tcp: Fix a data-race around sysctl_tcp_probe_threshold.

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


Upstream Status: linux.git

commit 92c0aa41
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date:   Wed Jul 13 13:52:04 2022 -0700

    tcp: Fix a data-race around sysctl_tcp_probe_threshold.

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

    Fixes: 6b58e0a5 ("ipv4: Use binary search to choose tcp PMTU probe_size")
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>