v3d: Crash mitigation

Trade a crash in v3d_irq for a warning. This is just a temporary
sticking plaster over the wound - proper surgery is required.

Link: #6624

Signed-off-by: Phil Elwell <[email protected]>

Author: pelwell

drivers/gpu/drm/v3d/v3d_irq.c

@@ -113,13 +113,15 @@ v3d_irq(int irq, void *arg)
 	}
 
 	if (intsts & V3D_INT_FRDONE) {
-		struct v3d_fence *fence =
-			to_v3d_fence(v3d->render_job->base.irq_fence);
-
-		v3d_job_update_stats(&v3d->render_job->base, V3D_RENDER);
-		trace_v3d_rcl_irq(&v3d->drm, fence->seqno);
-		dma_fence_signal(&fence->base);
-		v3d->render_job = NULL;
+		if (!WARN_ON(!v3d->render_job)) {
+			struct v3d_fence *fence =
+				to_v3d_fence(v3d->render_job->base.irq_fence);
+
+			v3d_job_update_stats(&v3d->render_job->base, V3D_RENDER);
+			trace_v3d_rcl_irq(&v3d->drm, fence->seqno);
+			dma_fence_signal(&fence->base);
+			v3d->render_job = NULL;
+		}
 		status = IRQ_HANDLED;
 	}