Get user stackpointer from task_struct

Hi, I have kcore and I want to get userspace backtrace from kcore. I looked at some macro <https://www.kernel.org/doc/Documentation/kdump/gdbmacros.txt> but still this is just giving me kernel backtrace only. What I want is userspace backtrace. Good news is I have pointer to task_struct. task_struct->thread->sp (Kernel stack pointer) task_struct->thread->usersp (user stack pointer) but this is junk My question is how to get userspace backtrace (or stack pointer) from kcore or task_struct ? - Shirish