linux-kernel - Re: [PATCH] mcb: Fix incorrect sanity check

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Message-ID: <aSBGvr04PSaZYtaw@MNI-190>
Date: Fri, 21 Nov 2025 12:02:22 +0100
From: Jose Javier Rodriguez Barbarin <dev-josejavier.rodriguez@...gon.com>
To: Johannes Thumshirn <morbidrsa@...il.com>
CC: gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mcb: Fix incorrect sanity check

On Fri, Nov 21, 2025 at 11:54:08AM +0100, Johannes Thumshirn wrote:
> On 11/21/25 11:33 AM, Jose Javier Rodriguez Barbarin wrote:
> > On Thu, Nov 20, 2025 at 12:48:45PM +0100, Johannes Thumshirn wrote:
> > > On 11/20/25 12:37 PM, Jose Javier Rodriguez Barbarin wrote:
> > > > __mcb_register_driver() makes some sanity checks over mcb_driver
> > > > to check if .probe and .remove callbacks are set. However, not all
> > > > mcb device drivers implement .remove callback.
> > > > 
> > > > Remove .remove check to ensure all mcb device drivers can be loaded.
> > > The only driver I can see that doesn't implement a .remove method is
> > > gpio-menz127.c.
> > Yes. In the past gpio-menz127.c also implemented .remove method, however in
> > 
> > 3bd13ae04ccc ("gpio: menz127: simplify error path and remove remove()")
> > 
> > The driver changed, using now devm_* functions so .remove was no longer necessary.
> > 
> > > Is this safe?
> > > 
> >  From the point of view of mcb bus it should be safe becase I protected the call
> > of .remove on mcb_remove(), preventing possible crashes when the driver is removed
> > from the bus.
> > 
> > I'm afraid I'm lossing something because I cannot understand why these changes are or
> > not safe. Could you explain me why you understand that these changes are unsafe?
> 
> 
> Thanks this is the information I was missing from the changelog. I'll change
> the commit message to:
> 
> __mcb_register_driver() makes some sanity checks over mcb_driver
> to check if .probe and .remove callbacks are set. However, since commit
> 3bd13ae04ccc ("gpio: menz127: simplify error path and remove remove()")
> removed the .remove callback from menz127-gpio.c, not all mcb device
> drivers implement .remove callback.
> 
> Remove .remove check to ensure all mcb device drivers can be loaded.
> 
> I'll also add
> 
> Fixes: 3bd13ae04ccc ("gpio: menz127: simplify error path and remove remove()")
> 
> 
> Thanks,
> 
>     Johannes
> 

Hi Johannes,

It is OK to me.

Thank you so much.

	Javier R.