diff --git a/arch/x86/kernel/pci-nommu_64.c b/arch/x86/kernel/pci-nommu_64.c
index c6901e7..8d036ae 100644
--- a/arch/x86/kernel/pci-nommu_64.c
+++ b/arch/x86/kernel/pci-nommu_64.c
@@ -30,6 +30,7 @@
 	       int direction)
 {
 	dma_addr_t bus = paddr;
+	WARN_ON(size == 0);
 	if (!check_addr("map_single", hwdev, bus, size))
 				return bad_dma_address;
 	flush_write_buffers();
@@ -58,6 +59,8 @@
 	struct scatterlist *s;
 	int i;
 
+	WARN_ON(nents == 0 || sg[0].length == 0);
+
 	for_each_sg(sg, s, nents, i) {
 		BUG_ON(!sg_page(s));
 		s->dma_address = sg_phys(s);