* fhandler_tty.cc (fhandler_pty_slave::write): Fix potential exit from loop

with write mutex held.  Delete redundant mutex release.  Clear tty error once
we've grabbed it.

winsup/cygwin/ChangeLog

@@ -1,3 +1,9 @@
+2012-10-15  Christopher Faylor  <me.cygwin2012@cgf.cx>
+
+	* fhandler_tty.cc (fhandler_pty_slave::write): Fix potential exit from
+	loop with write mutex held.  Delete redundant mutex release.  Clear tty
+	error once we've grabbed it.
+
 2012-10-15  Corinna Vinschen  <corinna@vinschen.de>
 
 	* fhandler_raw.cc (fhandler_dev_raw::fhandler_dev_raw): Drop gratuitous

winsup/cygwin/fhandler_tty.cc

@@ -663,6 +663,8 @@ fhandler_pty_slave::write (const void *ptr, size_t len)
 	{
 	  set_errno (get_ttyp ()->write_error);
 	  towrite = (DWORD) -1;
+	  get_ttyp ()->write_error = 0;
+	  release_output_mutex ();
 	  break;
 	}
 
@@ -681,7 +683,6 @@ fhandler_pty_slave::write (const void *ptr, size_t len)
 	    }
 	  raise (SIGHUP);		/* FIXME: Should this be SIGTTOU? */
 	  towrite = (DWORD) -1;
-	  release_output_mutex ();
 	  break;
 	}
     }

winsup/cygwin/release/1.7.17

@@ -1,6 +1,9 @@
 Bug fixes:
 ----------
 
+- Prevent CTRL-S hang.
+  Fixes: http://cygwin.com/ml/cygwin/2012-10/threads.html#00089
+
 - Revamp signals so that signals-to-threads more closely mimic Linux
   operation.
   First step of fix for: http://cygwin.com/ml/cygwin/2012-05/msg00186.html