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Date:   Mon, 1 Mar 2021 10:18:41 +0100
From:   Johan Hovold <johan@kernel.org>
To:     Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Manivannan Sadhasivam <mani@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH] USB: serial: xr: fix NULL-deref on disconnect
Message-ID: <YDyxcQfUabhJruuA@hovoldconsulting.com>
References: <20210226100826.18987-1-johan@kernel.org>
 <20210226115447.6ace5490@coco.lan>
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On Fri, Feb 26, 2021 at 11:54:47AM +0100, Mauro Carvalho Chehab wrote:
> Em Fri, 26 Feb 2021 11:08:26 +0100
> Johan Hovold <johan@kernel.org> escreveu:
> 
> > Claiming the sibling control interface is a bit more involved and
> > specifically requires adding support to USB-serial core for managing
> > either interface being unbound first, something which could otherwise
> > lead to a NULL-pointer dereference.
> > 
> > Similarly, additional infrastructure is also needed to handle suspend
> > properly.
> > 
> > Since the driver currently isn't actually using the control interface,
> > we can defer this for now by simply not claiming the control interface.
> > 
> > Fixes: c2d405aa86b4 ("USB: serial: add MaxLinear/Exar USB to Serial driver")
> > Reported-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> > Cc: Manivannan Sadhasivam <mani@kernel.org>
> > Signed-off-by: Johan Hovold <johan@kernel.org>
> 
> That solved the issue with XR21V1410:
> 
> 	[ 8176.265862] usbcore: registered new interface driver xr_serial
> 	[ 8176.265885] usbserial: USB Serial support registered for xr_serial
> 	[ 8176.265921] xr_serial 2-1:1.1: xr_serial converter detected
> 	[ 8176.266041] usb 2-1: xr_serial converter now attached to ttyUSB0
> 	[ 8176.268023] printk: console [ttyUSB0] enabled
> 	[ 8186.512841] usb 2-1: USB disconnect, device number 5
> 	[ 8186.513131] printk: console [ttyUSB0] disabled
> 	[ 8186.513340] xr_serial ttyUSB0: xr_serial converter now disconnected from ttyUSB0
> 	[ 8186.513376] xr_serial 2-1:1.1: device disconnected
> 
> Tested-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Thanks for testing, and thanks to Greg and Manivannan for the review.

Now applied.

Johan