Merge branch 'udp-fix-two-integer-overflows-when-sk-sk_rcvbuf-is-close-to-int_max'

Kuniyuki Iwashima says:

====================
udp: Fix two integer overflows when sk->sk_rcvbuf is close to INT_MAX.

I got a report that UDP mem usage in /proc/net/sockstat did not
drop even after an application was terminated.

The issue could happen if sk->sk_rmem_alloc wraps around due
to a large sk->sk_rcvbuf, which was INT_MAX in our case.

The patch 2 fixes the issue, and the patch 1 fixes yet another
overflow I found while investigating the issue.

v3: https://lore.kernel.org/20250327202722.63756-1-kuniyu@amazon.com
v2: https://lore.kernel.org/20250325195826.52385-1-kuniyu@amazon.com
v1: https://lore.kernel.org/20250323231016.74813-1-kuniyu@amazon.com
====================

Link: https://patch.msgid.link/20250401184501.67377-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>