Index: sys/kern/kern_descrip.c
===================================================================
--- sys/kern/kern_descrip.c
+++ sys/kern/kern_descrip.c
@@ -4366,7 +4366,7 @@
 	pwd_smr = uma_zone_get_smr(pwd_zone);
 	mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF);
 }
-SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL);
+SYSINIT(select, SI_SUB_INTRINSIC - 1, SI_ORDER_ANY, filelistinit, NULL);
 
 /*-------------------------------------------------------------------*/
 
Index: sys/kern/subr_smr.c
===================================================================
--- sys/kern/subr_smr.c
+++ sys/kern/subr_smr.c
@@ -622,12 +622,12 @@
 /*
  * Initialize the UMA slab zone.
  */
-void
-smr_init(void)
+static void
+smr_init(void *arg __unused)
 {
-
 	smr_shared_zone = uma_zcreate("SMR SHARED", sizeof(struct smr_shared),
 	    NULL, NULL, NULL, NULL, (CACHE_LINE_SIZE * 2) - 1, 0);
 	smr_zone = uma_zcreate("SMR CPU", sizeof(struct smr),
 	    NULL, NULL, NULL, NULL, (CACHE_LINE_SIZE * 2) - 1, UMA_ZONE_PCPU);
 }
+SYSINIT(smr_init, SI_SUB_SMR, SI_ORDER_FIRST, smr_init, NULL);
Index: sys/sys/kernel.h
===================================================================
--- sys/sys/kernel.h
+++ sys/sys/kernel.h
@@ -106,6 +106,7 @@
 	SI_SUB_VNET_PRELINK	= 0x1E00000,	/* vnet init before modules */
 	SI_SUB_KLD		= 0x2000000,	/* KLD and module setup */
 	SI_SUB_CPU		= 0x2100000,	/* CPU resource(s)*/
+	SI_SUB_SMR		= 0x2101000,	/* SMR zones can be used */
 	SI_SUB_RACCT		= 0x2110000,	/* resource accounting */
 	SI_SUB_KDTRACE		= 0x2140000,	/* Kernel dtrace hooks */
 	SI_SUB_RANDOM		= 0x2160000,	/* random number generator */
Index: sys/sys/smr.h
===================================================================
--- sys/sys/smr.h
+++ sys/sys/smr.h
@@ -255,7 +255,4 @@
         smr_wait(smr, smr_advance(smr));
 }
 
-/* Only at startup. */
-void smr_init(void);
-
 #endif	/* _SYS_SMR_H_ */
Index: sys/vm/uma_core.c
===================================================================
--- sys/vm/uma_core.c
+++ sys/vm/uma_core.c
@@ -2230,6 +2230,9 @@
 		keg->uk_flags |= UMA_ZONE_ROUNDROBIN;
 #endif
 
+	KASSERT(booted >= BOOT_KVA || (keg->uk_flags & UMA_ZONE_PCPU) == 0,
+	    ("%s: early pcpu keg %s", __func__, keg->uk_name));
+
 	/*
 	 * If we haven't booted yet we need allocations to go through the
 	 * startup cache until the vm is ready.
@@ -2307,12 +2310,11 @@
 		return;
 	KEG_GET(zone, keg);
 
+	/* Switch to the real allocator. */
 	if (keg->uk_allocf == startup_alloc) {
-		/* Switch to the real allocator. */
-		if (keg->uk_flags & UMA_ZONE_PCPU)
-			keg->uk_allocf = pcpu_page_alloc;
-		else if ((keg->uk_flags & UMA_ZONE_CONTIG) != 0 &&
-		    keg->uk_ppera > 1)
+		KASSERT((keg->uk_flags & UMA_ZONE_PCPU) == 0,
+		    ("%s: early pcpu keg %s", __func__, keg->uk_name));
+		if ((keg->uk_flags & UMA_ZONE_CONTIG) != 0 && keg->uk_ppera > 1)
 			keg->uk_allocf = contig_alloc;
 		else
 			keg->uk_allocf = page_alloc;
@@ -2870,7 +2872,6 @@
 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZFLAG_INTERNAL);
 
 	bucket_init();
-	smr_init();
 }
 
 #ifndef UMA_MD_SMALL_ALLOC
@@ -3300,7 +3301,7 @@
 #ifdef UMA_ZALLOC_DEBUG
 	void *item;
 
-	KASSERT((zone->uz_flags & UMA_ZONE_SMR) != 0,
+	KASSERT(booted < BOOT_RUNNING || (zone->uz_flags & UMA_ZONE_SMR) != 0,
 	    ("uma_zalloc_arg: called with non-SMR zone.\n"));
 	if (uma_zalloc_debug(zone, &item, NULL, flags) == EJUSTRETURN)
 		return (item);
@@ -4643,7 +4644,8 @@
 uma_zone_set_smr(uma_zone_t zone, smr_t smr)
 {
 
-	ZONE_ASSERT_COLD(zone);
+	if (booted >= BOOT_RUNNING)
+		ZONE_ASSERT_COLD(zone);
 
 	KASSERT(smr != NULL, ("Got NULL smr"));
 	KASSERT((zone->uz_flags & UMA_ZONE_SMR) == 0,
Index: sys/vm/vm_radix.c
===================================================================
--- sys/vm/vm_radix.c
+++ sys/vm/vm_radix.c
@@ -375,10 +375,17 @@
 
 	vm_radix_node_zone = uma_zcreate("RADIX NODE",
 	    sizeof(struct vm_radix_node), NULL, NULL, NULL, NULL,
-	    VM_RADIX_PAD, UMA_ZONE_VM | UMA_ZONE_SMR | UMA_ZONE_ZINIT);
-	vm_radix_smr = uma_zone_get_smr(vm_radix_node_zone);
+	    VM_RADIX_PAD, UMA_ZONE_VM | UMA_ZONE_ZINIT);
 }
 
+static void
+vm_radix_zinit2(void)
+{
+	vm_radix_smr = smr_create("RADIX NODE", 0, 0);
+	uma_zone_set_smr(vm_radix_node_zone, vm_radix_smr);
+}
+SYSINIT(vm_radix_zinit2, SI_SUB_SMR, SI_ORDER_ANY, vm_radix_zinit2, NULL);
+
 /*
  * Inserts the key-value pair into the trie.
  * Panics if the key already exists.