diff --git a/modutils/modutils.c b/modutils/modutils.c
index 0d7d72d8b..8836f7c69 100644
--- a/modutils/modutils.c
+++ b/modutils/modutils.c
@@ -71,7 +71,7 @@ char * FAST_FUNC filename2modname(const char *filename, char *modname)
 	if (modname == NULL)
 		modname = xmalloc(MODULE_NAME_LEN);
 	from = bb_get_last_path_component_nostrip(filename);
-	for (i = 0; i < MODULE_NAME_LEN && from[i] != '\0' && from[i] != '.'; i++)
+	for (i = 0; i < (MODULE_NAME_LEN-1) && from[i] != '\0' && from[i] != '.'; i++)
 		modname[i] = (from[i] == '-') ? '_' : from[i];
 	modname[i] = 0;
 
diff --git a/modutils/modutils.h b/modutils/modutils.h
index 6aaf79daa..cc7c65351 100644
--- a/modutils/modutils.h
+++ b/modutils/modutils.h
@@ -15,8 +15,9 @@
 # pragma GCC visibility push(hidden)
 #endif
 
-/* As defined in linux/include/linux/module.h */
-#define MODULE_NAME_LEN 64
+/* linux/include/linux/module.h has 64, but this is also used
+ * internally for the maximum alias name length, which can be quite long */
+#define MODULE_NAME_LEN 256
 
 const char *moderror(int err) FAST_FUNC;
 llist_t *llist_find(llist_t *first, const char *str) FAST_FUNC;