diff --git a/ChangeLog b/ChangeLog
index 924cfd0826..5a400963cc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Tue Dec 25 16:16:54 2012  Koichi Sasada  <ko1@atdot.net>
+
+	* vm_core.h (RUBY_VM_THREAD_VM_STACK_SIZE): change default
+	  VM stack size (128 KB or  256 KB -> 512 KB or 1024 KB).
+	  This re-sizing corrects smaller value introduced at r38478.
+	  Newer value is same VM stack size of Ruby 1.9.
+	  [ruby-dev:46797] [ruby-trunk - Bug #7603]
+
 Tue Dec 25 13:38:12 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* error.c (compile_err_append, compile_warn_print, warn_print): use
diff --git a/vm_core.h b/vm_core.h
index 4a45394121..91b8ea7bf0 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -407,7 +407,7 @@ typedef struct rb_vm_struct {
 
 #define RUBY_VM_SIZE_ALIGN 4096
 
-#define RUBY_VM_THREAD_VM_STACK_SIZE          (  32 * 1024 * sizeof(VALUE)) /*  128 KB or  256 KB */
+#define RUBY_VM_THREAD_VM_STACK_SIZE          ( 128 * 1024 * sizeof(VALUE)) /*  512 KB or 1024 KB */
 #define RUBY_VM_THREAD_VM_STACK_SIZE_MIN      (   2 * 1024 * sizeof(VALUE)) /*    8 KB or   16 KB */
 #define RUBY_VM_THREAD_MACHINE_STACK_SIZE     ( 128 * 1024 * sizeof(VALUE)) /*  512 KB or 1024 KB */
 #define RUBY_VM_THREAD_MACHINE_STACK_SIZE_MIN (  16 * 1024 * sizeof(VALUE)) /*   64 KB or  128 KB */