Oh no, Linux kernel 6.9 is chaotically adding 16 extra bytes to the stack! 
Quick, blame Fred—whoever he is—for this unspeakable horror. 
Ubuntu 24.04 users can now enjoy an unparalleled #debugging experience as they discover the joy of dealing with "garbage" data. 
https://tanelpoder.com/posts/ebpf-pt-regs-error-on-linux-blame-fred/ #LinuxKernel #Linux6.9 #Ubuntu2404 #Chaos #GarbageData #HackerNews #ngated
tanelpoder.comWhen eBPF task->stack->pt_regs reads return garbage on the latest Linux kernels, blame Fred! - Tanel Poder ConsultingTLDR; Starting from Linux kernel version 6.9 on x86_64, there’s a new config option CONFIG_X86_FRED enabled and it adds 16 bytes to the starting point of a task’s kernel stack area, so you’ll need to account for this extra padding in your “raw” kernel stack & pt_regs lookup code.
Introduction I’ve been using Ubuntu 24.04 as my main eBPF development and testing platform without issues since its release. It is shipped with Linux kernel version 6. - Linux, Oracle, SQL performance tuning and troubleshooting - consulting & training.
