Scalpel: Automotive Deep Learning Framework Testing via Assembling Model Components

Deep learning (DL) plays a key role in autonomous driving systems. DL models support perception modules, equipped with tasks such as object detection and sensor fusion. These DL models enable vehicles to process multi-sensor inputs to understand complex surroundings. Deploying DL models in autonomous driving systems faces stringent challenges, including real-time processing, limited computational resources, and strict power constraints. To address these challenges, automotive DL frameworks (e.g., PaddleInference) have emerged to optimize inference efficiency. However, these frameworks encounter unique quality issues due to their more complex deployment environments, such as crashes stemming from limited scheduled memory and incorrect memory allocation. Unfortunately, existing DL framework testing methods fail to detect these quality issues due to the failure in deploying generated test input models, as these models lack three essential capabilities: (1) multi-input/output tensor processing, (2) multi-modal data processing, and (3) multi-level data feature extraction. These capabilities necessitate specialized model components, which existing testing methods neglect during model generation. To bridge this gap, we propose Scalpel, an automotive DL frameworks testing method that generates test input models at the model component level. Scalpel generates models by assembling model components (heads, necks, backbones) to support capabilities required by autonomous driving systems. Specifically, Scalpel maintains and updates a repository of model components, generating test inputs by selecting, mutating, and assembling them. Successfully generated models are added back to enrich the repository. Newly generated models are then deployed within the autonomous driving system to test automotive DL frameworks via differential testing. The experimental results demonstrate that Scalpel outperforms existing methods in both effectiveness and efficiency. In Apollo, Scalpel detects 16 crashes and 21 NaN & inconsistency bugs. All detected bugs have been reported to open-source communities, with 10 crashes confirmed. Scalpel achieves 27.44 × and 8.5 × improvements in model generation efficiency and bug detection efficiency. Additionally, Scalpel detects nine crashes and 16 NaN & inconsistency bugs in Autoware, which shows its excellent generalization.