diff --git a/devicemodel/hw/pci/virtio/virtio_net.c b/devicemodel/hw/pci/virtio/virtio_net.c
index 563443d2b..39aee41cb 100644
--- a/devicemodel/hw/pci/virtio/virtio_net.c
+++ b/devicemodel/hw/pci/virtio/virtio_net.c
@@ -850,14 +850,14 @@ virtio_net_init(struct vmctx *ctx, struct pci_vdev *dev, char *opts)
 	unsigned char digest[16];
 	char nstr[80];
 	char tname[MAXCOMLEN + 1];
-	struct virtio_net *net;
+	struct virtio_net *net = NULL;
 	char *devopts = NULL;
 	char *name = NULL;
 	char *type = NULL;
 	char *mac_seed = NULL;
-	char *tmp;
-	char *vtopts;
-	char *opt;
+	char *tmp = NULL;
+	char *vtopts = NULL;
+	char *opt = NULL;
 	int mac_provided;
 	pthread_mutexattr_t attr;
 	int rc;
@@ -940,8 +940,11 @@ virtio_net_init(struct vmctx *ctx, struct pci_vdev *dev, char *opts)
 		return -1;
 	}
 
-	vtopts = tmp = strdup(opts);
-	if (strncmp(tmp, "tap", 3) == 0) {
+	if (opts != NULL) {
+		vtopts = tmp = strdup(opts);
+	}
+
+	if ((tmp != NULL) && (strncmp(tmp, "tap", 3) == 0)) {
 		type = strsep(&tmp, "=");
 		name = strsep(&tmp, ",");
 	}
@@ -963,8 +966,13 @@ virtio_net_init(struct vmctx *ctx, struct pci_vdev *dev, char *opts)
 	 * followed by an MD5 of the PCI slot/func number and dev name
 	 */
 	if (!mac_provided) {
-		snprintf(nstr, sizeof(nstr), "%d-%d-%s", dev->slot,
-		    dev->func, mac_seed);
+		if (mac_seed != NULL) {
+			snprintf(nstr, sizeof(nstr), "%d-%d-%s", dev->slot,
+				dev->func, mac_seed);
+		} else {
+			snprintf(nstr, sizeof(nstr), "%d-%d", dev->slot,
+				dev->func);
+		}
 #if OPENSSL_VERSION_NUMBER >= 0x30000000L
 		EVP_MD_CTX *mdctx = EVP_MD_CTX_new();
 		EVP_DigestInit_ex(mdctx, EVP_md5(), NULL);
diff --git a/devicemodel/hw/platform/tpm/tpm.c b/devicemodel/hw/platform/tpm/tpm.c
index e8f15b210..0277f6537 100644
--- a/devicemodel/hw/platform/tpm/tpm.c
+++ b/devicemodel/hw/platform/tpm/tpm.c
@@ -108,7 +108,7 @@ static int init_tpm2_pt(char *opts, struct mmio_dev *tpm2dev)
 	uint64_t tpm2_buffer_hpa, tpm2_buffer_size;
 	uint32_t base = 0;
 	struct acpi_table_tpm2 tpm2 = { 0 };
-	char *devopts, *vtopts;
+	char *devopts, *vtopts = NULL;
 
 	/* TODO: Currently we did not validate if the opts is a valid one.
 	 * We trust it to be valid as specifying --acpidev_pt is regarded
@@ -119,7 +119,9 @@ static int init_tpm2_pt(char *opts, struct mmio_dev *tpm2dev)
 	}
 
 	devopts = strdup(opts);
-	vtopts = strstr(devopts,",");
+	if (devopts != NULL) {
+		vtopts = strstr(devopts,",");
+	}
 
 	/* Check whether user set the uid to identify same hid devices for
 	 * several instances.
@@ -129,7 +131,7 @@ static int init_tpm2_pt(char *opts, struct mmio_dev *tpm2dev)
 	}
 
 	/* parse /proc/iomem to find the address and size of tpm buffer */
-	if (!get_mmio_hpa_resource(devopts, &tpm2_buffer_hpa, &tpm2_buffer_size)) {
+	if ((devopts != NULL) && (!get_mmio_hpa_resource(devopts, &tpm2_buffer_hpa, &tpm2_buffer_size))) {
 		free(devopts);
 		return -ENODEV;
 	}