[PATCH v3][for 4.15] dmaengine: dmatest: move callback wait queue to thread context

[Adam Wallis]

On 11/17/2017 12:01 PM, Adam Wallis wrote:
> On 11/17/2017 10:57 AM, Dan Williams wrote:
>> On Fri, Nov 17, 2017 at 7:28 AM, Adam Wallis <awallis at codeaurora.org> wrote:
>>> On 11/17/2017 10:12 AM, Dan Williams wrote:
>>>> On Fri, Nov 17, 2017 at 6:11 AM, Adam Wallis <awallis at codeaurora.org> wrote:
>>>>> Commit adfa543e7314 ("dmatest: don't use set_freezable_with_signal()")
>>>>> introduced a bug (that is in fact documented by the patch commit text)
>>>>> that leaves behind a dangling pointer. Since the done_wait structure is
>>>>> allocated on the stack, future invocations to the DMATEST can produce
>>>>> undesirable results (e.g., corrupted spinlocks).
>>>>>
>>>>> Commit a9df21e34b42 ("dmaengine: dmatest: warn user when dma test times
>>>>> out") attempted to WARN the user that the stack was likely corrupted but
>>>>> did not fix the actual issue.
>>>>>
>>>>> This patch fixes the issue by pushing the wait queue and callback
>>>>> structs into the the thread structure. If a failure occurs due to time,
>>>>> dmaengine_terminate_all will force the callback to safely call
>>>>> wake_up_all() without possibility of using a freed pointer.
>>>>>
>>>>> Cc: stable at vger.kernel.org # 4.13.x: a9df21e: dmatest: Warn User
>>>>> Cc: stable at vger.kernel.org # 4.13.x
>>>>> Cc: stable at vger.kernel.org # 4.14.x
>>>>
>>>
>>> Sure - do you want me to remove them? I was just following the instructions on
>>> stable.
>>
>> It's not broken, just a note for next time.
>>
One last question - if all we need is Fixes and CC stable...how do we indicate a
dependency (for a cherry pick)?

Thanks


-- 
Adam Wallis
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.