[Intel-gfx] [PATCH 2/3] drm/i915: Never return 0 on timeout when retiring requests

[Das, Nirmoy]

Looks very relevant to  our recent hangcheck failures.


Acked-by: Nirmoy Das <nirmoy.das at intel.com>

On 11/16/2022 12:25 PM, Janusz Krzysztofik wrote:
> Users of intel_gt_retire_requests_timeout() expect 0 return value on
> success.  However, we have no protection from passing back 0 potentially
> returned by dma_fence_wait_timeout() on timeout.
>
> Replace 0 with -ETIME before using timeout as return value.
>
> Fixes: f33a8a51602c ("drm/i915: Merge wait_for_timelines with retire_request")
> Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik at linux.intel.com>
> Cc: stable at vger.kernel.org # v5.5+
> ---
>   drivers/gpu/drm/i915/gt/intel_gt_requests.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
> index ccaf2fd80625b..ac6b2b1861397 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
> @@ -213,6 +213,9 @@ out_active:	spin_lock(&timelines->lock);
>   	list_for_each_entry_safe(tl, tn, &free, link)
>   		__intel_timeline_free(&tl->kref);
>   
> +	if (!timeout)
> +		timeout = -ETIME;
> +
>   	if (flush_submission(gt, timeout)) /* Wait, there's more! */
>   		active_count++;
>