[PATCH] dma_fence_array: Fix PENDING_ERROR leak in dma_fence_array_signaled()

[Christian König]

Am 29.11.21 um 13:46 schrieb Thomas Hellström:
> On Mon, 2021-11-29 at 13:33 +0100, Christian König wrote:
>> Am 29.11.21 um 13:23 schrieb Thomas Hellström:
>>> Hi, Christian,
>>>
>>> On Mon, 2021-11-29 at 09:21 +0100, Christian König wrote:
>>>> Am 29.11.21 um 08:35 schrieb Thomas Hellström:
>>>>> If a dma_fence_array is reported signaled by a call to
>>>>> dma_fence_is_signaled(), it may leak the PENDING_ERROR status.
>>>>>
>>>>> Fix this by clearing the PENDING_ERROR status if we return true
>>>>> in
>>>>> dma_fence_array_signaled().
>>>>>
>>>>> Fixes: 1f70b8b812f3 ("dma-fence: Propagate errors to dma-fence-
>>>>> array container")
>>>>> Cc: linaro-mm-sig at lists.linaro.org
>>>>> Cc: Christian König <ckoenig.leichtzumerken at gmail.com>
>>>>> Cc: Chris Wilson <chris at chris-wilson.co.uk>
>>>>> Signed-off-by: Thomas Hellström
>>>>> <thomas.hellstrom at linux.intel.com>
>>>> Reviewed-by: Christian König <christian.koenig at amd.com>
>>> How are the dma-buf / dma-fence patches typically merged? If i915
>>> is
>>> the only fence->error user, could we take this through drm-intel to
>>> avoid a backmerge for upcoming i915 work?
>> Well that one here looks like a bugfix to me, so either through
>> drm-misc-fixes ore some i915 -fixes branch sounds fine to me.
>>
>> If you have any new development based on that a backmerge of the -
>> fixes
>> into your -next branch is unavoidable anyway.
> Ok, I'll check with Joonas if I can take it through
> drm-intel-gt-next, since fixes are cherry-picked from that one. Patch
> will then appear in both the -fixes and the -next branch.

Well exactly that's the stuff Daniel told me to avoid :)

But maybe your i915 workflow is somehow better handling that than the 
AMD workflow.

Christian.

>
> Thanks,
> /Thomas
>
>
>> Regards,
>> Christian.
>>
>>> /Thomas
>>>
>>>
>>>>> ---
>>>>>     drivers/dma-buf/dma-fence-array.c | 6 +++++-
>>>>>     1 file changed, 5 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/dma-buf/dma-fence-array.c b/drivers/dma-
>>>>> buf/dma-fence-array.c
>>>>> index d3fbd950be94..3e07f961e2f3 100644
>>>>> --- a/drivers/dma-buf/dma-fence-array.c
>>>>> +++ b/drivers/dma-buf/dma-fence-array.c
>>>>> @@ -104,7 +104,11 @@ static bool
>>>>> dma_fence_array_signaled(struct
>>>>> dma_fence *fence)
>>>>>     {
>>>>>           struct dma_fence_array *array =
>>>>> to_dma_fence_array(fence);
>>>>>     
>>>>> -       return atomic_read(&array->num_pending) <= 0;
>>>>> +       if (atomic_read(&array->num_pending) > 0)
>>>>> +               return false;
>>>>> +
>>>>> +       dma_fence_array_clear_pending_error(array);
>>>>> +       return true;
>>>>>     }
>>>>>     
>>>>>     static void dma_fence_array_release(struct dma_fence *fence)
>