add backtrace in CI when a core occurs
in CI, could you add this when a core occurs (better than catch segv) ulimit -c unlimited ==>> the core file will exist if the process is killed like in segv
in this case, in your python script, install gdb and run (and log in a file)
sudo gdb -ex bt -ex q ./lte-softmodem core
we will have a good post mortem trace