diff --git a/usr.sbin/pciconf/pciconf.c b/usr.sbin/pciconf/pciconf.c
index bfbcf742e84..d5e646a300f 100644
--- a/usr.sbin/pciconf/pciconf.c
+++ b/usr.sbin/pciconf/pciconf.c
@@ -879,7 +879,8 @@ getdevice(const char *name)
 		errx(1, "Device name is too long");
 	memcpy(patterns[0].pd_name, name, cp - name);
 	patterns[0].pd_unit = strtol(cp, &cp, 10);
-	assert(*cp == '\0');
+	if (*cp != '\0')
+		errx(1, "Invalid device name");
 	patterns[0].flags = PCI_GETCONF_MATCH_NAME | PCI_GETCONF_MATCH_UNIT;
 	pc.num_patterns = 1;
 	pc.pat_buf_len = sizeof(patterns);