tcp: Fix data-races around sysctl_tcp_l3mdev_accept.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2149949


Upstream Status: linux.git

commit 08a75f10
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date:   Wed Jul 13 13:51:59 2022 -0700

    tcp: Fix data-races around sysctl_tcp_l3mdev_accept.

    While reading sysctl_tcp_l3mdev_accept, it can be changed concurrently.
    Thus, we need to add READ_ONCE() to its readers.

    Fixes: 6dd9a14e ("net: Allow accepted sockets to be bound to l3mdev domain")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Guillaume Nault <gnault@redhat.com>