--- eval.c.orig	2009-12-21 08:11:42.000000000 +0000
+++ eval.c
@@ -10879,7 +10879,7 @@ rb_thread_remove(th)
 #if defined(_THREAD_SAFE) || defined(HAVE_SETITIMER)
     /* if this is the last ruby thread, stop timer signals */
     if (th->next == th->prev && th->next == main_thread) {
-	rb_thread_stop_timer();
+	rb_thread_stop_timer(0);
     }
 #endif
 }
@@ -12329,6 +12329,18 @@ thread_timer(dummy)
     return NULL;
 }
 
+/* fix inconsistent data */
+static void
+rb_thread_stop_timer_atfork(void)
+{
+    if (!thread_init) return;
+#if !defined(__NetBSD__)
+    (void)pthread_cond_init(&time_thread.cond, NULL);
+    (void)pthread_mutex_init(&time_thread.lock, NULL);
+#endif
+    thread_init = 0;
+}
+
 void
 rb_thread_start_timer()
 {
@@ -12343,21 +12355,27 @@ rb_thread_start_timer()
     safe_mutex_lock(&time_thread.lock);
     if (pthread_create(&time_thread.thread, 0, thread_timer, args) == 0) {
 	thread_init = 1;
-	pthread_atfork(0, 0, rb_thread_stop_timer);
+	pthread_atfork(0, 0, rb_thread_stop_timer_atfork);
 	pthread_cond_wait(&start, &time_thread.lock);
     }
     pthread_cleanup_pop(1);
 }
 
 void
-rb_thread_stop_timer()
+rb_thread_stop_timer(int doexec)
 {
     if (!thread_init) return;
+#if defined(__NetBSD__)
+    if (doexec) {
+#endif
     safe_mutex_lock(&time_thread.lock);
     pthread_cond_signal(&time_thread.cond);
     thread_init = 0;
     pthread_cleanup_pop(1);
     pthread_join(time_thread.thread, NULL);
+#if defined(__NetBSD__)
+    }
+#endif
 }
 #elif defined(HAVE_SETITIMER)
 static void
@@ -12389,7 +12407,7 @@ rb_thread_start_timer()
 }
 
 void
-rb_thread_stop_timer()
+rb_thread_stop_timer(int dummy)
 {
     struct itimerval tval;
 
@@ -12406,7 +12424,7 @@ int rb_thread_tick = THREAD_TICK;
 
 #if defined(HAVE_SETITIMER) || defined(_THREAD_SAFE)
 #define START_TIMER() (thread_init ? (void)0 : rb_thread_start_timer())
-#define STOP_TIMER() (rb_thread_stop_timer())
+#define STOP_TIMER() (rb_thread_stop_timer(0))
 #else
 #define START_TIMER() ((void)0)
 #define STOP_TIMER() ((void)0)


--- process.c.orig	2008-06-29 09:34:43.000000000 +0000
+++ process.c
@@ -115,6 +115,7 @@ static VALUE S_Tms;
 #define preserving_errno(stmts) \
 	do {int saved_errno = errno; stmts; errno = saved_errno;} while (0)
 
+static int doing_rb_f_exec = 0;
 
 /*
  *  call-seq:
@@ -920,7 +921,7 @@ char *strtok();
 #endif
 
 #ifdef HAVE_SETITIMER
-#define before_exec() rb_thread_stop_timer()
+#define before_exec() rb_thread_stop_timer(doing_rb_f_exec)
 #define after_exec() rb_thread_start_timer()
 #else
 #define before_exec()
@@ -1289,7 +1290,13 @@ rb_f_exec(argc, argv)
 	SafeStringValue(prog);
     }
     proc_prepare_args(&earg, argc, argv, prog);
+#if defined(__NetBSD__)
+    doing_rb_f_exec = 1;
+#endif
     proc_exec_args((VALUE)&earg);
+#if defined(__NetBSD__)
+    doing_rb_f_exec = 0;
+#endif
     rb_sys_fail(RSTRING(argv[0])->ptr);
     return Qnil;		/* dummy */
 }


--- intern.h.orig	2009-01-22 06:22:00.000000000 +0000
+++ intern.h
@@ -208,7 +208,7 @@ int ruby_cleanup _((int));
 int ruby_exec _((void));
 void rb_gc_mark_threads _((void));
 void rb_thread_start_timer _((void));
-void rb_thread_stop_timer _((void));
+void rb_thread_stop_timer _((int));
 void rb_thread_schedule _((void));
 void rb_thread_wait_fd _((int));
 int rb_thread_fd_writable _((int));