diff --git a/sys/dev/disk/mpt/mpt_user.c b/sys/dev/disk/mpt/mpt_user.c
--- a/sys/dev/disk/mpt/mpt_user.c
+++ b/sys/dev/disk/mpt/mpt_user.c
@@ -201,7 +201,7 @@
 	if (error)
 		return (error);
 	error = bus_dmamem_alloc(page_mem->tag, &page_mem->vaddr,
-	    BUS_DMA_NOWAIT | BUS_DMA_COHERENT, &page_mem->map);
+	    BUS_DMA_NOWAIT | BUS_DMA_COHERENT | BUS_DMA_ZERO, &page_mem->map);
 	if (error) {
 		bus_dma_tag_destroy(page_mem->tag);
 		return (error);