Parameter-Efficient Fine-Tuning (PEFT), especially Low-Rank Adaptation (LoRA), has emerged as a promising approach to fine-tuning large language models(LLMs) while reducing computational and memory overhead. However, LoRA assumes a uniform rank r for each incremental matrix, not accounting for the varying significance of weight matrices across different modules and layers. AdaLoRA leverages Singular Value Decomposition (SVD) to parameterize updates and employs pruning of singular values to introduce dynamic rank allocation, thereby enhancing adaptability. However, during the training process, it often encounters issues of slow convergence speed and high computational overhead. To address this issue, we propose HyperAdaLoRA, a novel framework that accelerates the convergence of AdaLoRA by leveraging a hypernetwork. Instead of directly optimizing the components of Singular Value Decomposition (P, 𝛬, Q), HyperAdaLoRA employs a hypernetwork based on attention mechanisms to dynamically generate these parameters. By pruning the outputs of the hypernetwork that generates the singular values, dynamic rank allocation is achieved. Comprehensive experiments on various datasets and models demonstrate that our method achieves faster convergence without sacrificing performance. Moreover, our method generalizes well to other LoRA-based approaches, highlighting its strong generalization capability.

With the increasingly deep integration of large language models (LLMs) across diverse domains, the effectiveness of their safety mechanisms is encountering severe challenges. Currently, jailbreak attacks based on prompt engineering, which induce models to generate potentially harmful content, have become a major security threat. However, existing methods primarily rely on black-box manipulation of prompt templates, resulting in high costs and poor generalizability. To break through the bottleneck, this study reveals the potential impact of the generation of LLMs on safety for the first time that Defense Threshold Decay (DTD) phenomena: as benign content generation increases, the model’s attention to input instructions progressively diminishes. Building on this insight, we propose the Sugar-Coated Poison (SCP) attack paradigm, using a “semantic reversal” strategy, where benign inputs that are opposite in meaning to malicious intent are crafted to induce the model into a safety response mode. When the defense threshold decays, an adversarial reasoning mechanism easily bypasses safety mechanisms. Experiments show SCP outperforms existing baselines. For defense, we propose Part-of-Speech Defense (POSD), leveraging verb-noun dependencies for syntactic analysis to enhance robustness and security of LLMs. Our code is available at https://anonymous.4open.science/r/SCP-9092.