Date: Tue, 27 Sep 2016 17:21:45 +0200
From: Greg KH <gregkh@linuxfoundation.org>
To: Aditya.Shankar@microchip.com
Cc: Ganesh.Krishna@microchip.com, nicolas.ferre@atmel.com,
        linux-wireless@vger.kernel.org, luisbg@osg.samsung.com
Subject: Re: staging: wilc1000: kernel Oops while opening the device
Message-ID: <20160927152145.GD4371@kroah.com> (sfid-20160927_172144_628113_FEBA3865)
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On Mon, Sep 26, 2016 at 05:17:37AM +0000, Aditya.Shankar@microchip.com wrote:
> On Friday 23 September 2016 08:37 PM, Greg KH wrote:
> > On Fri, Sep 23, 2016 at 01:17:08PM +0000, Aditya.Shankar@microchip.com wrote:
> >> On Thursday 22 September 2016 06:04 PM, Ganesh Krishna - I00112 wrote:
> >>>> -----Original Message-----
> >>>> From: Greg Kroah-Hartman [mailto:gregkh@linuxfoundation.org] 
> >>>> Sent: Monday, September 19, 2016 7:12 PM
> >>>> To: Nicolas Ferre
> >>>> Cc: linux-wireless@vger.kernel.org; Aditya Shankar - I16078; Ganesh Krishna - I00112; luisbg@osg.samsung.com
> >>>> Subject: Re: staging: wilc1000: kernel Oops while opening the device
> >>>>
> >>>> On Mon, Sep 19, 2016 at 02:06:02PM +0200, Nicolas Ferre wrote:
> >>>>> Hi all,
> >>>>>
> >>>>> While using the wilc1000 driver with latest 4.8-rc7, I have 
> >>>>> difficulties to open the device and actually use it as I have this 
> >>>>> kernel Oops right after the loading of the firmware (wilc1003_firmware.bin).
> >>>>>
> >>>>> If I revert back the driver to its 
> >>>>> b9811891a9f60ca9c314dcab3244c65930c4cf37 state, it works okay. I did 
> >>>>> this because I tend to think that it might be related to the latest move on this driver to "completion" or "work queues".
> >>>>> It seems to be a regression from 4.7.
> >>>>
> >>>> Ick, not good at all.
> >>>>
> >>>> Any chance you can run 'git bisect' to see if you can find the offending patch?
> >>>>
> >>>> I thought the maintainers were testing this driver over time :(
> >>>
> >>>> thanks,
> >>>>
> >>>> greg k-h
> >>>
> >>> Ick indeed. Maintainers are on it full time. Thank you very much for the flag. While I am only reporting activity, hope to have results soon.
> >>> Regards,
> >>> ganesh k 
> >>>
> >> Hi All,
> >>
> >> bisecting changes on the wilc1000 host driver, I find that this problem seems to occur after the below change. 
> >> As of now, I only know the where and not the why. So I will continue to figure out why this happens.
> >>
> >> commit 2518ac59eb27ed003c5a97e8f9588adafdfe4a8a
> >> Author: Binoy Jayan <binoy.jayan@linaro.org>
> >> Date:   Thu Jun 23 11:11:51 2016 +0530
> >>
> >>     staging: wilc1000: Replace kthread with workqueue for host interface
> >>     
> >>     Deconstruct the kthread / message_queue logic, replacing it with
> >>     create_singlethread_workqueue() / queue_work() setup, by adding a
> >>     'struct work_struct' to 'struct host_if_msg'. The current kthread
> >>     hostIFthread() is converted to a work queue helper with the name
> >>     'host_if_work'.
> > 
> > So if you revert this, it works?
> > 
> > If so, let us know and I will gladly revert it, as breaking things is
> > not ok.
> > 
> > thanks,
> > 
> > greg k-h
> > 
> Unfortunately no. We will have to revert this commit and the one submitted after this. 
> The commit a5c84b2 after 2518ac5 is heavily reliant on its parent 2518ac5.
> 
> Note that reverting 2518ac5 throws up a couple of minor merge conflicts which can be
> resolved by dropping changes in HEAD and retaining the parent commit of 2518ac5.
> With this, the crash is not seen anymore.

Can you send me a patch, or series of patches, that does all of this so
I know I get it correct?

thanks,

greg k-h