diff --git a/eval.c b/eval.c
index d5f2c4c..e563b27 100644
--- a/eval.c
+++ b/eval.c
@@ -441,8 +441,6 @@ setup_exception(rb_thread_t *th, int tag, volatile VALUE mesg)
 	JUMP_TAG(TAG_FATAL);
     }
 
-    rb_trap_restore_mask();
-
     if (tag != TAG_FATAL) {
 	EXEC_EVENT_HOOK(th, RUBY_EVENT_RAISE, th->cfp->self, 0, 0);
     }
diff --git a/eval_intern.h b/eval_intern.h
index e1316bf..cc8b489 100644
--- a/eval_intern.h
+++ b/eval_intern.h
@@ -212,7 +212,6 @@ void rb_vm_set_progname(VALUE filename);
 void rb_thread_terminate_all(void);
 VALUE rb_vm_top_self();
 VALUE rb_vm_cbase(void);
-void rb_trap_restore_mask(void);
 
 #ifndef CharNext		/* defined as CharNext[AW] on Windows. */
 #define CharNext(p) ((p) + mblen((p), RUBY_MBCHAR_MAXSIZE))
diff --git a/lib/test/unit/parallel.rb b/lib/test/unit/parallel.rb
index e433779..bdf08fb 100644
--- a/lib/test/unit/parallel.rb
+++ b/lib/test/unit/parallel.rb
@@ -74,7 +74,6 @@ module Test
         @@stop_auto_run = true
         @opts = @options.dup
 
-        Signal.trap(:INT,"IGNORE")
         @old_loadpath = []
         begin
           @stdout = increment_io(STDOUT)
diff --git a/process.c b/process.c
index 0f60cfb..4965ae6 100644
--- a/process.c
+++ b/process.c
@@ -989,9 +989,9 @@ static int forked_child = 0;
  * Therefore we have to kill internal threads at once. [ruby-core: 10583]
  */
 #define before_exec() \
-    (rb_enable_interrupt(), (void)(forked_child ? 0 : (rb_thread_stop_timer_thread(), 1)))
+    ((void)(forked_child ? 0 : (rb_thread_stop_timer_thread(), 1)))
 #define after_exec() \
-  (rb_thread_reset_timer_thread(), rb_thread_start_timer_thread(), forked_child = 0, rb_disable_interrupt())
+    (rb_thread_reset_timer_thread(), rb_thread_start_timer_thread(), forked_child = 0)
 #define before_fork() before_exec()
 #define after_fork() (GET_THREAD()->thrown_errinfo = 0, after_exec())
 
@@ -2915,43 +2915,12 @@ rb_f_abort(int argc, VALUE *argv)
 void
 rb_syswait(rb_pid_t pid)
 {
-    static int overriding;
-#ifdef SIGHUP
-    RETSIGTYPE (*hfunc)(int) = 0;
-#endif
-#ifdef SIGQUIT
-    RETSIGTYPE (*qfunc)(int) = 0;
-#endif
-    RETSIGTYPE (*ifunc)(int) = 0;
     int status;
-    int i, hooked = FALSE;
-
-    if (!overriding) {
-#ifdef SIGHUP
-	hfunc = signal(SIGHUP, SIG_IGN);
-#endif
-#ifdef SIGQUIT
-	qfunc = signal(SIGQUIT, SIG_IGN);
-#endif
-	ifunc = signal(SIGINT, SIG_IGN);
-	overriding = TRUE;
-	hooked = TRUE;
-    }
+    int i;
 
     do {
 	i = rb_waitpid(pid, &status, 0);
     } while (i == -1 && errno == EINTR);
-
-    if (hooked) {
-#ifdef SIGHUP
-	signal(SIGHUP, hfunc);
-#endif
-#ifdef SIGQUIT
-	signal(SIGQUIT, qfunc);
-#endif
-	signal(SIGINT, ifunc);
-	overriding = FALSE;
-    }
 }
 
 static VALUE
diff --git a/signal.c b/signal.c
index c7ad67f..02c963c 100644
--- a/signal.c
+++ b/signal.c
@@ -312,6 +312,12 @@ interrupt_init(int argc, VALUE *argv, VALUE self)
 void
 ruby_default_signal(int sig)
 {
+    sigset_t sigmask;
+
+    sigemptyset(&sigmask);
+    sigaddset(&sigmask, sig);
+    pthread_sigmask(SIG_UNBLOCK, &sigmask, NULL);
+
     signal(sig, SIG_DFL);
     raise(sig);
 }
@@ -535,14 +541,6 @@ rb_signal_buff_size(void)
     return signal_buff.size;
 }
 
-#if USE_TRAP_MASK
-# ifdef HAVE_SIGPROCMASK
-static sigset_t trap_last_mask;
-# else
-static int trap_last_mask;
-# endif
-#endif
-
 #if HAVE_PTHREAD_H
 #include <pthread.h>
 #endif
@@ -623,14 +621,6 @@ sigsegv(int sig SIGINFO_ARG)
 }
 #endif
 
-#ifdef SIGPIPE
-static RETSIGTYPE
-sigpipe(int sig)
-{
-    /* do nothing */
-}
-#endif
-
 static void
 signal_exec(VALUE cmd, int safe, int sig)
 {
@@ -746,7 +736,7 @@ default_handler(int sig)
 #endif
 #ifdef SIGPIPE
       case SIGPIPE:
-        func = sigpipe;
+	func = SIG_IGN;
         break;
 #endif
       default:
@@ -893,19 +883,10 @@ trap_ensure(struct trap_arg *arg)
 {
     /* enable interrupt */
     pthread_sigmask(SIG_SETMASK, &arg->mask, NULL);
-    trap_last_mask = arg->mask;
     return 0;
 }
 #endif
 
-void
-rb_trap_restore_mask(void)
-{
-#if USE_TRAP_MASK
-    pthread_sigmask(SIG_SETMASK, &trap_last_mask, NULL);
-#endif
-}
-
 /*
  * call-seq:
  *   Signal.trap( signal, command ) -> obj
@@ -1038,7 +1019,6 @@ init_sigchld(int sig)
 #if USE_TRAP_MASK
     sigdelset(&mask, sig);
     pthread_sigmask(SIG_SETMASK, &mask, NULL);
-    trap_last_mask = mask;
 #endif
 }
 #endif
@@ -1143,7 +1123,7 @@ Init_signal(void)
 #endif
     }
 #ifdef SIGPIPE
-    install_sighandler(SIGPIPE, sigpipe);
+    install_sighandler(SIGPIPE, SIG_IGN);
 #endif
 
 #if defined(SIGCLD)
@@ -1151,4 +1131,6 @@ Init_signal(void)
 #elif defined(SIGCHLD)
     init_sigchld(SIGCHLD);
 #endif
+
+    rb_disable_interrupt();
 }
diff --git a/thread_pthread.c b/thread_pthread.c
index d14f2b2..4416f24 100644
--- a/thread_pthread.c
+++ b/thread_pthread.c
@@ -996,6 +996,9 @@ thread_timer(void *dummy)
 {
     struct timespec timeout_10ms;
 
+    /* only timer thread recieve signal */
+    rb_enable_interrupt();
+
     timeout_10ms.tv_sec = 0;
     timeout_10ms.tv_nsec = 10 * 1000 * 1000;
 
@@ -1024,8 +1027,6 @@ thread_timer(void *dummy)
 static void
 rb_thread_create_timer_thread(void)
 {
-    rb_enable_interrupt();
-
     if (!timer_thread_id) {
 	pthread_attr_t attr;
 	int err;
@@ -1046,7 +1047,6 @@ rb_thread_create_timer_thread(void)
 	native_cond_wait(&timer_thread_cond, &timer_thread_lock);
 	native_mutex_unlock(&timer_thread_lock);
     }
-    rb_disable_interrupt(); /* only timer thread recieve signal */
 }
 
 static int
diff --git a/vm_eval.c b/vm_eval.c
index 54debd7..35e5ebf 100644
--- a/vm_eval.c
+++ b/vm_eval.c
@@ -1442,7 +1442,6 @@ rb_throw_obj(VALUE tag, VALUE value)
 	RB_GC_GUARD(desc);
 	rb_raise(rb_eArgError, "uncaught throw %s", RSTRING_PTR(desc));
     }
-    rb_trap_restore_mask();
     th->errinfo = NEW_THROW_OBJECT(tag, 0, TAG_THROW);
 
     JUMP_TAG(TAG_THROW);