diff --git a/sys/amd64/amd64/legacy.c b/sys/amd64/amd64/legacy.c
index 0db9cc516ff7..7caa0e936c08 100644
--- a/sys/amd64/amd64/legacy.c
+++ b/sys/amd64/amd64/legacy.c
@@ -437,8 +437,8 @@ nexus_alloc_resource(device_t bus, device_t child, int type, int *rid,
 		return 0;
 #ifdef PC98
 	/* Allocate bushandle. */
-	rv->r_bushandle =
-	    malloc(sizeof *rv->r_bushandle, M_BUSSPACEHANDLE, M_NOWAIT);
+	rv->r_bushandle = malloc(sizeof *rv->r_bushandle, M_BUSSPACEHANDLE,
+				 M_NOWAIT | M_ZERO);
 	if (rv->r_bushandle == 0) {
 		rman_release_resource(rv);
 		return 0;
diff --git a/sys/amd64/amd64/nexus.c b/sys/amd64/amd64/nexus.c
index 0db9cc516ff7..7caa0e936c08 100644
--- a/sys/amd64/amd64/nexus.c
+++ b/sys/amd64/amd64/nexus.c
@@ -437,8 +437,8 @@ nexus_alloc_resource(device_t bus, device_t child, int type, int *rid,
 		return 0;
 #ifdef PC98
 	/* Allocate bushandle. */
-	rv->r_bushandle =
-	    malloc(sizeof *rv->r_bushandle, M_BUSSPACEHANDLE, M_NOWAIT);
+	rv->r_bushandle = malloc(sizeof *rv->r_bushandle, M_BUSSPACEHANDLE,
+				 M_NOWAIT | M_ZERO);
 	if (rv->r_bushandle == 0) {
 		rman_release_resource(rv);
 		return 0;
diff --git a/sys/i386/i386/legacy.c b/sys/i386/i386/legacy.c
index 0db9cc516ff7..7caa0e936c08 100644
--- a/sys/i386/i386/legacy.c
+++ b/sys/i386/i386/legacy.c
@@ -437,8 +437,8 @@ nexus_alloc_resource(device_t bus, device_t child, int type, int *rid,
 		return 0;
 #ifdef PC98
 	/* Allocate bushandle. */
-	rv->r_bushandle =
-	    malloc(sizeof *rv->r_bushandle, M_BUSSPACEHANDLE, M_NOWAIT);
+	rv->r_bushandle = malloc(sizeof *rv->r_bushandle, M_BUSSPACEHANDLE,
+				 M_NOWAIT | M_ZERO);
 	if (rv->r_bushandle == 0) {
 		rman_release_resource(rv);
 		return 0;
diff --git a/sys/i386/i386/nexus.c b/sys/i386/i386/nexus.c
index 0db9cc516ff7..7caa0e936c08 100644
--- a/sys/i386/i386/nexus.c
+++ b/sys/i386/i386/nexus.c
@@ -437,8 +437,8 @@ nexus_alloc_resource(device_t bus, device_t child, int type, int *rid,
 		return 0;
 #ifdef PC98
 	/* Allocate bushandle. */
-	rv->r_bushandle =
-	    malloc(sizeof *rv->r_bushandle, M_BUSSPACEHANDLE, M_NOWAIT);
+	rv->r_bushandle = malloc(sizeof *rv->r_bushandle, M_BUSSPACEHANDLE,
+				 M_NOWAIT | M_ZERO);
 	if (rv->r_bushandle == 0) {
 		rman_release_resource(rv);
 		return 0;