diff --git a/sys/arm64/arm64/busdma_bounce.c b/sys/arm64/arm64/busdma_bounce.c
index 57e44cc8742d..8ff364694b49 100644
--- a/sys/arm64/arm64/busdma_bounce.c
+++ b/sys/arm64/arm64/busdma_bounce.c
@@ -767,7 +767,7 @@ bounce_bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map,
 	struct bounce_page *bpage;
 	vm_offset_t datavaddr, tempvaddr;
 
-	if ((bpage = STAILQ_FIRST(&map->bpages)) == NULL)
+	if (map == NULL || (bpage = STAILQ_FIRST(&map->bpages)) == NULL)
 		return;
 
 	/*
diff --git a/sys/x86/x86/busdma_bounce.c b/sys/x86/x86/busdma_bounce.c
index 4826a2b32a0b..9772f33b4fa4 100644
--- a/sys/x86/x86/busdma_bounce.c
+++ b/sys/x86/x86/busdma_bounce.c
@@ -892,7 +892,7 @@ bounce_bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map,
 	vm_offset_t datavaddr, tempvaddr;
 	bus_size_t datacount1, datacount2;
 
-	if ((bpage = STAILQ_FIRST(&map->bpages)) == NULL)
+	if (map == NULL || (bpage = STAILQ_FIRST(&map->bpages)) == NULL)
 		return;
 
 	/*