Date: Thu, 25 Nov 2010 19:28:40 -0500
From: Kyle McMartin <kyle@mcmartin.ca>
To: Jiri Slaby <jslaby@suse.cz>
Cc: gregkh@suse.de, akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
        jirislaby@gmail.com, Kyle McMartin <kyle@mcmartin.ca>,
        Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [PATCH 1/1] TTY: don't allow reopen when ldisc is changing
Message-ID: <20101126002840.GL22651@bombadil.infradead.org>
References: <4CEE93FF.3040507@suse.cz>
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On Thu, Nov 25, 2010 at 06:16:23PM +0100, Jiri Slaby wrote:
> -	if (test_bit(TTY_CLOSING, &tty->flags))
> +	if (test_bit(TTY_CLOSING, &tty->flags) ||
> +			test_bit(TTY_LDISC_CHANGING, &tty->flags))
>  		return -EIO;
>  
>  	if (driver->type == TTY_DRIVER_TYPE_PTY &&

Unfortunately, users report this doesn't seem to fix things for them
(built against 2.6.36 (plus another patch you wrote iirc.))

https://bugzilla.redhat.com/show_bug.cgi?id=630464#c27

I tried reverting the TTY patches between 2.6.36 and 2.6.35 and getting
them to test that, and it seems ok:

https://bugzilla.redhat.com/show_bug.cgi?id=630464#c30

So I guess there must be a race here somewhere... I'll keep looking. :/

I would imagine it's something that's probably existed since the dawn of
time but the BKL has just papered over entirely.

Thanks for trying!
  --Kyle
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