Index: signal.c
===================================================================
--- signal.c (revision 26907)
+++ signal.c (working copy)
@@ -1065,6 +1065,20 @@ ruby_sig_finalize(void)
     }
 }
 
+void
+rb_signal_redefine_for_thread(void)
+{
+    static const int redefine_list[] = {SIGILL};
+    rb_vm_t *vm = GET_VM();
+    int i;
+
+    for (i = 0; i < sizeof(redefine_list) / sizeof(int); i++) {
+	int sig = redefine_list[i];
+	if (vm->trap_list[sig].cmd) {
+	    ruby_signal(sig, sighandler);
+	}
+    }
+}
 
 #ifdef RUBY_DEBUG_ENV
 int ruby_enable_coredump = 0;
Index: thread_win32.c
===================================================================
--- thread_win32.c (revision 26907)
+++ thread_win32.c (working copy)
@@ -466,6 +466,7 @@ thread_start_func_1(void *th_ptr)
     volatile HANDLE thread_id = th->thread_id;
 
     native_thread_init_stack(th);
+    rb_signal_redefine_for_thread();
     th->native_thread_data.interrupt_event = CreateEvent(0, TRUE, FALSE, 0);
 
     /* run */