diff --git a/doc/fcconfig.fncs b/doc/fcconfig.fncs
index 82769d5..e709b54 100644
--- a/doc/fcconfig.fncs
+++ b/doc/fcconfig.fncs
@@ -174,6 +174,10 @@ Returns one of the two sets of fonts from the configuration as specified
 by <parameter>set</parameter>. This font set is owned by the library and must
 not be modified or freed.
 If <parameter>config</parameter> is NULL, the current configuration is used.
+    </para><para>
+This function isn't MT-safe. <function>FcConfigReference</function> must be called
+before using this and then <function>FcConfigDestroy</function> when
+the return value is no longer referenced.
 @@
 
 @RET@           FcBlanks *
@@ -407,6 +411,10 @@ parse error, semantic error or allocation failure. Otherwise returns FcTrue.
 Obtains the system root directory in 'config' if available. All files
 (including file properties in patterns) obtained from this 'config' are
 relative to this system root directory.
+    </para><para>
+This function isn't MT-safe. <function>FcConfigReference</function> must be called
+before using this and then <function>FcConfigDestroy</function> when
+the return value is no longer referenced.
 @SINCE@		2.10.92
 @@
 
@@ -433,6 +441,10 @@ When setting this on the current config this causes changing current config
 @PURPOSE@	Initialize the iterator
 @DESC@
 Initialize 'iter' with the first iterator in the config file information list.
+    </para><para>
+This function isn't MT-safe. <function>FcConfigReference</function> must be called
+before using this and then <function>FcConfigDestroy</function> when the relevant
+values are no longer referenced.
 @SINCE@		2.12.91
 @@
 
@@ -444,6 +456,10 @@ Initialize 'iter' with the first iterator in the config file information list.
 @DESC@
 Set 'iter' to point to the next node in the config file information list.
 If there is no next node, FcFalse is returned.
+    </para><para>
+This function isn't MT-safe. <function>FcConfigReference</function> must be called
+before using <function>FcConfigFileInfoIterInit</function> and then
+<function>FcConfigDestroy</function> when the relevant values are no longer referenced.
 @SINCE@		2.12.91
 @@
 
@@ -459,5 +475,9 @@ If there is no next node, FcFalse is returned.
 Obtain the filename, the description and the flag whether it is enabled or not
 for 'iter' where points to current configuration file information.
 If the iterator is invalid, FcFalse is returned.
+    </para><para>
+This function isn't MT-safe. <function>FcConfigReference</function> must be called
+before using <function>FcConfigFileInfoIterInit</function> and then
+<function>FcConfigDestroy</function> when the relevant values are no longer referenced.
 @SINCE@		2.12.91
 @@
diff --git a/fontconfig/fontconfig.h b/fontconfig/fontconfig.h
index 2f0e8cf..c795245 100644
--- a/fontconfig/fontconfig.h
+++ b/fontconfig/fontconfig.h
@@ -375,7 +375,7 @@ FcPublic FcBool
 FcDirCacheClean (const FcChar8 *cache_dir, FcBool verbose);
 
 FcPublic void
-FcCacheCreateTagFile (const FcConfig *config);
+FcCacheCreateTagFile (FcConfig *config);
 
 FcPublic FcBool
 FcDirCacheCreateUUID (FcChar8  *dir,
@@ -437,7 +437,7 @@ FcPublic FcBlanks *
 FcConfigGetBlanks (FcConfig *config);
 
 FcPublic FcStrList *
-FcConfigGetCacheDirs (const FcConfig	*config);
+FcConfigGetCacheDirs (FcConfig	*config);
 
 FcPublic int
 FcConfigGetRescanInterval (FcConfig *config);
diff --git a/src/fccache.c b/src/fccache.c
index c565560..d8f1dab 100644
--- a/src/fccache.c
+++ b/src/fccache.c
@@ -58,11 +58,15 @@ FcDirCacheDeleteUUID (const FcChar8  *dir,
 {
     FcBool ret = FcTrue;
 #ifndef _WIN32
-    const FcChar8 *sysroot = FcConfigGetSysRoot (config);
+    const FcChar8 *sysroot;
     FcChar8 *target, *d;
     struct stat statb;
     struct timeval times[2];
 
+    config = FcConfigReference (config);
+    if (!config)
+	return FcFalse;
+    sysroot = FcConfigGetSysRoot (config);
     if (sysroot)
 	d = FcStrBuildFilename (sysroot, dir, NULL);
     else
@@ -94,6 +98,7 @@ FcDirCacheDeleteUUID (const FcChar8  *dir,
 bail:
     FcStrFree (d);
 #endif
+    FcConfigDestroy (config);
 
     return ret;
 }
@@ -265,7 +270,13 @@ FcDirCacheUnlink (const FcChar8 *dir, FcConfig *config)
 #endif
     FcStrList	*list;
     FcChar8	*cache_dir;
-    const FcChar8 *sysroot = FcConfigGetSysRoot (config);
+    const FcChar8 *sysroot;
+    FcBool	ret = FcTrue;
+
+    config = FcConfigReference (config);
+    if (!config)
+	return FcFalse;
+    sysroot = FcConfigGetSysRoot (config);
 
     FcDirCacheBasenameMD5 (config, dir, cache_base);
 #ifndef _WIN32
@@ -274,7 +285,10 @@ FcDirCacheUnlink (const FcChar8 *dir, FcConfig *config)
 
     list = FcStrListCreate (config->cacheDirs);
     if (!list)
-        return FcFalse;
+    {
+	ret = FcFalse;
+	goto bail;
+    }
 	
     while ((cache_dir = FcStrListNext (list)))
     {
@@ -304,8 +318,11 @@ FcDirCacheUnlink (const FcChar8 *dir, FcConfig *config)
     FcDirCacheDeleteUUID (dir, config);
     /* return FcFalse if something went wrong */
     if (cache_dir)
-	return FcFalse;
-    return FcTrue;
+	ret = FcFalse;
+bail:
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 static int
@@ -1041,10 +1058,15 @@ FcDirCacheLoad (const FcChar8 *dir, FcConfig *config, FcChar8 **cache_file)
 {
     FcCache *cache = NULL;
 
+    config = FcConfigReference (config);
+    if (!config)
+	return NULL;
     if (!FcDirCacheProcess (config, dir,
 			    FcDirCacheMapHelper,
 			    &cache, cache_file))
-	return NULL;
+	cache = NULL;
+
+    FcConfigDestroy (config);
 
     return cache;
 }
@@ -1055,13 +1077,16 @@ FcDirCacheLoadFile (const FcChar8 *cache_file, struct stat *file_stat)
     int	fd;
     FcCache *cache;
     struct stat	my_file_stat;
+    FcConfig *config;
 
     if (!file_stat)
 	file_stat = &my_file_stat;
     fd = FcDirCacheOpenFile (cache_file, file_stat);
     if (fd < 0)
 	return NULL;
-    cache = FcDirCacheMapFd (FcConfigGetCurrent (), fd, file_stat, NULL);
+    config = FcConfigReference (NULL);
+    cache = FcDirCacheMapFd (config, fd, file_stat, NULL);
+    FcConfigDestroy (config);
     close (fd);
     return cache;
 }
@@ -1155,12 +1180,16 @@ FcBool
 FcDirCacheValid (const FcChar8 *dir)
 {
     FcConfig	*config;
+    FcBool	ret;
 
-    config = FcConfigGetCurrent ();
+    config = FcConfigReference (NULL);
     if (!config)
         return FcFalse;
 
-    return FcDirCacheValidConfig (dir, config);
+    ret = FcDirCacheValidConfig (dir, config);
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 /*
@@ -1438,9 +1467,13 @@ FcDirCacheClean (const FcChar8 *cache_dir, FcBool verbose)
     FcCache	*cache;
     struct stat	target_stat;
     const FcChar8 *sysroot;
+    FcConfig	*config;
 
+    config = FcConfigReference (NULL);
+    if (!config)
+	return FcFalse;
     /* FIXME: this API needs to support non-current FcConfig */
-    sysroot = FcConfigGetSysRoot (NULL);
+    sysroot = FcConfigGetSysRoot (config);
     if (sysroot)
 	dir = FcStrBuildFilename (sysroot, cache_dir, NULL);
     else
@@ -1448,7 +1481,8 @@ FcDirCacheClean (const FcChar8 *cache_dir, FcBool verbose)
     if (!dir)
     {
 	fprintf (stderr, "Fontconfig error: %s: out of memory\n", cache_dir);
-	return FcFalse;
+	ret = FcFalse;
+	goto bail;
     }
     if (access ((char *) dir, W_OK) != 0)
     {
@@ -1525,8 +1559,10 @@ FcDirCacheClean (const FcChar8 *cache_dir, FcBool verbose)
     }
 
     closedir (d);
-  bail0:
+bail0:
     FcStrFree (dir);
+bail:
+    FcConfigDestroy (config);
 
     return ret;
 }
@@ -1968,15 +2004,20 @@ FcDirCacheCreateTagFile (const FcChar8 *cache_dir)
 }
 
 void
-FcCacheCreateTagFile (const FcConfig *config)
+FcCacheCreateTagFile (FcConfig *config)
 {
     FcChar8   *cache_dir = NULL, *d = NULL;
     FcStrList *list;
-    const FcChar8 *sysroot = FcConfigGetSysRoot (config);
+    const FcChar8 *sysroot;
+
+    config = FcConfigReference (config);
+    if (!config)
+	return;
+    sysroot = FcConfigGetSysRoot (config);
 
     list = FcConfigGetCacheDirs (config);
     if (!list)
-	return;
+	goto bail;
 
     while ((cache_dir = FcStrListNext (list)))
     {
@@ -1992,6 +2033,8 @@ FcCacheCreateTagFile (const FcConfig *config)
     if (d)
 	FcStrFree (d);
     FcStrListDone (list);
+bail:
+    FcConfigDestroy (config);
 }
 
 #define __fccache__
diff --git a/src/fccfg.c b/src/fccfg.c
index 21ccd25..11dc876 100644
--- a/src/fccfg.c
+++ b/src/fccfg.c
@@ -237,12 +237,12 @@ FcConfigUptoDate (FcConfig *config)
 {
     FcFileTime	config_time, config_dir_time, font_time;
     time_t	now = time(0);
+    FcBool	ret = FcTrue;
+
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return FcFalse;
-    }
+	return FcFalse;
+
     config_time = FcConfigNewestFile (config->configFiles);
     config_dir_time = FcConfigNewestFile (config->configDirs);
     font_time = FcConfigNewestFile (config->fontDirs);
@@ -258,13 +258,19 @@ FcConfigUptoDate (FcConfig *config)
 	    fprintf (stderr,
                     "Fontconfig warning: Directory/file mtime in the future. New fonts may not be detected.\n");
 	    config->rescanTime = now;
-	    return FcTrue;
+	    goto bail;
 	}
 	else
-	    return FcFalse;
+	{
+	    ret = FcFalse;
+	    goto bail;
+	}
     }
     config->rescanTime = now;
-    return FcTrue;
+bail:
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 FcExpr *
@@ -291,11 +297,26 @@ FcConfigReference (FcConfig *config)
 {
     if (!config)
     {
-	config = FcConfigGetCurrent ();
+	/* Do not use FcConfigGetCurrent () for the purpose of obtaining current FcConfig here.
+	 * because the reference counter must be increased before setting it to _fcConfig.
+	 */
+    retry:
+	config = fc_atomic_ptr_get (&_fcConfig);
 	if (!config)
-	    return 0;
-    }
+	{
+	    config = FcConfigCreate ();
+	    FcRefInc (&config->ref);
 
+	    config = FcInitLoadOwnConfigAndFonts (config);
+	    if (!fc_atomic_ptr_cmpexch (&_fcConfig, NULL, config))
+	    {
+		FcConfigDestroy (config); /* To decrease the refcount for the above one. */
+		FcConfigDestroy (config); /* To destroy it actualy */
+		goto retry;
+	    }
+	    return config;
+	}
+    }
     FcRefInc (&config->ref);
 
     return config;
@@ -475,25 +496,32 @@ FcBool
 FcConfigBuildFonts (FcConfig *config)
 {
     FcFontSet	    *fonts;
+    FcBool	    ret = FcTrue;
 
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return FcFalse;
-    }
+	return FcFalse;
 	
     fonts = FcFontSetCreate ();
     if (!fonts)
-	return FcFalse;
+    {
+	ret = FcFalse;
+	goto bail;
+    }
 
     FcConfigSetFonts (config, fonts, FcSetSystem);
 
     if (!FcConfigAddDirList (config, FcSetSystem, config->fontDirs))
-	return FcFalse;
+    {
+	ret = FcFalse;
+	goto bail;
+    }
     if (FcDebug () & FC_DBG_FONTSET)
 	FcFontSetPrint (fonts);
-    return FcTrue;
+bail:
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 FcBool
@@ -537,13 +565,15 @@ FcConfigAddConfigDir (FcConfig	    *config,
 FcStrList *
 FcConfigGetConfigDirs (FcConfig   *config)
 {
+    FcStrList *ret;
+
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return 0;
-    }
-    return FcStrListCreate (config->configDirs);
+	return NULL;
+    ret = FcStrListCreate (config->configDirs);
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 FcBool
@@ -579,13 +609,15 @@ FcConfigResetFontDirs (FcConfig *config)
 FcStrList *
 FcConfigGetFontDirs (FcConfig	*config)
 {
+    FcStrList *ret;
+
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return 0;
-    }
-    return FcStrListCreate (config->fontDirs);
+	return NULL;
+    ret = FcStrListCreate (config->fontDirs);
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 static FcBool
@@ -670,15 +702,17 @@ FcConfigAddCacheDir (FcConfig	    *config,
 }
 
 FcStrList *
-FcConfigGetCacheDirs (const FcConfig *config)
+FcConfigGetCacheDirs (FcConfig *config)
 {
+    FcStrList *ret;
+
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return 0;
-    }
-    return FcStrListCreate (config->cacheDirs);
+	return NULL;
+    ret = FcStrListCreate (config->cacheDirs);
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 FcBool
@@ -699,13 +733,15 @@ FcConfigAddConfigFile (FcConfig	    *config,
 FcStrList *
 FcConfigGetConfigFiles (FcConfig    *config)
 {
+    FcStrList *ret;
+
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return 0;
-    }
-    return FcStrListCreate (config->configFiles);
+	return NULL;
+    ret = FcStrListCreate (config->configFiles);
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 FcChar8 *
@@ -784,25 +820,26 @@ FcConfigAddBlank (FcConfig	*config FC_UNUSED,
 int
 FcConfigGetRescanInterval (FcConfig *config)
 {
+    int ret;
+
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return 0;
-    }
-    return config->rescanInterval;
+	return 0;
+    ret = config->rescanInterval;
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 FcBool
 FcConfigSetRescanInterval (FcConfig *config, int rescanInterval)
 {
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return FcFalse;
-    }
+	return FcFalse;
     config->rescanInterval = rescanInterval;
+    FcConfigDestroy (config);
+
     return FcTrue;
 }
 
@@ -1670,15 +1707,13 @@ FcConfigSubstituteWithPat (FcConfig    *config,
     FcBool	    retval = FcTrue;
     FcTest	    **tst = NULL;
 
-    if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return FcFalse;
-    }
-
     if (kind < FcMatchKindBegin || kind >= FcMatchKindEnd)
 	return FcFalse;
+
+    config = FcConfigReference (config);
+    if (!config)
+	return FcFalse;
+
     s = config->subst[kind];
     if (kind == FcMatchPattern)
     {
@@ -1973,6 +2008,7 @@ bail1:
 	free (value);
     if (tst)
 	free (tst);
+    FcConfigDestroy (config);
 
     return retval;
 }
@@ -2290,12 +2326,9 @@ FcConfigGetFilename (FcConfig      *config,
     FcChar8    *file, *dir, **path, **p;
     const FcChar8 *sysroot;
 
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return NULL;
-    }
+	return NULL;
     sysroot = FcConfigGetSysRoot (config);
     if (!url || !*url)
     {
@@ -2306,7 +2339,10 @@ FcConfigGetFilename (FcConfig      *config,
     file = 0;
 
     if (FcStrIsAbsoluteFilename(url))
-	return FcConfigFileExists (sysroot, url);
+    {
+	file = FcConfigFileExists (sysroot, url);
+	goto bail;
+    }
 
     if (*url == '~')
     {
@@ -2330,7 +2366,10 @@ FcConfigGetFilename (FcConfig      *config,
     {
 	path = FcConfigGetPath ();
 	if (!path)
-	    return NULL;
+	{
+	    file = NULL;
+	    goto bail;
+	}
 	for (p = path; *p; p++)
 	{
 	    FcChar8 *s;
@@ -2347,6 +2386,9 @@ FcConfigGetFilename (FcConfig      *config,
 	}
 	FcConfigFreePath (path);
     }
+bail:
+    FcConfigDestroy (config);
+
     return file;
 }
 
@@ -2409,17 +2451,18 @@ FcConfigAppFontAddFile (FcConfig    *config,
     FcStrSet	*subdirs;
     FcStrList	*sublist;
     FcChar8	*subdir;
+    FcBool	ret = FcTrue;
 
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return FcFalse;
-    }
+	return FcFalse;
 
     subdirs = FcStrSetCreateEx (FCSS_GROW_BY_64);
     if (!subdirs)
-	return FcFalse;
+    {
+	ret = FcFalse;
+	goto bail;
+    }
 
     set = FcConfigGetFonts (config, FcSetApplication);
     if (!set)
@@ -2428,7 +2471,8 @@ FcConfigAppFontAddFile (FcConfig    *config,
 	if (!set)
 	{
 	    FcStrSetDestroy (subdirs);
-	    return FcFalse;
+	    ret = FcFalse;
+	    goto bail;
 	}
 	FcConfigSetFonts (config, set, FcSetApplication);
     }
@@ -2436,7 +2480,8 @@ FcConfigAppFontAddFile (FcConfig    *config,
     if (!FcFileScanConfig (set, subdirs, file, config))
     {
 	FcStrSetDestroy (subdirs);
-	return FcFalse;
+	ret = FcFalse;
+	goto bail;
     }
     if ((sublist = FcStrListCreate (subdirs)))
     {
@@ -2447,7 +2492,10 @@ FcConfigAppFontAddFile (FcConfig    *config,
 	FcStrListDone (sublist);
     }
     FcStrSetDestroy (subdirs);
-    return FcTrue;
+bail:
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 FcBool
@@ -2456,17 +2504,18 @@ FcConfigAppFontAddDir (FcConfig	    *config,
 {
     FcFontSet	*set;
     FcStrSet	*dirs;
+    FcBool	ret = FcTrue;
 
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return FcFalse;
-    }
+	return FcFalse;
 
     dirs = FcStrSetCreateEx (FCSS_GROW_BY_64);
     if (!dirs)
-	return FcFalse;
+    {
+	ret = FcFalse;
+	goto bail;
+    }
 
     set = FcConfigGetFonts (config, FcSetApplication);
     if (!set)
@@ -2475,7 +2524,8 @@ FcConfigAppFontAddDir (FcConfig	    *config,
 	if (!set)
 	{
 	    FcStrSetDestroy (dirs);
-	    return FcFalse;
+	    ret = FcFalse;
+	    goto bail;
 	}
 	FcConfigSetFonts (config, set, FcSetApplication);
     }
@@ -2485,23 +2535,26 @@ FcConfigAppFontAddDir (FcConfig	    *config,
     if (!FcConfigAddDirList (config, FcSetApplication, dirs))
     {
 	FcStrSetDestroy (dirs);
-	return FcFalse;
+	ret = FcFalse;
+	goto bail;
     }
     FcStrSetDestroy (dirs);
-    return FcTrue;
+bail:
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 void
 FcConfigAppFontClear (FcConfig	    *config)
 {
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return;
-    }
+	return;
 
     FcConfigSetFonts (config, 0, FcSetApplication);
+
+    FcConfigDestroy (config);
 }
 
 /*
diff --git a/src/fcdir.c b/src/fcdir.c
index 7d7b23c..693c845 100644
--- a/src/fcdir.c
+++ b/src/fcdir.c
@@ -167,7 +167,16 @@ FcFileScan (FcFontSet	    *set,
 	    const FcChar8   *file,
 	    FcBool	    force FC_UNUSED)
 {
-    return FcFileScanConfig (set, dirs, file, FcConfigGetCurrent ());
+    FcConfig *config;
+    FcBool ret;
+
+    config = FcConfigReference (NULL);
+    if (!config)
+	return FcFalse;
+    ret = FcFileScanConfig (set, dirs, file, config);
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 /*
@@ -271,10 +280,19 @@ FcDirScan (FcFontSet	    *set,
 	   const FcChar8    *dir,
 	   FcBool	    force FC_UNUSED)
 {
+    FcConfig *config;
+    FcBool ret;
+
     if (cache || !force)
 	return FcFalse;
 
-    return FcDirScanConfig (set, dirs, dir, force, FcConfigGetCurrent ());
+    config = FcConfigReference (NULL);
+    if (!config)
+	return FcFalse;
+    ret = FcDirScanConfig (set, dirs, dir, force, config);
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 /*
@@ -353,12 +371,16 @@ FcDirCacheRescan (const FcChar8 *dir, FcConfig *config)
     FcCache *new = NULL;
     struct stat dir_stat;
     FcStrSet *dirs;
-    const FcChar8 *sysroot = FcConfigGetSysRoot (config);
+    const FcChar8 *sysroot;
     FcChar8 *d = NULL;
 #ifndef _WIN32
     int fd = -1;
 #endif
 
+    config = FcConfigReference (config);
+    if (!config)
+	return NULL;
+    sysroot = FcConfigGetSysRoot (config);
     cache = FcDirCacheLoad (dir, config, NULL);
     if (!cache)
 	goto bail;
@@ -401,6 +423,7 @@ bail1:
 bail:
     if (d)
 	FcStrFree (d);
+    FcConfigDestroy (config);
 
     return new;
 }
@@ -413,6 +436,7 @@ FcDirCacheRead (const FcChar8 *dir, FcBool force, FcConfig *config)
 {
     FcCache		*cache = NULL;
 
+    config = FcConfigReference (config);
     /* Try to use existing cache file */
     if (!force)
 	cache = FcDirCacheLoad (dir, config, NULL);
@@ -420,6 +444,7 @@ FcDirCacheRead (const FcChar8 *dir, FcBool force, FcConfig *config)
     /* Not using existing cache file, construct new cache */
     if (!cache)
 	cache = FcDirCacheScan (dir, config);
+    FcConfigDestroy (config);
 
     return cache;
 }
diff --git a/src/fcinit.c b/src/fcinit.c
index 5831a19..6f82ebd 100644
--- a/src/fcinit.c
+++ b/src/fcinit.c
@@ -229,7 +229,8 @@ FcInitReinitialize (void)
 FcBool
 FcInitBringUptoDate (void)
 {
-    FcConfig	*config = FcConfigGetCurrent ();
+    FcConfig	*config = FcConfigReference (NULL);
+    FcBool	ret = FcTrue;
     time_t	now;
 
     if (!config)
@@ -238,19 +239,23 @@ FcInitBringUptoDate (void)
      * rescanInterval == 0 disables automatic up to date
      */
     if (config->rescanInterval == 0)
-	return FcTrue;
+	goto bail;
     /*
      * Check no more often than rescanInterval seconds
      */
     now = time (0);
     if (config->rescanTime + config->rescanInterval - now > 0)
-	return FcTrue;
+	goto bail;
     /*
      * If up to date, don't reload configuration
      */
     if (FcConfigUptoDate (0))
-	return FcTrue;
-    return FcInitReinitialize ();
+	goto bail;
+    ret = FcInitReinitialize ();
+bail:
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 #define __fcinit__
diff --git a/src/fclist.c b/src/fclist.c
index 494bdea..053803b 100644
--- a/src/fclist.c
+++ b/src/fclist.c
@@ -491,11 +491,10 @@ FcFontSetList (FcConfig	    *config,
     {
 	if (!FcInitBringUptoDate ())
 	    goto bail0;
-
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    goto bail0;
     }
+    config = FcConfigReference (config);
+    if (!config)
+	goto bail0;
     FcListHashTableInit (&table);
 
     if (!os)
@@ -558,7 +557,7 @@ FcFontSetList (FcConfig	    *config,
      */
     ret = FcFontSetCreate ();
     if (!ret)
-	goto bail0;
+	goto bail1;
     for (i = 0; i < FC_LIST_HASH_SIZE; i++)
 	while ((bucket = table.buckets[i]))
 	{
@@ -570,6 +569,7 @@ FcFontSetList (FcConfig	    *config,
 
     if (destroy_os)
         FcObjectSetDestroy (os);
+    FcConfigDestroy (config);
 
     return ret;
 
@@ -577,6 +577,7 @@ bail2:
     FcFontSetDestroy (ret);
 bail1:
     FcListHashTableCleanup (&table);
+    FcConfigDestroy (config);
 bail0:
     if (destroy_os)
 	FcObjectSetDestroy (os);
@@ -588,24 +589,26 @@ FcFontList (FcConfig	*config,
 	    FcPattern	*p,
 	    FcObjectSet *os)
 {
-    FcFontSet	*sets[2];
+    FcFontSet	*sets[2], *ret;
     int		nsets;
 
     if (!config)
     {
 	if (!FcInitBringUptoDate ())
 	    return 0;
-
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return 0;
     }
+    config = FcConfigReference (config);
+    if (!config)
+	return NULL;
     nsets = 0;
     if (config->fonts[FcSetSystem])
 	sets[nsets++] = config->fonts[FcSetSystem];
     if (config->fonts[FcSetApplication])
 	sets[nsets++] = config->fonts[FcSetApplication];
-    return FcFontSetList (config, sets, nsets, p, os);
+    ret = FcFontSetList (config, sets, nsets, p, os);
+    FcConfigDestroy (config);
+
+    return ret;
 }
 #define __fclist__
 #include "fcaliastail.h"
diff --git a/src/fcmatch.c b/src/fcmatch.c
index 78bcf7b..3bc352b 100644
--- a/src/fcmatch.c
+++ b/src/fcmatch.c
@@ -845,7 +845,7 @@ FcFontSetMatch (FcConfig    *config,
 		FcPattern   *p,
 		FcResult    *result)
 {
-    FcPattern	    *best;
+    FcPattern	    *best, *ret = NULL;
 
     assert (sets != NULL);
     assert (p != NULL);
@@ -853,17 +853,16 @@ FcFontSetMatch (FcConfig    *config,
 
     *result = FcResultNoMatch;
 
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return 0;
-    }
+	    return NULL;
     best = FcFontSetMatchInternal (sets, nsets, p, result);
     if (best)
-	return FcFontRenderPrepare (config, p, best);
-    else
-	return NULL;
+	ret = FcFontRenderPrepare (config, p, best);
+
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 FcPattern *
@@ -873,19 +872,16 @@ FcFontMatch (FcConfig	*config,
 {
     FcFontSet	*sets[2];
     int		nsets;
-    FcPattern   *best;
+    FcPattern   *best, *ret = NULL;
 
     assert (p != NULL);
     assert (result != NULL);
 
     *result = FcResultNoMatch;
 
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return 0;
-    }
+	return NULL;
     nsets = 0;
     if (config->fonts[FcSetSystem])
 	sets[nsets++] = config->fonts[FcSetSystem];
@@ -894,9 +890,11 @@ FcFontMatch (FcConfig	*config,
 
     best = FcFontSetMatchInternal (sets, nsets, p, result);
     if (best)
-	return FcFontRenderPrepare (config, p, best);
-    else
-	return NULL;
+	ret = FcFontRenderPrepare (config, p, best);
+
+    FcConfigDestroy (config);
+
+    return ret;
 }
 
 typedef struct _FcSortNode {
@@ -1183,7 +1181,7 @@ FcFontSort (FcConfig	*config,
 	    FcCharSet	**csp,
 	    FcResult	*result)
 {
-    FcFontSet	*sets[2];
+    FcFontSet	*sets[2], *ret;
     int		nsets;
 
     assert (p != NULL);
@@ -1191,18 +1189,18 @@ FcFontSort (FcConfig	*config,
 
     *result = FcResultNoMatch;
 
+    config = FcConfigReference (config);
     if (!config)
-    {
-	config = FcConfigGetCurrent ();
-	if (!config)
-	    return 0;
-    }
+	return NULL;
     nsets = 0;
     if (config->fonts[FcSetSystem])
 	sets[nsets++] = config->fonts[FcSetSystem];
     if (config->fonts[FcSetApplication])
 	sets[nsets++] = config->fonts[FcSetApplication];
-    return FcFontSetSort (config, sets, nsets, p, trim, csp, result);
+    ret = FcFontSetSort (config, sets, nsets, p, trim, csp, result);
+    FcConfigDestroy (config);
+
+    return ret;
 }
 #define __fcmatch__
 #include "fcaliastail.h"
diff --git a/test/Makefile.am b/test/Makefile.am
index e44aa0b..aae45cb 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -42,6 +42,11 @@ test_pthread_LDADD = $(top_builddir)/src/libfontconfig.la
 # We don't enable this test by default because it will require config and fonts
 # to meaningfully test anything, and we are not installed yet.
 #TESTS += test-pthread
+
+check_PROGRAMS += test-crbug1004254
+test_crbug1004254_LDADD = $(top_builddir)/src/libfontconfig.la
+# Disabling this for the same reason as above but trying to run in run-test.sh.
+#TESTS += test-crbug1004254
 endif
 check_PROGRAMS += test-bz89617
 test_bz89617_CFLAGS = \
diff --git a/test/run-test.sh b/test/run-test.sh
index 8ad09e3..e1ee6d0 100644
--- a/test/run-test.sh
+++ b/test/run-test.sh
@@ -20,6 +20,8 @@
 # DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 # TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 # PERFORMANCE OF THIS SOFTWARE.
+set -e
+
 case "$OSTYPE" in
     msys ) MyPWD=`pwd -W` ;;  # On Msys/MinGW, returns a MS Windows style path.
     *    ) MyPWD=`pwd`    ;;  # On any other platforms, returns a Unix style path.
@@ -408,4 +410,17 @@ rm -rf $MYCACHEBASEDIR $MYCONFIG my-fonts.conf my-out my-out.expected
 
 fi # if [ "x$EXEEXT" = "x" ]
 
+if [ -x $BUILDTESTDIR/test-crbug1004254 ]; then
+    dotest "MT-safe global config"
+    prep
+    curl -s -o $FONTDIR/noto.zip https://noto-website-2.storage.googleapis.com/pkgs/NotoSans-hinted.zip
+    (cd $FONTDIR; unzip noto.zip)
+    if [ -n ${SOURCE_DATE_EPOCH:-} ] && [ ${#SOURCE_DATE_EPOCH} -gt 0 ]; then
+	touch -m -t "`date -d \"@${SOURCE_DATE_EPOCH}\" +%y%m%d%H%M.%S`" $FONTDIR
+    fi
+    $BUILDTESTDIR/test-crbug1004254
+else
+    echo "No test-crbug1004254: skipped"
+fi
+
 rm -rf $FONTDIR $CACHEFILE $CACHEDIR $BASEDIR $FONTCONFIG_FILE out
diff --git a/test/test-crbug1004254.c b/test/test-crbug1004254.c
new file mode 100644
index 0000000..1cc6fc7
--- /dev/null
+++ b/test/test-crbug1004254.c
@@ -0,0 +1,116 @@
+/*
+ * fontconfig/test/test-pthread.c
+ *
+ * Copyright © 2000 Keith Packard
+ * Copyright © 2013 Raimund Steger
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of the author(s) not be used in
+ * advertising or publicity pertaining to distribution of the software without
+ * specific, written prior permission.  The authors make no
+ * representations about the suitability of this software for any purpose.  It
+ * is provided "as is" without express or implied warranty.
+ *
+ * THE AUTHOR(S) DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <pthread.h>
+#include <fontconfig/fontconfig.h>
+
+struct thr_arg_s
+{
+    int thr_num;
+};
+
+static void
+run_query (void)
+{
+    FcPattern *pat = FcPatternCreate (), *match;
+    FcResult result;
+
+    FcPatternAddString (pat, FC_FAMILY, "sans-serif");
+    FcPatternAddBool (pat, FC_SCALABLE, FcTrue);
+    FcConfigSubstitute (NULL, pat, FcMatchPattern);
+    FcDefaultSubstitute (pat);
+    match = FcFontMatch (NULL, pat, &result);
+    if (result != FcResultMatch || !match)
+    {
+	fprintf (stderr, "ERROR: No matches found\n");
+    }
+    if (match)
+	FcPatternDestroy (match);
+    FcPatternDestroy (pat);
+}
+
+static void
+run_reinit (void)
+{
+    if (!FcInitReinitialize ())
+    {
+	fprintf (stderr, "ERROR: Reinitializing failed\n");
+    }
+}
+
+#define NTEST 3000
+
+static void *
+run_test_in_thread (void *arg)
+{
+    struct thr_arg_s *thr_arg = (struct thr_arg_s *) arg;
+    int thread_num = thr_arg->thr_num;
+
+    fprintf (stderr, "Worker %d: started (round %d)\n", thread_num % 2, thread_num / 2);
+    if ((thread_num % 2) == 0)
+    {
+	run_query ();
+    }
+    else
+    {
+	run_reinit ();
+    }
+    fprintf (stderr, "Worker %d: done (round %d)\n", thread_num % 2, thread_num / 2);
+
+    return NULL;
+}
+
+int
+main (int argc, char **argv)
+{
+    pthread_t threads[NTEST];
+    struct thr_arg_s thr_arg[NTEST];
+    int i, j;
+
+    for (i = 0; i < NTEST; i++)
+    {
+	int result;
+
+	fprintf (stderr, "Thread %d (worker %d round %d): creating\n", i, i % 2, i / 2);
+	thr_arg[i].thr_num = i;
+	result = pthread_create (&threads[i], NULL, run_test_in_thread,
+				 (void *) &thr_arg[i]);
+	if (result != 0)
+	{
+	    fprintf (stderr, "Cannot create thread %d\n", i);
+	    break;
+	}
+    }
+    for (j = 0; j < i; j++)
+    {
+	pthread_join(threads[j], NULL);
+	fprintf (stderr, "Joined thread %d\n", j);
+    }
+    FcFini ();
+
+    return 0;
+}
-- 
2.24.1
 
From aa8c8cfa9fb2563482336249e3f56459099fcf6e Mon Sep 17 00:00:00 2001
From: Akira TAGOH <akira@tagoh.org>
Date: Sat, 2 Nov 2019 00:14:48 +0900
Subject: [PATCH 4/9] Fix potential race condition in FcConfigSetCurrent and
 FcConfigReference
 
---
 src/fccache.c |   2 +
 src/fccfg.c   | 105 ++++++++++++++++++++++++++++++++++++++++++--------
 2 files changed, 90 insertions(+), 17 deletions(-)
 
diff --git a/src/fccache.c b/src/fccache.c
index d8f1dab..4744a84 100644
--- a/src/fccache.c
+++ b/src/fccache.c
@@ -1085,6 +1085,8 @@ FcDirCacheLoadFile (const FcChar8 *cache_file, struct stat *file_stat)
     if (fd < 0)
 	return NULL;
     config = FcConfigReference (NULL);
+    if (!config)
+	return NULL;
     cache = FcDirCacheMapFd (config, fd, file_stat, NULL);
     FcConfigDestroy (config);
     close (fd);
diff --git a/src/fccfg.c b/src/fccfg.c
index 11dc876..30f37af 100644
--- a/src/fccfg.c
+++ b/src/fccfg.c
@@ -33,6 +33,49 @@
 #endif
 
 static FcConfig    *_fcConfig; /* MT-safe */
+static FcMutex	   *_lock;
+
+static void
+lock_config (void)
+{
+    FcMutex *lock;
+retry:
+    lock = fc_atomic_ptr_get (&_lock);
+    if (!lock)
+    {
+	lock = (FcMutex *) malloc (sizeof (FcMutex));
+	FcMutexInit (lock);
+	if (!fc_atomic_ptr_cmpexch (&_lock, NULL, lock))
+	{
+	    FcMutexFinish (lock);
+	    goto retry;
+	}
+	FcMutexLock (lock);
+	/* Initialize random state */
+	FcRandom ();
+	return;
+    }
+    FcMutexLock (lock);
+}
+
+static void
+unlock_config (void)
+{
+    FcMutexUnlock (_lock);
+}
+
+static void
+free_lock (void)
+{
+    FcMutex *lock;
+
+    lock = fc_atomic_ptr_get (&_lock);
+    if (lock && fc_atomic_ptr_cmpexch (&_lock, lock, NULL))
+    {
+	FcMutexFinish (lock);
+	free (lock);
+    }
+}
 
 static FcConfig *
 FcConfigEnsure (void)
@@ -44,8 +87,9 @@ retry:
     {
 	config = FcInitLoadConfigAndFonts ();
 
-	if (!fc_atomic_ptr_cmpexch (&_fcConfig, NULL, config)) {
-	    FcConfigDestroy (config);
+	if (!config || !fc_atomic_ptr_cmpexch (&_fcConfig, NULL, config)) {
+	    if (config)
+		FcConfigDestroy (config);
 	    goto retry;
 	}
     }
@@ -76,6 +120,7 @@ FcConfigFini (void)
     FcConfig *cfg = fc_atomic_ptr_get (&_fcConfig);
     if (cfg && fc_atomic_ptr_cmpexch (&_fcConfig, cfg, NULL))
 	FcConfigDestroy (cfg);
+    free_lock ();
 }
 
 static FcChar8 *
@@ -297,27 +342,31 @@ FcConfigReference (FcConfig *config)
 {
     if (!config)
     {
-	/* Do not use FcConfigGetCurrent () for the purpose of obtaining current FcConfig here.
-	 * because the reference counter must be increased before setting it to _fcConfig.
+	/* lock during obtaining the value from _fcConfig and count up refcount there,
+	 * there are the race between them.
 	 */
+	lock_config ();
     retry:
 	config = fc_atomic_ptr_get (&_fcConfig);
 	if (!config)
 	{
-	    config = FcConfigCreate ();
-	    FcRefInc (&config->ref);
+	    unlock_config ();
 
-	    config = FcInitLoadOwnConfigAndFonts (config);
+	    config = FcInitLoadConfigAndFonts ();
+	    if (!config)
+		goto retry;
+	    lock_config ();
 	    if (!fc_atomic_ptr_cmpexch (&_fcConfig, NULL, config))
 	    {
-		FcConfigDestroy (config); /* To decrease the refcount for the above one. */
-		FcConfigDestroy (config); /* To destroy it actualy */
+		FcConfigDestroy (config);
 		goto retry;
 	    }
-	    return config;
 	}
+	FcRefInc (&config->ref);
+	unlock_config ();
     }
-    FcRefInc (&config->ref);
+    else
+	FcRefInc (&config->ref);
 
     return config;
 }
@@ -529,20 +578,29 @@ FcConfigSetCurrent (FcConfig *config)
 {
     FcConfig *cfg;
 
+    if (config)
+    {
+	if (!config->fonts[FcSetSystem])
+	    if (!FcConfigBuildFonts (config))
+		return FcFalse;
+	FcRefInc (&config->ref);
+    }
+
+    lock_config ();
 retry:
     cfg = fc_atomic_ptr_get (&_fcConfig);
 
     if (config == cfg)
+    {
+	unlock_config ();
+	if (config)
+	    FcConfigDestroy (config);
 	return FcTrue;
-
-    if (config && !config->fonts[FcSetSystem])
-	if (!FcConfigBuildFonts (config))
-	    return FcFalse;
+    }
 
     if (!fc_atomic_ptr_cmpexch (&_fcConfig, cfg, config))
 	goto retry;
-
-    FcConfigReference (config);
+    unlock_config ();
     if (cfg)
 	FcConfigDestroy (cfg);
 
@@ -2649,7 +2707,9 @@ FcConfigSetSysRoot (FcConfig      *config,
 {
     FcChar8 *s = NULL;
     FcBool init = FcFalse;
+    int nretry = 3;
 
+retry:
     if (!config)
     {
 	/* We can't use FcConfigGetCurrent() here to ensure
@@ -2681,6 +2741,17 @@ FcConfigSetSysRoot (FcConfig      *config,
     if (init)
     {
 	config = FcInitLoadOwnConfigAndFonts (config);
+	if (!config)
+	{
+	    /* Something failed. this is usually unlikely. so retrying */
+	    init = FcFalse;
+	    if (--nretry == 0)
+	    {
+		fprintf (stderr, "Fontconfig warning: Unable to initialize config and retry limit exceeded. sysroot functionality may not work as expected.\n");
+		return;
+	    }
+	    goto retry;
+	}
 	FcConfigSetCurrent (config);
 	/* FcConfigSetCurrent() increases the refcount.
 	 * decrease it here to avoid the memory leak.
-- 
2.24.1
