linux-kernel - Re: [PATCH] net: phy: Don't call phy_resume if phy_init

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Message-ID: <CAGVrzca6WKSS9VxhLhs=n398exRxAKs4FK9-2DEc=srYNmx6-w@mail.gmail.com>
Date:	Wed, 14 May 2014 13:21:52 -0700
From:	Florian Fainelli <f.fainelli@...il.com>
To:	Guenter Roeck <linux@...ck-us.net>
Cc:	netdev <netdev@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] net: phy: Don't call phy_resume if phy_init_hw failed

2014-05-14 13:12 GMT-07:00 Guenter Roeck <linux@...ck-us.net>:
> After the call to phy_init_hw failed in phy_attach_direct, phy_detach is called
> to detach the phy device from its network device. If the attached driver is a
> generic phy driver, this also detaches the driver. Subsequently phy_resume
> is called, which assumes without checking that a driver is attached to the
> device. This will result in a crash such as
>
> Unable to handle kernel paging request for data at address 0xffffffffffffff90
> Faulting instruction address: 0xc0000000003a0e18
> Oops: Kernel access of bad area, sig: 11 [#1]
> ...
> NIP [c0000000003a0e18] .phy_attach_direct+0x68/0x17c
> LR [c0000000003a0e6c] .phy_attach_direct+0xbc/0x17c
> Call Trace:
> [c0000003fc0475d0] [c0000000003a0e6c] .phy_attach_direct+0xbc/0x17c (unreliable)
> [c0000003fc047670] [c0000000003a0ff8] .phy_connect_direct+0x28/0x98
> [c0000003fc047700] [c0000000003f0074] .of_phy_connect+0x4c/0xa4
>
> Only call phy_resume if phy_init_hw was successful.
>
> Signed-off-by: Guenter Roeck <linux@...ck-us.net>

Acked-by: Florian Fainelli <f.fainelli@...il.com>

Thanks!

> ---
> Another option might be to check in phy_detach if a driver is attached
> to the device.
>
>  drivers/net/phy/phy_device.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index 0ce6066..4987a1c 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -614,8 +614,8 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
>         err = phy_init_hw(phydev);
>         if (err)
>                 phy_detach(phydev);
> -
> -       phy_resume(phydev);
> +       else
> +               phy_resume(phydev);
>
>         return err;
>  }
> --
> 1.9.1
>



-- 
Florian
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