Hang in PreClose method during dup2 system call

During fcntl, dup2 system calls if read/write happens then PreClose method gets hang. This issue is not seen if we Signal/Kill the thread first and then call the preClose method.

Signed-off-by: Shruthi.Shruthi1 <[email protected]>

Author: shruacha1234

src/java.base/unix/classes/sun/nio/ch/SourceChannelImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -107,8 +107,8 @@ protected void implCloseSelectableChannel() throws IOException {
                 assert state == ST_CLOSING;
                 long th = thread;
                 if (th != 0) {
-                    nd.preClose(fd);
                     NativeThread.signal(th);
+                    nd.preClose(fd);
 
                     // wait for read operation to end
                     while (thread != 0) {