ret = ioctl(sock, SIOCGSTAMPNS, &tv); return -1

[TirelessMan]

I am going to use libpingpong PoC in my Android nexus 5 device,

I have developed an apk file and integrate libpingpong native codes(exploit.c and pingpong.c c function) in my native part of the application.
When I run my application, I can not get the root access. I trace my application and my codes and find that the ioctl does not return 1 and only return -1 which is not good.

What is the problem and how can I resolve that? Can anyone help me Please?

Thanks.