1 files changed, 25 insertions, 2 deletions
diff --git a/pthread/pt-cancel.c b/pthread/pt-cancel.c
index d19c557..96c77f7 100644
--- a/pthread/pt-cancel.c
+++ b/pthread/pt-cancel.c
@@ -31,10 +31,33 @@ pthread_cancel (pthread_t t)
   if (! p)
     return ESRCH;
 
+  __pthread_mutex_lock (&p->cancel_lock);
+  if (p->cancel_pending)
+    {
+      __pthread_mutex_unlock (&p->cancel_lock);
+      return 0;
+    }
+
   p->cancel_pending = 1;
-  if (p->cancel_state == PTHREAD_CANCEL_ENABLE
-      && p->cancel_type == PTHREAD_CANCEL_ASYNCHRONOUS)
+
+  if (p->cancel_state != PTHREAD_CANCEL_ENABLE)
+    {
+      __pthread_mutex_unlock (&p->cancel_lock);
+      return 0;
+    }
+
+  if (p->cancel_type == PTHREAD_CANCEL_ASYNCHRONOUS)
+    /* CANCEL_LOCK is unlocked by this call.  */
     err = __pthread_do_cancel (p);
+  else
+    {
+      if (p->cancel_hook != NULL)
+	/* Thread blocking on a cancellation point.  Invoke hook to unblock.
+	   See __pthread_cond_timedwait_internal.  */
+	p->cancel_hook (p->cancel_hook_arg);
+
+      __pthread_mutex_unlock (&p->cancel_lock);
+    }
 
   return err;
 }