--- //depot/projects/smpng/sys/kern/kern_thread.c	2004/07/16 21:12:15
+++ //depot/user/jhb/preemption/kern/kern_thread.c	2004/07/16 21:13:27
@@ -1066,9 +1066,11 @@
 	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)) {
 		/*
--- //depot/projects/smpng/sys/kern/subr_sleepqueue.c	2004/07/02 19:16:11
+++ //depot/user/jhb/preemption/kern/subr_sleepqueue.c	2004/07/09 20:08:09
@@ -695,11 +695,13 @@
 	sleepq_release(wchan);
 
 	/* Resume all the threads on the temporary list. */
+	critical_enter();
 	while (!TAILQ_EMPTY(&list)) {
 		td = TAILQ_FIRST(&list);
 		TAILQ_REMOVE(&list, td, td_slpq);
 		sleepq_resume_thread(td, pri);
 	}
+	critical_exit();
 }
 
 /*
--- //depot/projects/smpng/sys/kern/subr_turnstile.c	2004/07/02 19:16:11
+++ //depot/user/jhb/preemption/kern/subr_turnstile.c	2004/07/09 20:08:09
@@ -727,6 +726,7 @@
 	 * in turnstile_wait().  Set a flag to force it to try to acquire
 	 * the lock again instead of blocking.
 	 */
+	critical_enter();
 	while (!TAILQ_EMPTY(&pending_threads)) {
 		td = TAILQ_FIRST(&pending_threads);
 		TAILQ_REMOVE(&pending_threads, td, td_lockq);
@@ -742,6 +742,7 @@
 			MPASS(TD_IS_RUNNING(td) || TD_ON_RUNQ(td));
 		}
 	}
+	critical_exit();
 	mtx_unlock_spin(&sched_lock);
 }
 
--- //depot/projects/smpng/sys/vm/vm_glue.c	2004/07/02 04:13:06
+++ //depot/user/jhb/preemption/vm/vm_glue.c	2004/07/02 20:33:30
@@ -753,6 +753,7 @@
 			vm_thread_swapin(td);
 
 		PROC_LOCK(p);
+		critical_enter();
 		mtx_lock_spin(&sched_lock);
 		p->p_sflag &= ~PS_SWAPPINGIN;
 		p->p_sflag |= PS_INMEM;
@@ -767,6 +768,7 @@
 
 		/* Allow other threads to swap p out now. */
 		--p->p_lock;
+		critical_exit();
 	}
 #endif /* NO_SWAPPING */
 }