Index: sys/kern/kern_proc.c
===================================================================
--- sys/kern/kern_proc.c
+++ sys/kern/kern_proc.c
@@ -128,7 +128,7 @@
 u_long pidhashlock;
 struct pgrphashhead *pgrphashtbl;
 u_long pgrphash;
-struct proclist allproc;
+struct proclist allproc = LIST_HEAD_INITIALIZER(allproc);
 struct sx __exclusive_cache_line allproc_lock;
 struct sx __exclusive_cache_line proctree_lock;
 struct mtx __exclusive_cache_line ppeers_lock;
@@ -185,7 +185,6 @@
 	sx_init(&proctree_lock, "proctree");
 	mtx_init(&ppeers_lock, "p_peers", NULL, MTX_DEF);
 	mtx_init(&procid_lock, "procid", NULL, MTX_DEF);
-	LIST_INIT(&allproc);
 	pidhashtbl = hashinit(maxproc / 4, M_PROC, &pidhash);
 	pidhashlock = (pidhash + 1) / 64;
 	if (pidhashlock > 0)
Index: sys/kern/subr_kdb.c
===================================================================
--- sys/kern/subr_kdb.c
+++ sys/kern/subr_kdb.c
@@ -608,6 +608,10 @@
 	struct thread *thr;
 	u_int i;
 
+	/* This function may be called early. */
+	if (LIST_EMPTY(&allproc))
+		return (&thread0);
+
 	for (i = 0; i <= pidhash; i++) {
 		LIST_FOREACH(p, &pidhashtbl[i], p_hash) {
 			thr = FIRST_THREAD_IN_PROC(p);
@@ -647,6 +651,10 @@
 	struct proc *p;
 	u_int hash;
 
+	/* This function may be called early. */
+	if (LIST_EMPTY(&allproc))
+		return (NULL);
+
 	p = thr->td_proc;
 	thr = TAILQ_NEXT(thr, td_plist);
 	if (thr != NULL)