diff --git a/ChangeLog b/ChangeLog
index 15d4f2c39c..e8d3a0919e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Fri Jan 18 15:57:05 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* thread.c (thread_cleanup_func): ignore errors from destroying mutex
+	  of dead thread.  [ruby-core:15069]
+
+	* thread_pthread.c, thread_win32.c (native_thread_destroy): ditto.
+
 Fri Jan 18 15:56:04 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* encoding.c (rb_enc_name_list_i, rb_enc_aliases_enc_i): freeze
diff --git a/thread.c b/thread.c
index 7326c59347..e45062c206 100644
--- a/thread.c
+++ b/thread.c
@@ -281,7 +281,6 @@ thread_cleanup_func(void *th_ptr)
 #ifdef __ia64
     th->machine_register_stack_start = th->machine_register_stack_end = 0;
 #endif
-    native_mutex_destroy(&th->interrupt_lock);
     native_thread_destroy(th);
 }
 
diff --git a/thread_pthread.c b/thread_pthread.c
index 202dc54feb..62bddb722f 100644
--- a/thread_pthread.c
+++ b/thread_pthread.c
@@ -13,7 +13,6 @@
 
 static void native_mutex_lock(pthread_mutex_t *lock);
 static void native_mutex_unlock(pthread_mutex_t *lock);
-static void native_mutex_destroy(pthread_mutex_t *lock);
 static int native_mutex_trylock(pthread_mutex_t *lock);
 static void native_mutex_initialize(pthread_mutex_t *lock);
 static void native_mutex_destroy(pthread_mutex_t *lock);
@@ -156,6 +155,7 @@ Init_native_thread(void)
 static void
 native_thread_destroy(rb_thread_t *th)
 {
+    pthread_mutex_destroy(&th->interrupt_lock);
     pthread_cond_destroy(&th->native_thread_data.sleep_cond);
 }
 
diff --git a/thread_win32.c b/thread_win32.c
index 7c4f402d14..7680a226e3 100644
--- a/thread_win32.c
+++ b/thread_win32.c
@@ -418,6 +418,7 @@ static void
 native_thread_destroy(rb_thread_t *th)
 {
     HANDLE intr = th->native_thread_data.interrupt_event;
+    native_mutex_destroy(&th->interrupt_lock);
     thread_debug("close handle - intr: %p, thid: %p\n", intr, th->thread_id);
     th->native_thread_data.interrupt_event = 0;
     w32_close_handle(intr);