diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index fd7472f..dcda521 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -485,7 +485,8 @@
 			    drhd->devices[i]->bus->number == bus &&
 			    drhd->devices[i]->devfn == devfn)
 				return drhd->iommu;
-			if (drhd->devices[i]->subordinate &&
+			if (drhd->devices[i] &&
+			    drhd->devices[i]->subordinate &&
 			    drhd->devices[i]->subordinate->number <= bus &&
 			    drhd->devices[i]->subordinate->subordinate >= bus)
 				return drhd->iommu;