public inbox for
 help / color / mirror / Atom feed
From: Takashi Yano <>
Subject: [PATCH 3/8] Cygwin: pty: Prevent deadlock on echo output.
Date: Sun, 13 Feb 2022 23:39:05 +0900	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

- 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/ | 2 --
 1 file changed, 2 deletions(-)

diff --git a/winsup/cygwin/ b/winsup/cygwin/
index 7bef6958c..7e065c46a 100644
--- a/winsup/cygwin/
+++ b/winsup/cygwin/
@@ -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 ();

  parent reply	other threads:[~2022-02-13 14:40 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-13 14:39 [PATCH 0/8] Several modifications for pty and console code Takashi Yano
2022-02-13 14:39 ` [PATCH 1/8] Cygwin: pty, console: Fix Ctrl-C handling for non-cygwin apps Takashi Yano
2022-02-13 14:39 ` [PATCH 2/8] Cygwin: pty: Pass Ctrl-Z (EOF) to non-cygwin apps with disable_pcon Takashi Yano
2022-02-13 14:39 ` Takashi Yano [this message]
2022-02-13 14:39 ` [PATCH 4/8] Cygwin: pty: Revise the code to wait for completion of forwarding Takashi Yano
2022-02-13 14:39 ` [PATCH 5/8] Cygwin: pty: Discard input in from_master_nat pipe on signal as well Takashi Yano
2022-02-13 14:39 ` [PATCH 6/8] Cygwin: pty: Fix a bug in tty_min::segpgid() Takashi Yano
2022-02-13 14:39 ` [PATCH 7/8] Cygwin: console: Fix console mode for non-cygwin inferior of GDB Takashi Yano
2022-02-13 14:39 ` [PATCH 8/8] Cygwin: console: Set console mode even if stdin/stdout is redirected Takashi Yano

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).