--- //depot/projects/smpng/sys/kern/kern_thread.c	2005/09/30 17:46:19
+++ //depot/user/jhb/preemption/kern/kern_thread.c	2005/09/30 18:17:36
@@ -948,9 +948,11 @@
 	mtx_assert(&sched_lock, MA_OWNED);
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 	if (!P_SHOULDSTOP(p)) {
+		critical_enter();
 		while ((td = TAILQ_FIRST(&p->p_suspended))) {
 			thread_unsuspend_one(td);
 		}
+		critical_exit();
 	} else if ((P_SHOULDSTOP(p) == P_STOPPED_SINGLE) &&
 	    (p->p_numthreads == p->p_suspcount)) {
 		/*
@@ -985,9 +987,11 @@
 	 * to continue however as this is a bad place to stop.
 	 */
 	if ((p->p_numthreads != 1) && (!P_SHOULDSTOP(p))) {
+		critical_enter();
 		while ((td = TAILQ_FIRST(&p->p_suspended))) {
 			thread_unsuspend_one(td);
 		}
+		critical_exit();
 	}
 	mtx_unlock_spin(&sched_lock);
 }
--- //depot/projects/smpng/sys/vm/vm_glue.c	2005/05/27 14:58:46
+++ //depot/user/jhb/preemption/vm/vm_glue.c	2005/05/27 19:03:12
@@ -556,6 +556,7 @@
 			vm_thread_swapin(td);
 
 		PROC_LOCK(p);
+		critical_enter();
 		mtx_lock_spin(&sched_lock);
 		p->p_sflag &= ~PS_SWAPPINGIN;
 		p->p_sflag |= PS_INMEM;
@@ -570,6 +571,7 @@
 
 		/* Allow other threads to swap p out now. */
 		--p->p_lock;
+		critical_exit();
 	}
 #endif /* NO_SWAPPING */
 }