--- lib/libthr/thread/thr_rtld.c.orig	2011-01-23 09:17:50.657791000 +0900
+++ lib/libthr/thread/thr_rtld.c	2012-04-12 02:48:05.091322596 +0900
@@ -52,6 +52,10 @@ static void	_thr_rtld_wlock_acquire(void
 
 struct rtld_lock {
 	struct	urwlock	lock;
+	struct	pthread * volatile owner;
+	int	nested;
+	int	count_rw; /* total rlock-within-wlock incidents */
+	int	count_ww; /* total wlock-within-wlock incidents */
 	char		_pad[CACHE_LINE_SIZE - sizeof(struct urwlock)];
 };
 
@@ -106,6 +110,15 @@ _thr_rtld_lock_destroy(void *lock)
 		errno = errsave;		\
 }
 
+#define HANDLE_NESTED_ACQ(statfield) {					\
+		if ((l->lock.rw_state & URWLOCK_WRITE_OWNER) != 0 &&	\
+		    l->owner == curthread) {				\
+			l->nested++;					\
+			l->statfield++;					\
+			return;						\
+		}							\
+	}
+
 static void
 _thr_rtld_rlock_acquire(void *lock)
 {
@@ -117,6 +130,7 @@ _thr_rtld_rlock_acquire(void *lock)
 	SAVE_ERRNO();
 	l = (struct rtld_lock *)lock;
 
+	HANDLE_NESTED_ACQ(count_rw);
 	THR_CRITICAL_ENTER(curthread);
 	while (_thr_rwlock_rdlock(&l->lock, 0, NULL) != 0)
 		;
@@ -135,9 +149,11 @@ _thr_rtld_wlock_acquire(void *lock)
 	SAVE_ERRNO();
 	l = (struct rtld_lock *)lock;
 
+	HANDLE_NESTED_ACQ(count_ww);
 	THR_CRITICAL_ENTER(curthread);
 	while (_thr_rwlock_wrlock(&l->lock, NULL) != 0)
 		;
+	l->owner = curthread;
 	RESTORE_ERRNO();
 }
 
@@ -154,6 +170,14 @@ _thr_rtld_lock_release(void *lock)
 	l = (struct rtld_lock *)lock;
 	
 	state = l->lock.rw_state;
+	if ((state & URWLOCK_WRITE_OWNER) != 0) {
+		if (l->nested == 0)
+			l->owner = NULL;
+		else {
+			l->nested--;
+			return;
+		}
+	}
 	if (_thr_rwlock_unlock(&l->lock) == 0) {
 		if ((state & URWLOCK_WRITE_OWNER) == 0)
 			curthread->rdlock_count--;