sysctl: Fix data-races in proc_dou8vec_minmax().

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


Upstream Status: linux.git

commit 7dee5d77
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date:   Mon Jul 11 17:15:19 2022 -0700

    sysctl: Fix data-races in proc_dou8vec_minmax().

    A sysctl variable is accessed concurrently, and there is always a chance
    of data-race.  So, all readers and writers need some basic protection to
    avoid load/store-tearing.

    This patch changes proc_dou8vec_minmax() to use READ_ONCE() and
    WRITE_ONCE() internally to fix data-races on the sysctl side.  For now,
    proc_dou8vec_minmax() itself is tolerant to a data-race, but we still
    need to add annotations on the other subsystem's side.

    Fixes: cb944413 ("sysctl: add proc_dou8vec_minmax()")
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>