diff --git a/ChangeLog b/ChangeLog
index 282140a37f..53ae4e5826 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -44,3 +44,7 @@
 
         * Add eina_barrier API to cover pthread_barrier functionality
         * Add eina_tmpstr_add() and eina_tmpstr_del().
+
+2012-10-19  Patryk Kaczmarek
+
+	* eina_stringshare_add_length return NULL when func args are wrong.
diff --git a/configure.ac b/configure.ac
index d49f167162..e2bfb98da2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -361,8 +361,8 @@ case "$build_profile" in
      with_max_log_level=""
      have_stringshare_usage="yes"
      want_valgrind="no" # TODO: "yes" is not working: relocation R_X86_64_32S against `vgPlain_interim_stack' can not be used when making a shared object; recompile with -fPIC
-     want_debug_malloc="yes"
-     want_debug_threads="yes"
+     want_debug_malloc="no"
+     want_debug_threads="no"
      ;;
 
    release)
diff --git a/src/lib/eina/eina_stringshare.c b/src/lib/eina/eina_stringshare.c
index 0e6421458a..6d236c53c0 100644
--- a/src/lib/eina/eina_stringshare.c
+++ b/src/lib/eina/eina_stringshare.c
@@ -612,7 +612,7 @@ EAPI Eina_Stringshare *
 eina_stringshare_add_length(const char *str, unsigned int slen)
 {
    if ((!str) || (slen <= 0))
-     return "";
+     return NULL;
    else if (slen == 1)
      return (Eina_Stringshare *) _eina_stringshare_single + ((*str) << 1);
    else if (slen < 4)