Thank @0xab for answering this question. Actually I hold the same opinion as @0xab. Those "non-adversarial non-attack" happens sometimes and there also exist adversarial attacks where adversary intentionally craft some pictures to fool the system. In some cases, the system already achieves a pretty high performance and generalize very well on various datasets but they may fail on adversarial images. For example, attackers can put some carefully-crafted stickers on the STOP sign and the self-driving car will give wrong predictions. The existence of adversarial attacks poses great challenges in applying deep learning model in safety-critical scenarios.

Both non-adversarial non-attack and adversarial attack reflect the vulnerability of the current deep learning models. Thus it is of great significance to study these problem and find countermeasures against those attacks.