if BTI is enabled, the first instruction encountered after an indirect jump must be a special BTI instruction
from here
I downloaded Ubuntu for arm64 (jammy-desktop-arm64.iso) and decided to check if there are some functions with don`t contain BTI c at start
17804 such functions. System.map-5.15.0-53-generic contains 62819 functions in total. Next I just intersected them with exported - 1269
This is obvious bug - maybe in gcc (Ubuntu 11.2.0-19ubuntu1) 11.2.0
at least some of this functions are really important - like register_ftrace_function