Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755415Ab3FPRe7 (ORCPT ); Sun, 16 Jun 2013 13:34:59 -0400 Received: from smtp1.uu.se ([130.238.7.54]:53092 "EHLO smtp1.uu.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755364Ab3FPRe6 (ORCPT ); Sun, 16 Jun 2013 13:34:58 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <20925.63113.555846.464236@pilspetsen.it.uu.se> Date: Sun, 16 Jun 2013 19:31:53 +0200 From: Mikael Pettersson To: Peter Hurley Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Jiri Slaby , Markus Trippelsdorf , David Howells , Mikael Pettersson , Orion Poplawski Subject: Re: [PATCH] tty: Fix transient pty write() EIO In-Reply-To: <1371153397-3687-1-git-send-email-peter@hurleysoftware.com> References: <51B9F36B.6020802@hurleysoftware.com> <1371153397-3687-1-git-send-email-peter@hurleysoftware.com> X-Mailer: VM 7.17 under Emacs 20.7.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2080 Lines: 63 Peter Hurley writes: > Commit 699390354da6c258b65bf8fa79cfd5feaede50b6 > ('pty: Ignore slave pty close() if never successfully opened') > introduced a bug with ptys whereby a write() in parallel with an > open() on an existing pty could mistakenly indicate an I/O error. > > Only indicate an I/O error if the condition on open() actually exists. > > Reported-by: Markus Trippelsdorf > Signed-off-by: Peter Hurley I've tested this for two days on 3.9.0 (where the bug reproduces easily for me, for some reason I can't seem to trigger it with 3.10-rc5), and with the patch I no longer see the bug. Tested-by: Mikael Pettersson > --- > drivers/tty/pty.c | 13 +++++-------- > 1 file changed, 5 insertions(+), 8 deletions(-) > > diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c > index 9c2f1bc..dd08d3d 100644 > --- a/drivers/tty/pty.c > +++ b/drivers/tty/pty.c > @@ -238,14 +238,9 @@ static void pty_flush_buffer(struct tty_struct *tty) > > static int pty_open(struct tty_struct *tty, struct file *filp) > { > - int retval = -ENODEV; > - > if (!tty || !tty->link) > - goto out; > - > - set_bit(TTY_IO_ERROR, &tty->flags); > + return -ENODEV; > > - retval = -EIO; > if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) > goto out; > if (test_bit(TTY_PTY_LOCK, &tty->link->flags)) > @@ -256,9 +251,11 @@ static int pty_open(struct tty_struct *tty, struct file *filp) > clear_bit(TTY_IO_ERROR, &tty->flags); > clear_bit(TTY_OTHER_CLOSED, &tty->link->flags); > set_bit(TTY_THROTTLED, &tty->flags); > - retval = 0; > + return 0; > + > out: > - return retval; > + set_bit(TTY_IO_ERROR, &tty->flags); > + return -EIO; > } > > static void pty_set_termios(struct tty_struct *tty, > -- > 1.8.1.2 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/