diff --git a/src/share/vm/runtime/thread.cpp b/src/share/vm/runtime/thread.cpp index 5a09f774b62b4756073e566087aaee44c93739cc..1de74558377105670ef932ec0892019758edf3a6 100644 --- a/src/share/vm/runtime/thread.cpp +++ b/src/share/vm/runtime/thread.cpp @@ -2756,13 +2756,17 @@ void Threads::threads_do(ThreadClosure* tc) { // For now, just manually iterate through them. tc->do_thread(VMThread::vm_thread()); Universe::heap()->gc_threads_do(tc); - { - // Grab the Terminator_lock to prevent watcher_thread from being terminated. - MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); - WatcherThread *wt = WatcherThread::watcher_thread(); - if (wt != NULL) - tc->do_thread(wt); - } + WatcherThread *wt = WatcherThread::watcher_thread(); + // Strictly speaking, the following NULL check isn't sufficient to make sure + // the data for WatcherThread is still valid upon being examined. However, + // considering that WatchThread terminates when the VM is on the way to + // exit at safepoint, the chance of the above is extremely small. The right + // way to prevent termination of WatcherThread would be to acquire + // Terminator_lock, but we can't do that without violating the lock rank + // checking in some cases. + if (wt != NULL) + tc->do_thread(wt); + // If CompilerThreads ever become non-JavaThreads, add them here }