Re: Linux 4.2-rc1

[Shuah Khan <shuahkh@osg.samsung.com>]

On 07/09/2015 08:45 AM, Greg Kroah-Hartman wrote:
> On Thu, Jul 09, 2015 at 07:44:04AM -0600, Shuah Khan wrote:
>> On 07/09/2015 07:10 AM, Shuah Khan wrote:
>>> On 07/08/2015 09:17 PM, Linus Torvalds wrote:
>>>> On Wed, Jul 8, 2015 at 5:58 PM, Ming Lei <ming.lei@canonical.com> wrote:
>>>>> On Thu, Jul 9, 2015 at 1:29 AM, Linus Torvalds
>>>>> <torvalds@linux-foundation.org> wrote:
>>>>>> Also, it looks like you need to hold the "fw_lock" to even look at
>>>>>> that pointer, since the buffer can get reallocated etc.
>>>>>
>>>>> Yes, the above code with holding 'fw_lock' is right fix for the issue since
>>>>> sysfs read can happen anytime, and there is one race between firmware
>>>>> request abort and reading uevent of sysfs.
>>>>
>>>> So if fw_priv->buf is NULL, what should we do?
>>>>
>>>> Should we skip the TIMEOUT= and ASYNC= fields too?
>>>>
>>>> Something like the attached, perhaps?
>>>>
>>>> Shuah, how reproducible is this? Does this (completely untested) patch
>>>> make any difference?
>>>>
>>>
>>> Happened both times I booted 4.2-rc1 up, so I would say 100% so far.
>>> I will test with your patch and report results.
>>>
>>
>> Yes. This patch fixed the problem.
> 
> That's great, but what changed recently to cause this problem to happen?
> Any chance you can bisect to the problem commit?
> 

:) Starting bisect now. Thankfully I built 4.1.0 in this tree
which is good place to start. Let you know in a bit

-- Shuah


-- 
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh@osg.samsung.com | (970) 217-8978