If no console is configured, then the following code gets executed:
int conf_parse_config(void)
{
...
char *fallback = FALLBACK_SHELL;
...
tty_register(fallback);
...
}
int tty_register(char *line)
{
...
cmd = strtok(line, " ");
...
}
FALLBACK_SHELL is constant character array and strtok tries to modify
the first argument, which causes a crash.