linux-kernel - Re: [Fwd: [PATCH v2 0/4] TTY: port hangup and close fixes]

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1362520976.18799.134.camel@thor.lan>
Date:	Tue, 05 Mar 2013 17:02:56 -0500
From:	Peter Hurley <peter@...leysoftware.com>
To:	Jiri Slaby <jslaby@...e.cz>
Cc:	jhovold@...il.com, Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Alan Stern <stern@...land.harvard.edu>,
	USB list <linux-usb@...r.kernel.org>,
	linux-serial@...r.kernel.org, Alan Cox <alan@...rguk.ukuu.org.uk>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [Fwd: [PATCH v2 0/4] TTY: port hangup and close fixes]

On Tue, 2013-03-05 at 22:56 +0100, Jiri Slaby wrote:
> On 03/05/2013 06:06 PM, Peter Hurley wrote:
> >>> @@ -225,15 +232,13 @@ void tty_port_hangup(struct tty_port *port)
> >>         spin_lock_irqsave(&port->lock, flags);
> >>         port->count = 0;
> >>         port->flags &= ~ASYNC_NORMAL_ACTIVE;
> >> -       if (port->tty) {
> >> +       if (port->tty)
> >>                 set_bit(TTY_IO_ERROR, &port->tty->flags);
> >> -               tty_kref_put(port->tty);
> >> -       }
> >> -       port->tty = NULL;
> >>         spin_unlock_irqrestore(&port->lock, flags);
> >>> +       tty_port_shutdown(port, port->tty);
> >>
> >> What prevents port->tty to be NULL here already?
> > 
> > Nothing. That's why it's tested in tty_port_shutdown() above.
> 
> I know :).

Sorry :)

> But the question is rather don't we want to pass the real
> refcounted port->tty (take a snapshot inside the lock) instead?

I think that's why he moved the kref release to after the shutdown (via
tty_port_set_tty()) -- but I'm tired and maybe I'm missing something
here?

Regards,
Peter Hurley


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/