The tale of a single register value

This post details a deep dive into debugging a Linux kernel crash (kernel oops) in the ipv4 stack, triggered by a single network packet. It meticulously traces the crash to the `skb_gso_transport_seglen()` function, analyzing the assembly code and register values to pinpoint the cause: an invalid memory access when calculating the inner TCP header length for encapsulated packets. The investigation highlights the challenges of low-level kernel debugging and the importance of understanding packet structures and memory management in network stack operations.