netdev - Re: [PATCH] driver: usb: nullify dangling pointer in cdc_ncm

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Date:   Tue, 19 Apr 2022 22:25:54 +0200
From:   Bjørn Mork <bjorn@...k.no>
To:     Oliver Neukum <oneukum@...e.com>
Cc:     Andy Shevchenko <andy.shevchenko@...il.com>,
        Johan Hovold <johan@...nel.org>,
        Oleksij Rempel <linux@...pel-privat.de>,
        Dongliang Mu <dzm91@...t.edu.cn>,
        Oliver Neukum <oliver@...kum.org>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Dongliang Mu <mudongliangabcd@...il.com>,
        syzbot+eabbf2aaa999cc507108@...kaller.appspotmail.com,
        USB <linux-usb@...r.kernel.org>, netdev <netdev@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] driver: usb: nullify dangling pointer in cdc_ncm_free

Oliver Neukum <oneukum@...e.com> writes:

> It seems to me that fundamentally the order of actions to handle
> a hotunplug must mirror the order in a hotplug. We can add more hooks
> if that turns out to be necessary for some drivers, but the basic
> reverse mirrored order must be supported and I very much favor
> restoring it as default.

FWIW, I agree 100% with this.  Please go ahead with the revert of commit
2c9d6c2b871d ("usbnet: run unbind() before unregister_netdev()").

AFAICS, your proposed new hook should solve the original problem just
fine.


Bjørn