From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Duyck Subject: Re: [PATCH] dsa: Fix conversion from host device to mii bus Date: Fri, 17 Oct 2014 16:02:02 -0700 Message-ID: <54419FEA.4090207@redhat.com> References: <1413574258-21766-1-git-send-email-linux@roeck-us.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Florian Fainelli , Alexander Duyck , netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Guenter Roeck , "David S. Miller" Return-path: In-Reply-To: <1413574258-21766-1-git-send-email-linux@roeck-us.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 10/17/2014 12:30 PM, Guenter Roeck wrote: > Commit b4d2394d01bc ("dsa: Replace mii_bus with a generic host device") > replaces mii_bus with a generic host_dev, and introduces > dsa_host_dev_to_mii_bus() to support conversion from host_dev to mii_bus. > However, in some cases it uses to_mii_bus to perform that conversion. > Since host_dev is not the phy bus device but typically a platform device, > this fails and results in a crash with the affected drivers. > > BUG: unable to handle kernel NULL pointer dereference at (null) > IP: [] __mutex_lock_slowpath+0x75/0x100 > PGD 406783067 PUD 406784067 PMD 0 > Oops: 0002 [#1] SMP > ... > Call Trace: > [] ? pick_next_task_fair+0x61b/0x880 > [] mutex_lock+0x23/0x37 > [] mdiobus_read+0x34/0x60 > [] __mv88e6xxx_reg_read+0x8a/0xa0 > [] mv88e6xxx_reg_read+0x4c/0xa0 > > Fixes: b4d2394d01bc ("dsa: Replace mii_bus with a generic host device") > Cc: Alexander Duyck > Signed-off-by: Guenter Roeck > --- The fix looks good to me. Acked-by: Alexander Duyck