can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock

mainline inclusion
from mainline-v6.8-rc5
commit 6cdedc18ba7b9dacc36466e27e3267d201948c8d
category: bugfix
bugzilla: 189774, https://gitee.com/src-openeuler/kernel/issues/I9E2GX
CVE: CVE-2023-52638

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6cdedc18ba7b9dacc36466e27e3267d201948c8d



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

The following 3 locks would race against each other, causing the
deadlock situation in the Syzbot bug report:

- j1939_socks_lock
- active_session_list_lock
- sk_session_queue_lock

A reasonable fix is to change j1939_socks_lock to an rwlock, since in
the rare situations where a write lock is required for the linked list
that j1939_socks_lock is protecting, the code does not attempt to
acquire any more locks. This would break the circular lock dependency,
where, for example, the current thread already locks j1939_socks_lock
and attempts to acquire sk_session_queue_lock, and at the same time,
another thread attempts to acquire j1939_socks_lock while holding
sk_session_queue_lock.

NOTE: This patch along does not fix the unregister_netdevice bug
reported by Syzbot; instead, it solves a deadlock situation to prepare
for one or more further patches to actually fix the Syzbot bug, which
appears to be a reference counting problem within the j1939 codebase.

Reported-by:  <syzbot+1591462f226d9cbf0564@syzkaller.appspotmail.com>
Signed-off-by: Ziqi Zhao <astrajoan@yahoo.com>
Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/all/20230721162226.8639-1-astrajoan@yahoo.com


[mkl: remove unrelated newline change]
Cc: stable@vger.kernel.org
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Conflicts:
	net/can/j1939/socket.c

Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com>