Merge branch 'net-fix-uaf-of-sk_dst_get-sk-dev'

Kuniyuki Iwashima says:

====================
net: Fix UAF of sk_dst_get(sk)->dev.

syzbot caught use-after-free of sk_dst_get(sk)->dev,
which was not fetched under RCU nor RTNL. [0]

Patch 1 ~ 5, 7 fix UAF in smc, tcp, ktls, mptcp
Patch 6 fixes dst ref leak in mptcp

[0]: https://lore.kernel.org/68c237c7.050a0220.3c6139.0036.GAE@google.com

v1: https://lore.kernel.org/20250911030620.1284754-1-kuniyu@google.com
====================

Link: https://patch.msgid.link/20250916214758.650211-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>