diff --git a/hw/e1000.c b/hw/e1000.c
index 1729db28e1..b0fe917342 100644
--- a/hw/e1000.c
+++ b/hw/e1000.c
@@ -1063,6 +1063,9 @@ pci_e1000_init(PCIBus *bus, NICInfo *nd, int devfn)
     d = (E1000State *)pci_register_device(bus, "e1000",
                 sizeof(E1000State), devfn, NULL, NULL);
 
+    if (!d)
+	return NULL;
+
     pci_conf = d->dev.config;
     memset(pci_conf, 0, 256);
 
diff --git a/hw/eepro100.c b/hw/eepro100.c
index 18d81153bf..235e598725 100644
--- a/hw/eepro100.c
+++ b/hw/eepro100.c
@@ -1739,6 +1739,9 @@ static PCIDevice *nic_init(PCIBus * bus, NICInfo * nd, uint32_t device)
     d = (PCIEEPRO100State *) pci_register_device(bus, nd->model,
                                                  sizeof(PCIEEPRO100State), -1,
                                                  NULL, NULL);
+    if (!d)
+        return NULL;
+
     d->dev.unregister = pci_nic_uninit;
 
     s = &d->eepro100;
diff --git a/hw/ne2000.c b/hw/ne2000.c
index 99612e2589..613ac411f8 100644
--- a/hw/ne2000.c
+++ b/hw/ne2000.c
@@ -810,6 +810,9 @@ PCIDevice *pci_ne2000_init(PCIBus *bus, NICInfo *nd, int devfn)
                                               "NE2000", sizeof(PCINE2000State),
                                               devfn,
                                               NULL, NULL);
+    if (!d)
+       return NULL;
+
     pci_conf = d->dev.config;
     pci_config_set_vendor_id(pci_conf, PCI_VENDOR_ID_REALTEK);
     pci_config_set_device_id(pci_conf, PCI_DEVICE_ID_REALTEK_8029);
diff --git a/hw/pcnet.c b/hw/pcnet.c
index acbaee6cdd..654340b68f 100644
--- a/hw/pcnet.c
+++ b/hw/pcnet.c
@@ -2023,7 +2023,11 @@ PCIDevice *pci_pcnet_init(PCIBus *bus, NICInfo *nd, int devfn)
 
     d = (PCNetState *)pci_register_device(bus, "PCNet", sizeof(PCNetState),
                                           devfn, NULL, NULL);
+    if (!d)
+	return NULL;
+
     d->dev.unregister = pci_pcnet_uninit;
+
     pci_conf = d->dev.config;
 
     pci_config_set_vendor_id(pci_conf, PCI_VENDOR_ID_AMD);
diff --git a/hw/rtl8139.c b/hw/rtl8139.c
index 0093ff4a93..19c7623c58 100644
--- a/hw/rtl8139.c
+++ b/hw/rtl8139.c
@@ -3451,7 +3451,11 @@ PCIDevice *pci_rtl8139_init(PCIBus *bus, NICInfo *nd, int devfn)
                                               "RTL8139", sizeof(PCIRTL8139State),
                                               devfn,
                                               NULL, NULL);
+    if (!d)
+	return NULL;
+
     d->dev.unregister = pci_rtl8139_uninit;
+
     pci_conf = d->dev.config;
     pci_config_set_vendor_id(pci_conf, PCI_VENDOR_ID_REALTEK);
     pci_config_set_device_id(pci_conf, PCI_DEVICE_ID_REALTEK_8139);