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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: "Adam Tlałka" <atlka@pg.gda.pl>
Cc: 7eggert@gmx.de, linux-kernel@vger.kernel.org, torvalds@osdl.org
Subject: Re: [PATCH 0/2] SIGWINCH problem with terminal apps still alive
Date: Sun, 12 Oct 2008 19:03:12 +0100	[thread overview]
Message-ID: <20081012190312.0bd04ab8@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <20081012195957.50feada3@merlin.oi.pg.gda.pl>

> I've read the code. The race problem with xterm or other pty using

Clearly not.

> program in 2.6.26 appeared because one app called ioctl(TIOCSWINSZ) on
> the master side while other read winsize (TIOCGWINSZ) using client side
> (slave). So in one ioctl() call tty == master and in other tty ==
> real_tty. Of course we can have the opposite situaction so terminal app

Then we end up with both using real_tty.

> Anyway I think that you miss the point. Why using
> real_tty->termios_mutex instead of tty->termios_mutex in tty_do_resize

To avoid deadlocks if you took both as you updated both structures.

> So it seems that tty->termios_mutex could point to different
> location in different calls but real_tty->termios_mutex always points
> to the same location.

You've finally got there - we always work off real_tty. That is why we
can safely use the mutex on the real_tty side.

Alan

  reply	other threads:[~2008-10-12 18:04 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bjXel-4CU-17@gated-at.bofh.it>
     [not found] ` <bjYap-5Q0-25@gated-at.bofh.it>
     [not found]   ` <bk30i-3Gx-1@gated-at.bofh.it>
     [not found]     ` <bk6AV-8ms-7@gated-at.bofh.it>
     [not found]       ` <bkrvO-1HF-49@gated-at.bofh.it>
     [not found]         ` <blePJ-6rI-3@gated-at.bofh.it>
     [not found]           ` <blmDC-7ZU-7@gated-at.bofh.it>
2008-10-11 14:04             ` [PATCH 0/1] " Bodo Eggert
2008-10-11 17:58               ` Alan Cox
2008-10-12 12:32                 ` [PATCH 0/2] " Adam Tlałka
2008-10-12 14:22                   ` Alan Cox
2008-10-12 17:59                     ` Adam Tlałka
2008-10-12 18:03                       ` Alan Cox [this message]
2008-10-12 19:01                         ` Adam Tlałka
2008-10-12 20:22                           ` Alan Cox
2008-10-13  9:59                             ` Bodo Eggert
2008-10-13 10:01                               ` Alan Cox
2008-10-13 12:07                                 ` Bodo Eggert
2008-10-14 12:51                                   ` [PATCH 0/3] " Adam Tlałka
2008-10-14 14:11                                     ` [PATCH 0/4] " Adam Tlałka
2008-10-16 10:27                                       ` [PATCH 0/5] " Adam Tlałka
2008-10-16 10:52                                         ` Alan Cox
2008-10-16 11:43                                           ` Adam Tlałka
2008-10-17  8:39                                             ` Adam Tlałka

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