Description of problem: Reported by Tavis Ormandy and Julien Tinnes. The SOCKOPSWRAP macro from include/linux/net.h doesn't initialise the sendpage operation in the protoops structure correctly. Leading to a kernel NULL pointer dereference, and thus a local privilege escalation.
Acknowledgements:
Red Hat would like to thank Tavis Ormandy and Julien Tinnes of the Google Security Team for responsibly reporting this flaw.