linux-kernel - Re: [patch] staging: speakup: safely close tty

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Message-ID: <20170713112445.GA2696@sanghar>
Date:   Thu, 13 Jul 2017 12:24:45 +0100
From:   Okash Khawaja <okash.khawaja@...il.com>
To:     Alan Cox <gnomes@...rguk.ukuu.org.uk>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Samuel Thibault <samuel.thibault@...-lyon.org>,
        linux-kernel@...r.kernel.org, William Hubbs <w.d.hubbs@...il.com>,
        Chris Brannon <chris@...-brannons.com>,
        Kirk Reiser <kirk@...sers.ca>, speakup@...ux-speakup.org,
        devel@...verdev.osuosl.org
Subject: Re: [patch] staging: speakup: safely close tty

On Wed, Jul 12, 2017 at 07:25:22PM +0100, Alan Cox wrote:
> > spk_ttyio_initialise_ldisc is called separately for each module (e.g.
> > speakup_apollo, speakup_ltlk etc) when it is loaded. spk_ttyio_release
> > is also called separately for each module when it is unloaded. The ldisc
> > stays around until the last of the modules is unloaded.
> 
> What guarantees that someone hasn't decided to set the ldisc on unrelated
> hardware to speakup (eg on a pty/tty pair).
> > 
> > > 
> > > I'd also btw strongly recommend putting the ldisc and the speakup tty
> > > driver as different modules.  
> > Sure, that makes sense. I will do that following these patches.
> 
> If the ldisc is just unregistered when the module implementing it is
> unloaded then the ref counts on the ldisc module should do everything
> needed if the above isn't correctly handled, and if it is will still be
> cleaner.

Right, I understand now. Thanks. I will update and resend this patch.