Merge branch 'mptcp-fix-sockopt-crash-and-lockdep-splats'

Florian Westphal says:

====================
mptcp: fix sockopt crash and lockdep splats

Christoph Paasch reported a few bugs and lockdep splats triggered by
syzkaller.

One patch fixes a crash in set/getsockopt.
Two patches fix lockdep splats related to the order in which RTNL
and socket lock are taken.

Last patch fixes out-of-bounds access when TCP syncookies are used.

Change since last iteration on mptcp-list:
 - add needed refcount in patch 2
 - call tcp_get/setsockopt directly in patch 2

 Other patches unchanged except minor amends to commit messages.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>