This means an mmap system call failed. Though unfortunately the simulator tells you the syscall failed but doesn’t give you errno, so you can’t tell why it failed. I’d suspect an out-of-memory error as the first choice, maybe you need more simulated memory if you are trying to mmap something large. You might want to modify the simulator to print errno, or run it under the debugger so you can view errno when the syscall fails to get a better idea of what is going wrong.