From 5c6790519b12afae688c87ae3f55ee5eec1a6dcc Mon Sep 17 00:00:00 2001
From: Eric Holk <eholk@mozilla.com>
Date: Mon, 15 Aug 2011 11:34:12 -0700
Subject: Reducing the chances for race conditions in join.

---
 src/rt/rust_kernel.cpp | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

(limited to 'src/rt/rust_kernel.cpp')

diff --git a/src/rt/rust_kernel.cpp b/src/rt/rust_kernel.cpp
index c11a5b69b73..ceddcf5b1c9 100644
--- a/src/rt/rust_kernel.cpp
+++ b/src/rt/rust_kernel.cpp
@@ -160,7 +160,17 @@ rust_kernel::get_task_by_id(rust_task_id id) {
     rust_task *task = NULL;
     // get leaves task unchanged if not found.
     task_table.get(id, &task);
-    if(task) task->ref();
+    if(task) {
+        if(task->get_ref_count() == 0) {
+            // this means the destructor is running, since the destructor
+            // grabs the kernel lock to unregister the task. Pretend this
+            // doesn't actually exist.
+            return NULL;
+        }
+        else {
+            task->ref();
+        }
+    }
     return task;
 }
 
-- 
cgit 1.4.1-3-g733a5