hypercall_on_cpu(work_cpu, cpupool_unassign_cpu_helper, c);
 
 out:
diff -r 9a6458e0c3f5 xen/common/sched_credit.c
--- a/xen/common/sched_credit.c	Tue Feb 01 19:26:36 2011 +0000
+++ b/xen/common/sched_credit.c	Thu Feb 03 18:51:40 2011 +0100
@@ -567,6 +567,14 @@
         list_add(&svc->active_vcpu_elem, &sdom->active_vcpu);
         /* Make weight per-vcpu */
         prv->weight += sdom->weight;
+        if (prv->weight < sdom->active_vcpu_count * sdom->weight) {
+            printk("%s, %i: Dom: %i VCPU: %i prv: %p &prv->lock: %p prv->weight: %i "\
+                   "sdom->active_vcpu_count: %i sdom->weight: %i\n",
+                   __FILE__, __LINE__, sdom->dom->domain_id, svc->vcpu->vcpu_id,
+                   (void*) prv, &(prv->lock), prv->weight,
+                   sdom->active_vcpu_count, sdom->weight);
+        }
+        //BUG_ON(prv->weight < sdom->active_vcpu_count * sdom->weight);
         if ( list_empty(&sdom->active_sdom_elem) )
         {
             list_add(&sdom->active_sdom_elem, &prv->active_sdom);
@@ -591,6 +599,14 @@
     sdom->active_vcpu_count--;
     list_del_init(&svc->active_vcpu_elem);
     prv->weight -= sdom->weight;
+    if (prv->weight < sdom->active_vcpu_count * sdom->weight) {
+         printk("%s, %i: Dom: %i VCPU: %i prv: %p &prv->lock: %p prv->weight: %i "\
+                "sdom->active_vcpu_count: %i sdom->weight: %i\n",
+                __FILE__, __LINE__, sdom->dom->domain_id, svc->vcpu->vcpu_id,
+                (void*) prv, &(prv->lock), prv->weight,
+                sdom->active_vcpu_count, sdom->weight);
+    }
+    //BUG_ON(prv->weight < sdom->active_vcpu_count * sdom->weight);
     if ( list_empty(&sdom->active_vcpu) )
     {
         list_del_init(&sdom->active_sdom_elem);
@@ -987,6 +1003,17 @@
         BUG_ON( is_idle_domain(sdom->dom) );
         BUG_ON( sdom->active_vcpu_count == 0 );
         BUG_ON( sdom->weight == 0 );
+        if ( (sdom->weight * sdom->active_vcpu_count) > weight_left ) {
+            struct domain *d = sdom->dom;
+            struct vcpu   *v;
+            for_each_vcpu ( d, v ) {
+                printk("BUG in %s,%i: Domain %i VCPU: %i on processor: %i with "\
+                       "state %i violates invariant!\n",
+                       __FILE__,__LINE__, d->domain_id, v->vcpu_id, v->processor,
+                       v->runstate.state);
+            }
+        }
+
         BUG_ON( (sdom->weight * sdom->active_vcpu_count) > weight_left );
 
         weight_left -= ( sdom->weight * sdom->active_vcpu_count );