A Suspected double-free vulnerability

[p611148aadsl]

hello, During a static audit, a suspected double-free vulnerability was discovered
in funtion SLPDRegFileReadSrvReg of openslp/slpd/slpd_regfile.c

else
         {
            char * tmp_attrlist;
            attrlistlen += strlen(slider1) + 3;
            if ((tmp_attrlist = xrealloc(attrlist, attrlistlen + 1)) == 0)
            {
               xfree(attrlist);
               result = SLP_ERROR_INTERNAL_ERROR;
               goto CLEANUP;
            }
            attrlist = tmp_attrlist;
            strcat(attrlist, ",");
         }

it will xfree attrlist when xrealloc failed and it will be freed again when CLEANUP

CLEANUP:

   /* check for errors and free memory */
   switch(result)
   {
      case SLP_ERROR_INTERNAL_ERROR:
         SLPDLog("\nERROR: Out of memory one reg file line:\n   %s\n", line);
         break;

      case SLP_ERROR_INVALID_REGISTRATION:
         SLPDLog("\nERROR: Invalid reg file format near:\n   %s\n", line);
         break;

      case SLP_ERROR_SCOPE_NOT_SUPPORTED:
         SLPDLog("\nERROR: Duplicate scopes or scope list with "
               "embedded spaces near:\n   %s\n", line);
         break;

      default:
         break;
   }

   xfree(langtag);
   xfree(scopelist);
   xfree(url);
   xfree(srvtype);
   xfree(attrlist);

I compiled this project without DEBUG.

#else    /* ?DEBUG */

void * slp_xmemdup(const void * ptr, size_t srclen);

#define xmalloc   malloc
#define xcalloc   calloc
#define xrealloc  realloc
#define xfree     free
#define xstrdup   strdup
#define xmemdup   slp_xmemdup

#endif   /* ?DEBUG */

is it a bug?