linux-kernel - Re: [PATCH 4/5] drivers/tty: make serial/mpsc.c driver explicitly non-modular

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Date:	Sat, 10 Oct 2015 15:18:03 -0400
From:	Paul Gortmaker <paul.gortmaker@...driver.com>
To:	Thierry Reding <thierry.reding@...il.com>
CC:	<linux-kernel@...r.kernel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.com>, <linux-serial@...r.kernel.org>
Subject: Re: [PATCH 4/5] drivers/tty: make serial/mpsc.c driver explicitly
 non-modular

[Re: [PATCH 4/5] drivers/tty: make serial/mpsc.c driver explicitly non-modular] On 09/10/2015 (Fri 15:38) Thierry Reding wrote:

> On Wed, Aug 19, 2015 at 05:48:08PM -0400, Paul Gortmaker wrote:

[...]

> >  static struct platform_driver mpsc_driver = {
> >  	.probe	= mpsc_drv_probe,
> > -	.remove	= mpsc_drv_remove,
> >  	.driver	= {
> >  		.name	= MPSC_CTLR_NAME,
> >  	},
> 
> I don't think this is right. The driver can always be unbound from the
> device via sysfs, in which case it will now leak resources and leave
> behind a dangling UART port.

I suppose it does open the window for root to do something else stupid
he shouldn't be doing anyway...

I think the right thing to do here is for me to send a follow on patch
that does also set:

	.suppress_bind_attrs = true

in the above block, since this is a console device used on 2005 vintage
74xx based powerpc embedded targets, and is essentially always used in
conjunction with SERIAL_MPSC_CONSOLE=y -- there is no sane reason anyone
would ever want to unbind the builtin driver and lose the console.

I'll send a follow on patch doing the above if folks are in agreement
with the above logic.

Thanks,
Paul.
--

> 
> Thierry

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