diff -up texinfo-6.4/info/nodes.c.orig texinfo-6.4/info/nodes.c

--- texinfo-6.4/info/nodes.c.orig	2017-06-18 14:50:42.000000000 +0200

+++ texinfo-6.4/info/nodes.c	2017-07-10 09:39:10.195209219 +0200

@@ -678,6 +678,7 @@ info_find_subfile (char *fullpath)

   char *with_extension = 0;

   int i;

   FILE_BUFFER *file_buffer = 0;

+  int fullpath_len = strlen (fullpath);

   /* First try to find the file in our list of already loaded files. */

   if (info_loaded_files)

@@ -685,7 +686,9 @@ info_find_subfile (char *fullpath)

       for (i = 0; (file_buffer = info_loaded_files[i]); i++)

         /* Check if fullpath starts the name of the recorded file (extra

            extensions like ".info.gz" could be added.) */

-        if (!strncmp (file_buffer->fullpath, fullpath, strlen (fullpath)))

+        if (!strncmp (file_buffer->fullpath, fullpath, fullpath_len)

+            && (file_buffer->fullpath[fullpath_len] == '\0'

+                || file_buffer->fullpath[fullpath_len] == '.'))

           {

             struct stat new_info, *old_info;