On Tue, Sep 13, 2016 at 02:29:29PM -0700, Andy Lutomirski wrote:
> This will prevent a crash if get_wchan() runs after the task stack
> is freed.

I think I found some more stuff. Have a look at KSTK_EIP() and KSTK_ESP(), I think
they read from the saved userspace registers area at the top of the kernel stack?

Used on remote processes in:
  vma_is_stack_for_task() (via /proc/$pid/maps)
  do_task_stat() (/proc/$pid/stat)