On Thu, 23 Sep 2021 16:31:05 -0700 Kees Cook <keescook@xxxxxxxxxxxx> wrote: > The /proc/$pid/wchan file has been broken by default on x86_64 for 4 > years now[1]. [1] is hard to decrypt. I think it would be better if this changelog were to describe the problem directly, completely and succinctly? > As this remains a potential leak of either kernel > addresses (when symbolization fails) or limited observation of kernel > function progress, just remove the contents for good. > > Unconditionally set the contents to "0" and also mark the wchan > field in /proc/$pid/stat with 0. > > This leaves kernel/sched/fair.c as the only user of get_wchan(). But > again, since this was broken for 4 years, was this profiling logic > actually doing anything useful? Agree that returning a hard-wired "0\n" is the way to go.
