diff --git a/ChangeLog b/ChangeLog
index 8a715ee813..1414882de1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed May  1 21:11:17 2013  Tanaka Akira  <akr@fsij.org>
+
+	* time.c (localtime_with_gmtoff_zone): musl libc may return NULL for
+	  tm_zone.
+
 Wed May  1 18:59:36 2013  Benoit Daloze  <eregontp@gmail.com>
 
 	* enum.c (Enumerable#chunk): fix grammar of error message
diff --git a/time.c b/time.c
index e9f59c7353..6b457f22ff 100644
--- a/time.c
+++ b/time.c
@@ -1697,7 +1697,10 @@ localtime_with_gmtoff_zone(const time_t *t, struct tm *result, long *gmtoff, con
 
         if (zone) {
 #if defined(HAVE_TM_ZONE)
-            *zone = zone_str(tm.tm_zone);
+            if (tm.tm_zone)
+                *zone = zone_str(tm.tm_zone);
+            else
+                *zone = zone_str("(NO-TIMEZONE-ABBREVIATION)");
 #elif defined(HAVE_TZNAME) && defined(HAVE_DAYLIGHT)
             /* this needs tzset or localtime, instead of localtime_r */
             *zone = zone_str(tzname[daylight && tm.tm_isdst]);