The Code Rabbit link is about software in general, not the Linux kernel in particular. In many ways the Linux kernel is an outlier among software projects. When it comes to LLMs, I don’t expect devs will be using lower standards for code reviews in quality, while some other teams definitely are doing light “LGTM” reviews of AI code.
The second link expresses a lot of concerns about plagiarism by AI. Certainly related care needs to taken for contributions to the Linux kernel. As far as I could tell, no specific cases of plagiarized code in the kernel were cited.