> >> I have not seen any activity on that in a long time. IIRC, Julien quit RedHat. > >> I don't know if anyone else has taken over this work in RedHat. > >> > >> Sorry, I don't have any more information. > >> > >> Madhavan > > > > Thanks for your information. > > > > By the way, I'm considering test code for arch_stack_walk_reliable(). > > Specifically, I apply Suraj's patch to enable livepatch, and added a function > > that sleeps between SYM_CODE_START and SYM_CODE_END, then livepatch > > checks if the task has an unreliable stack. > > For now my internal test code working correctly, but my Kconfig excludes > > STACK_VALIDATION dependency. > > > > It seems that objtool will not be enabled yet, so I would like to test it easier. > > If you are already testing with this patch, could you tell me how to do it? > > > > > > For now, I have an instrumented kernel that directly invokes arch_stack_walk_reliable() > from various places in the kernel (interrupt handlers, exception handlers, ftrace entry, > kprobe handler, etc). I also have a test driver to induce conditions like null pointer > dereference. I use this to test different cases where arch_stack_walk_reliable() should > return an error. That's good to know, thanks. > > As for livepatch testing, I have enhanced objtool and the kernel so the frame pointer can > be validated dynamically rather than statically. I have tested various different livepatch > selftests successfully. I have also written my own livepatch tests to add to the selftests. > I am currently working on preparing an RFC patch series for review. Basically, this series > implements STACK_VALIDATION in a different way. > > I plan to publish my work soon (hopefully Feb 2022). I was going to do in December. However, > my workload in Microsoft did not permit me to do that. I am also planning to set up a github > repo so people can try out my changes, if they are interested. > > So, stay tuned. > > Madhavan I'm very interested, so I would to be happy if you could tell me when the github repo is set up. Thanks again, Keiya
