mptcp: pm: use _rcu variant under rcu_read_lock

stable inclusion
from stable-v6.6.63
commit 3bc4569a727d776819c2fd413098882798974aae
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IBI1RP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3bc4569a727d776819c2fd413098882798974aae



--------------------------------

commit db3eab8110bc0520416101b6a5b52f44a43fb4cf upstream.

In mptcp_pm_create_subflow_or_signal_addr(), rcu_read_(un)lock() are
used as expected to iterate over the list of local addresses, but
list_for_each_entry() was used instead of list_for_each_entry_rcu() in
__lookup_addr(). It is important to use this variant which adds the
required READ_ONCE() (and diagnostic checks if enabled).

Because __lookup_addr() is also used in mptcp_pm_nl_set_flags() where it
is called under the pernet->lock and not rcu_read_lock(), an extra
condition is then passed to help the diagnostic checks making sure
either the associated spin lock or the RCU lock is held.

Fixes: 86e39e04 ("mptcp: keep track of local endpoint still available for each msk")
Cc: stable@vger.kernel.org
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20241112-net-mptcp-misc-6-12-pm-v1-3-b835580cefa8@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Wen Zhiwei <wenzhiwei@kylinos.cn>