- Currently, tty::pcon_start flag is cleared before transfer_input()
  in master::write(), however, the code in setup_pseudoconsole()
  waits for transfer_input() using tty::pcon_start. This possibly
  causes the race issue. The patch fixes this potential issue.
---
 winsup/cygwin/fhandler_tty.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc
index cba25ee84..3ed84709e 100644
--- a/winsup/cygwin/fhandler_tty.cc
+++ b/winsup/cygwin/fhandler_tty.cc
@@ -3215,7 +3215,8 @@ fhandler_pty_slave::setup_pseudoconsole ()
          get_ttyp ()->pcon_start_pid = myself->pid;
          WriteFile (get_output_handle (), "\033[6n", 4, &n, NULL);
          ReleaseMutex (input_mutex);
-         while (get_ttyp ()->pcon_start)
+         while (get_ttyp ()->pcon_start_pid)
+           /* wait for completion of transfer_input() in master::write(). */
            Sleep (1);
        }
       /* Attach to the pseudo console which already exits. */
-- 
2.35.1

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