diff --git a/ChangeLog b/ChangeLog
index 7eaf6b2d11..4913635e1a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Tue Jan 21 16:26:44 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* thread_pthread.c (rb_thread_create_timer_thread): expand timer
+	  thread stack size to get rid of segfault on FreeBSD/powerpc64.
+	  based on the patch by Steve Wills at [ruby-core:59923].
+	  [ruby-core:56590] [Bug #8783]
+
 Tue Jan 21 04:31:23 2014  Tanaka Akira  <akr@fsij.org>
 
 	* ext/socket/option.c: Use "int" for IP_MULTICAST_LOOP and
diff --git a/thread_pthread.c b/thread_pthread.c
index 76f033771c..36fa73cd94 100644
--- a/thread_pthread.c
+++ b/thread_pthread.c
@@ -1480,9 +1480,9 @@ rb_thread_create_timer_thread(void)
         }
 # ifdef PTHREAD_STACK_MIN
 	{
-#   define TIMER_THREAD_STACK_MIN_SIZE (4096 * 3)
+#   define TIMER_THREAD_STACK_MIN_SIZE (4096 * 4)
 	    /* Allocate the machine stack for the timer thread
-	     * at least 12KB (3 pages).  FreeBSD 8.2 AMD64 causes
+	     * at least 16KB (4 pages).  FreeBSD 8.2 AMD64 causes
 	     * machine stack overflow only with PTHREAD_STACK_MIN.
 	     */
 #   if TIMER_THREAD_STACK_MIN_SIZE < PTHREAD_STACK_MIN