Index: sys/vm/uma_core.c
===================================================================
--- sys/vm/uma_core.c
+++ sys/vm/uma_core.c
@@ -2112,16 +2112,10 @@
 	if (memguard_cmp_zone(zone)) {
 		item = memguard_alloc(zone->uz_size, flags);
 		if (item != NULL) {
-			/*
-			 * Avoid conflict with the use-after-free
-			 * protecting infrastructure from INVARIANTS.
-			 */
 			if (zone->uz_init != NULL &&
-			    zone->uz_init != mtrash_init &&
 			    zone->uz_init(item, zone->uz_size, flags) != 0)
 				return (NULL);
 			if (zone->uz_ctor != NULL &&
-			    zone->uz_ctor != mtrash_ctor &&
 			    zone->uz_ctor(item, zone->uz_size, udata,
 			    flags) != 0) {
 			    	zone->uz_fini(item, zone->uz_size);
@@ -2655,9 +2649,9 @@
                 return;
 #ifdef DEBUG_MEMGUARD
 	if (is_memguard_addr(item)) {
-		if (zone->uz_dtor != NULL && zone->uz_dtor != mtrash_dtor)
+		if (zone->uz_dtor != NULL)
 			zone->uz_dtor(item, zone->uz_size, udata);
-		if (zone->uz_fini != NULL && zone->uz_fini != mtrash_fini)
+		if (zone->uz_fini != NULL)
 			zone->uz_fini(item, zone->uz_size);
 		memguard_free(item);
 		return;
Index: sys/vm/uma_dbg.c
===================================================================
--- sys/vm/uma_dbg.c
+++ sys/vm/uma_dbg.c
@@ -33,6 +33,8 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include "opt_vm.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/bitset.h>
@@ -49,6 +51,7 @@
 #include <vm/uma.h>
 #include <vm/uma_int.h>
 #include <vm/uma_dbg.h>
+#include <vm/memguard.h>
 
 static const uint32_t uma_junk = 0xdeadc0de;
 
@@ -57,7 +60,6 @@
  * prior to subsequent reallocation.
  *
  * Complies with standard ctor arg/return
- *
  */
 int
 trash_ctor(void *mem, int size, void *arg, int flags)
@@ -65,6 +67,11 @@
 	int cnt;
 	uint32_t *p;
 
+#ifdef DEBUG_MEMGUARD
+	if (is_memguard_addr(mem))
+		return (0);
+#endif
+
 	cnt = size / sizeof(uma_junk);
 
 	for (p = mem; cnt > 0; cnt--, p++)
@@ -93,6 +100,11 @@
 	int cnt;
 	uint32_t *p;
 
+#ifdef DEBUG_MEMGUARD
+	if (is_memguard_addr(mem))
+		return;
+#endif
+
 	cnt = size / sizeof(uma_junk);
 
 	for (p = mem; cnt > 0; cnt--, p++)
@@ -131,6 +143,11 @@
 	uint32_t *p = mem;
 	int cnt;
 
+#ifdef DEBUG_MEMGUARD
+	if (is_memguard_addr(mem))
+		return (0);
+#endif
+
 	size -= sizeof(struct malloc_type *);
 	ksp = (struct malloc_type **)mem;
 	ksp += size / sizeof(struct malloc_type *);
@@ -158,6 +175,11 @@
 	int cnt;
 	uint32_t *p;
 
+#ifdef DEBUG_MEMGUARD
+	if (is_memguard_addr(mem))
+		return;
+#endif
+
 	size -= sizeof(struct malloc_type *);
 	cnt = size / sizeof(uma_junk);
 
@@ -176,6 +198,11 @@
 {
 	struct malloc_type **ksp;
 
+#ifdef DEBUG_MEMGUARD
+	if (is_memguard_addr(mem))
+		return (0);
+#endif
+
 	mtrash_dtor(mem, size, NULL);
 
 	ksp = (struct malloc_type **)mem;