There are a number of functions which read ucontext_t* and where the parameters are unnecessarily non-const:

os::<os>::ucontext_get_pc
os::<os>::ucontext_get_sp
os::<os>::ucontext_get_fp
os::print_context
os::print_register_info
os::fetch_frame_from_context
os::abort

For all these functions, context should be passed in as const pointer.