1730 DTrace should ignore type information from modules with cth_parlabel mismatches
Reviewed by: Keith Wesolowski <keith.wesolowski@joyent.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>

*** 1655,1664 ****
--- 1655,1674 ----
                          goto err;
  
                  if ((pfp = ctf_modopen(mod->mod_mp, &error)) == NULL)
                          goto err;
  
+                 /*
+                  * If the parent module does not have the label we expect,
+                  * ignore it and fail to avoid presenting non-sensical data.
+                  */
+                 if (ctf_label_info(pfp, ctf_parent_label(fp),
+                     NULL) == CTF_ERR) {
+                         ctf_close(pfp);
+                         goto err;
+                 }
+ 
                  if (ctf_import(fp, pfp) != 0) {
                          ctf_close(pfp);
                          goto err;
                  }