Re: Regression in inv_mpu6050: 4.6.0-rc5

Jonathan Cameron
2016-05-04T18:16:15Z

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

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