From bddd9c1c417e97791c44241cf94753e90464501c Mon Sep 17 00:00:00 2001 From: Takashi Yano Date: Thu, 10 Feb 2022 17:22:11 +0900 Subject: Cygwin: pty: Prevent deadlock on echo output. - If the slave process writes a lot of text output, doecho() can cause deadlock. This is because output_mutex is held in slave:: write() and if WriteFile() is blocked due to pipe full, doecho() tries to acquire output_mutex and gets into deadlock. With this patch, the deadlock is prevented on the sacrifice of atomicity of doecho(). --- winsup/cygwin/fhandler_tty.cc | 2 -- 1 file changed, 2 deletions(-) diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc index 7bef695..7e065c4 100644 --- a/winsup/cygwin/fhandler_tty.cc +++ b/winsup/cygwin/fhandler_tty.cc @@ -496,11 +496,9 @@ void fhandler_pty_master::doecho (const void *str, DWORD len) { ssize_t towrite = len; - acquire_output_mutex (mutex_timeout); if (!process_opost_output (echo_w, str, towrite, true, get_ttyp (), is_nonblocking ())) termios_printf ("Write to echo pipe failed, %E"); - release_output_mutex (); } int -- cgit v1.1