> - Is using the whole 8 bytes right for the estimate? Pushing the stack pointer is the first instruction in the prologue and it's literally 1 byte. Epilogue is

> - Is using the whole 8 bytes right for the estimate? Pushing the stack pointer is the first instruction in the prologue and it's literally 1 byte. Epilogue is symmetrical. I believe it's because of the landing pad for Control Flow Integrity which basically all functions now need. Grabbing main() from a random program on Fedora (which uses frame pointers): 0000000000007000 <main>: 7000: f3 0f 1e fa endbr64 ; landing pad 7004: 55 push %rbp ; set up frame pointer 7005: 48 89 e5 mov %rsp,%rbp It's not much of an issue in practice as the stack trace will still be nearly correct, enough for you to identify the problematic area of the code. > - Shadow stacks are cool but aren't they limited to a fixed number of entries? What if you have a deeper stack? Yes shadow stacks are limited to 32 entries on the most recent Intel CPUs (and as little as 4 entries on very old ones). However they are basically cost free so that's a big advantage. I think SFrame is a sensible middle ground here. It's saner than DWARF and has a long history of use in the kernel so we know it will work.