Return-Path: MIME-Version: 1.0 In-Reply-To: <4A705604.3040807@hartkopp.net> References: <4A6AD807.6060706@hartkopp.net> <20090725115011.7ddf8d00@lxorguk.ukuu.org.uk> <1248520053.28545.156.camel@violet> <20090725131046.0f076f37@lxorguk.ukuu.org.uk> <20090727095904.GA5442@darkstar> <4A6D8BA3.3030601@hartkopp.net> <4A6D91D7.6030204@hartkopp.net> <20090727140736.GA1864@darkstar> <4A705604.3040807@hartkopp.net> Date: Thu, 30 Jul 2009 17:15:21 +0800 Message-ID: Subject: Re: tty_register_device NULL pointer dereference in 2.6.31-rc4 From: Dave Young To: Oliver Hartkopp Cc: Alan Cox , Marcel Holtmann , Linux Netdev List , linux-bluetooth@vger.kernel.org Content-Type: text/plain; charset=UTF-8 List-ID: On Wed, Jul 29, 2009 at 10:00 PM, Oliver Hartkopp wrote: > Dave Young wrote: >> On Mon, Jul 27, 2009 at 01:39:03PM +0200, Oliver Hartkopp wrote: >>> Oliver Hartkopp wrote: >>>> Dave Young wrote: >>>>> On Sat, Jul 25, 2009 at 01:10:46PM +0100, Alan Cox wrote: >>>>>>>> tty_register_device appears to have been called with a NULL pointer. Not >>>>>>>> sure why however. >>>>>>> if that is the pointer for the struct device, then that used to be fine >>>>>>> in the past. Not all RFCOMM device have a parent when they are created. >>>>>> The tty layer doesn't care about the struct device really. Nothing there >>>>>> has changed. The NULL passed appears to be the driver argument. >>>>> Agree with you, because in rfcomm_init, rfcomm thread run before tty initilized, the following patch may fix the problem. >>>>> oliver, could you verify it it fix your problem? >>>> Hi Dave, >>>> >>>> i get this problem really seldom on my Laptop and i did not manage to get a >>>> reproducible Oops of that problem. >>>> >>>> Anyway the code you are pointing to seems to have a problem and your added >>>> error handling looks good to me - even if i don't know if the initializations >>>> can be reordered in that way. >>>> >>>> I'll try your patch, but it could take a *long* time to prove it right ;-) >>>> >>> Just FYI: >>> >>> Your patch compiled, the system booted without problems and nothing is broken >>> so far. I checked the BT, WLAN and BT dial-up with success. So it looks good >>> to me. >> >> Thanks for the testing. Marcel, could you take a look? > > Hi Dave, > > i got it again - even with your patch (that's why it's 2.6.31-rc4-dirty in the > attached screenshot). Weird, the oops occurs between sock init and tty init routines. Could you tell your bluez version and your configuration? -- Regards dave