Re: Regression in inv_mpu6050: 4.6.0-rc5

[Jonathan Cameron <jic23@kernel.org>]

On 04/05/16 19:15, Jonathan Cameron wrote:
> 
> 
> On 4 May 2016 18:24:43 BST, Greg KH <gregkh@linuxfoundation.org> wrote:
>> On Wed, May 04, 2016 at 08:49:06AM +0100, Jonathan Cameron wrote:
>>> On 03/05/16 19:54, Crestez Dan Leonard wrote:
>>>> On 05/01/2016 10:58 PM, Jonathan Cameron wrote:
>>>>> On 27/04/16 16:56, One Thousand Gnomes wrote:
>>>>>> On Tue, 26 Apr 2016 18:07:55 -0500
>>>>>> Michael Welling <mwelling@ieee.org> wrote:
>>>>>>
>>>>>>> On Tue, Apr 26, 2016 at 11:26:51PM +0100, One Thousand Gnomes
>> wrote:
>>>>>>>>
>>>>>>>> This now causes us to crash and burn on the ASUS T100TA
>> Baytrail/T
>>>>>>>> platforms
>>>>>>>>  
>>>>>>>
>>>>>>> I believe this regression has already been patched.
>>>>>>>
>>>>>>> Check the latest commits in linux-next.
>>>>>>>
>>>>>>>
>> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/log/drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c
>>>>>>>
>>>>>>> See if the latest patches fix your issue.
>>>>>>
>>>>>> It does - as this is a regression can we please get those fixes
>> into the
>>>>>> next -rc ?
>>>>>>
>>>>> I'm afraid I'm lost in this one - which patch caused the
>> regression and
>>>>> which one fixed it?  The only patches I can immediately see in
>> next
>>>>> both introduce and then squish a similar bug, but neither of them
>>>>> has hit Linus' tree yet.
>>>>>
>>>>> Or are we dealing with what was fixed in:
>>>>> c816d9e7 iio: imu: mpu6050: fix possible NULL dereferences
>>>>> I had understood that one as more hypothetical than real...
>>>>>
>>>>> Unfortunately I'm travelling and I suspect that means this will
>> only get
>>>>> in just after the release (so for 4.6.1) once I've confirmed which
>> fixes
>>>>> we actually need to backport.
>>>>>
>>>> Commit
>>>>     c816d9e7: iio: imu: mpu6050: fix possible NULL dereferences
>>>> Fixes:
>>>>     33da559f: iio: imu: mpu6050: add mpu6500 register settings
>>>>
>>>> As far as I can tell this crash will always happen when the device
>> is
>>>> probed via ACPI.
>>>
>>> Hi Greg,
>>>
>>> A quick heads up.
>>>
>>> Unfortunately this regression has come up whilst I'm travelling and
>>> don't have appropriate signing keys with me to do a pull request.
>>> Should be able to do one tomorrow evening as I'll back home.
>>>
>>> Turns out the 'possible' is quite common and causing a mess.
>>> Even better the fix actually has a fix as well... 
>>>
>>> Fastest option is probably a cherry pick of:
>>>
>>> c816d9e7: iio: imu: mpu6050: fix possible NULL dereferences
>>> 718ba46e: iio: imu: mpu6050: Fix name/chip_id when using ACPI
>>
>>>From where?
> Doh.
> 
> Both already in your staging-next. Confusion was over
> the seriousness of the issue so went via wrong route.
> 
>>
>>>
>>> I'll send you a pull request of my 
>>> togreg-in-a-hurry branch tomorrow.
>>>
>>> Sorry for these being so late in the cycle.
>>>
>>> Anyhow, run for train time. 
>>
>> You can always just send me patches, no need for it to always be a pull
>> request if you can't do that for some reason.
> 
> Good point, nothing like limited time to make one an idiot sometimes!
> 
> Jonathan
>>
>> thanks,
>>
>> greg k-h
> 
I've just sent a pull request in case if you want to grab it that way.

For reference the crash report is:
http://www.spinics.net/lists/linux-iio/msg24431.html

Thanks,

Jonathan