2 files changed, 10 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog
index a19c17f6c3..18133b3642 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Jan 29 06:40:02 2016  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* thread.c (rb_thread_inspect): display @wait_for field if the
+	  target thread is waiting for a mutex.
+
 Thu Jan 28 01:01:20 2016  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* thread.c (rb_thread_inspect): make human readable.
diff --git a/thread.c b/thread.c
index 8d078e7443..f61db9e931 100644
--- a/thread.c
+++ b/thread.c
@@ -2833,7 +2833,11 @@ rb_thread_inspect(VALUE thread)
 	    rb_gc_force_recycle(loc);
 	}
     }
-    rb_str_catf(str, ", @status=%s>", status);
+    rb_str_catf(str, ", @status=%s", status);
+    if (th->locking_mutex != Qfalse) {
+	rb_str_catf(str, ", @wait_for=%"PRIsVALUE, rb_inspect(th->locking_mutex));
+    }
+    rb_str_catf(str, ">");
     OBJ_INFECT(str, thread);
 
     return str;