diff --git a/[refs] b/[refs]
index b91c7b7e3e12..31a6766a1d86 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e0c1e9bf81badc7ba59e120d6218101903d5d103
+refs/heads/master: 5192d84e4c32cd335fd572e5ff0712041f45f7e7
diff --git a/trunk/arch/x86_64/kernel/pci-gart.c b/trunk/arch/x86_64/kernel/pci-gart.c
index 9d3d76c85ae7..2480d3f08a47 100644
--- a/trunk/arch/x86_64/kernel/pci-gart.c
+++ b/trunk/arch/x86_64/kernel/pci-gart.c
@@ -639,6 +639,14 @@ static int __init pci_iommu_init(void)
 		return -1;
 	}
 
+	i = 0;
+	for_all_nb(dev)
+		i++;
+	if (i > MAX_NB) {
+		printk(KERN_ERR "PCI-GART: Too many northbridges (%ld). Disabled\n", i);
+		return -1;
+	}
+
 	printk(KERN_INFO "PCI-DMA: using GART IOMMU.\n");
 	aper_size = info.aper_size * 1024 * 1024;	
 	iommu_size = check_iommu_size(info.aper_base, aper_size);