pidns: deny CLONE_PARENT|CLONE_NEWPID combination
pidns: deny CLONE_PARENT|CLONE_NEWPID combination

CLONE_PARENT was used to implement an older threading model.  For
consistency with the CLONE_THREAD check in copy_pid_ns(), disable
CLONE_PARENT with CLONE_NEWPID, at least until the required semantics of
pid namespaces are clear.

Signed-off-by: Sukadev Bhattiprolu <2ac48ee9b8f6042694a5d86ef56b8e10fe5327d1@us.ibm.com>
Acked-by: Roland McGrath <0d270388f2f92757a5de0f4bd891d3b392c44c4f@redhat.com>
Acked-by: Serge Hallyn <dd6cacb2d07f0aa354aa6e74c149a3580e5a1db1@us.ibm.com>
Cc: Oren Laadan <e7c85e4eed8752928f49d0ac9021ffa41221accf@cs.columbia.edu>
Cc: Oleg Nesterov <20b70f0af00562e63758b9ee42012ecc96c58590@redhat.com>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs