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Date:   Sun, 22 Aug 2021 23:40:54 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     Alvin =?utf-8?Q?=C5=A0ipraga?= <alvin@pqrs.dk>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>, mir@bang-olufsen.dk,
        Alvin =?utf-8?Q?=C5=A0ipraga?= <alsi@bang-olufsen.dk>,
        netdev@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH net-next 1/5] net: dsa: realtek-smi: fix mdio_free
 bug on module unload
Message-ID: <YSLEZmuWlD5kUOlx@lunn.ch>
References: <20210822193145.1312668-1-alvin@pqrs.dk>
 <20210822193145.1312668-2-alvin@pqrs.dk>
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On Sun, Aug 22, 2021 at 09:31:39PM +0200, Alvin Šipraga wrote:
> From: Alvin Šipraga <alsi@bang-olufsen.dk>
> 
> realtek-smi-core fails to unregister the slave MII bus on module unload,
> raising the following BUG warning:
> 
>     mdio_bus.c:650: BUG_ON(bus->state != MDIOBUS_UNREGISTERED);
> 
>     kernel BUG at drivers/net/phy/mdio_bus.c:650!
>     Internal error: Oops - BUG: 0 [#1] PREEMPT_RT SMP
>     Call trace:
>      mdiobus_free+0x4c/0x50
>      devm_mdiobus_free+0x18/0x20
>      release_nodes.isra.0+0x1c0/0x2b0
>      devres_release_all+0x38/0x58
>      device_release_driver_internal+0x124/0x1e8
>      driver_detach+0x54/0xe0
>      bus_remove_driver+0x60/0xd8
>      driver_unregister+0x34/0x60
>      platform_driver_unregister+0x18/0x20
>      realtek_smi_driver_exit+0x14/0x1c [realtek_smi]
> 
> Fix this by duly unregistering the slave MII bus with
> mdiobus_unregister. We do this in the DSA teardown path, since
> registration is performed in the DSA setup path.

Looking at the setup code, is there anything undoing what
rtl8366rb_setup_cascaded_irq() does?

This patch however loos O.K.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew