netdev - Re: [PATCH net v2 1/1] mlxbf_gige: Fix kernel panic at shutdown

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Message-ID: <20230613090920.GW12152@unreal>
Date: Tue, 13 Jun 2023 12:09:20 +0300
From: Leon Romanovsky <leon@...nel.org>
To: Vladimir Oltean <olteanv@...il.com>
Cc: Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
	Asmaa Mnebhi <asmaa@...dia.com>, davem@...emloft.net,
	edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
	netdev@...r.kernel.org, cai.huoqing@...ux.dev, brgl@...ev.pl,
	chenhao288@...ilicon.com, huangguangbin2@...wei.com,
	David Thompson <davthompson@...dia.com>
Subject: Re: [PATCH net v2 1/1] mlxbf_gige: Fix kernel panic at shutdown

On Tue, Jun 13, 2023 at 11:30:02AM +0300, Vladimir Oltean wrote:
> On Tue, Jun 13, 2023 at 10:19:59AM +0300, Leon Romanovsky wrote:
> > But once child finishes device_shutdown(), it will be removed from devices_kset
> > list and dev->driver should be NULL at that point for the child.
> 
> What piece of code would make dev->driver be NULL for devices that have
> been shut down by device_shutdown()?

You are right here and I'm wrong on that point, dev->driver is set to
NULL in all other places where the device is going to be reused and not
in device_shutdown().

Unfortunately, it doesn't change a lot in our conversation, as device_shutdown()
is very specific call which is called in two flows: kernel_halt() and kernel_restart().

In both flows, it is end game.

Thanks