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Date: Mon, 15 Jan 2024 04:45:21 +0100
From: Andrew Lunn <andrew@lunn.ch>
To: Kunwu Chan <chentao@kylinos.cn>
Cc: hkallweit1@gmail.com, linux@armlinux.org.uk, davem@davemloft.net,
	edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
	f.fainelli@gmail.com, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] net: phy: Fix possible NULL pointer dereference
 issues caused by phy_attached_info_irq
Message-ID: <bd80fc69-d334-4b69-8ba3-3b2b86e1fd84@lunn.ch>
References: <20240112095724.154197-1-chentao@kylinos.cn>
 <627c9558-04df-43a6-b6e4-a13f24a8bc1d@lunn.ch>
 <b71c5e28-2dbe-48c8-ab92-e1dad9d6f2e4@kylinos.cn>
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> > Here, i would just skip the print and continue with the reset of the
> > function. The print is just useful information, its not a big problem
> > if its not printed. However, if this function does not complete, the
> > network interface is likely to be dead.
> Thanks for the reminder.
> The second part doesn't look so perfect, can we just print an empty string
> when the irq_str is empty?
> 
> --- a/drivers/net/phy/phylink.c
> +++ b/drivers/net/phy/phylink.c
> @@ -1886,7 +1886,7 @@ static int phylink_bringup_phy(struct phylink *pl,
> struct phy_device *phy,
>         irq_str = phy_attached_info_irq(phy);
>         phylink_info(pl,
>                      "PHY [%s] driver [%s] (irq=%s)\n",
> -                    dev_name(&phy->mdio.dev), phy->drv->name, irq_str);
> +                    dev_name(&phy->mdio.dev), phy->drv->name, irq_str ?
> irq_str : "");
>         kfree(irq_str);

That is O.K, or skip the whole phylink_info().

     Andrew