sctp: fix potential deadlock on &net->sctp.addr_wq_lock

stable inclusion
from stable-v4.19.290
commit 0ad0e8b0cb0e28626ab6dffe3da883941b9cbc4b
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I8WZLA
CVE: CVE-2024-0639

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0ad0e8b0cb0e28626ab6dffe3da883941b9cbc4b



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[ Upstream commit 6feb37b3 ]

As &net->sctp.addr_wq_lock is also acquired by the timer
sctp_addr_wq_timeout_handler() in protocal.c, the same lock acquisition
at sctp_auto_asconf_init() seems should disable irq since it is called
from sctp_accept() under process context.

Possible deadlock scenario:
sctp_accept()
    -> sctp_sock_migrate()
    -> sctp_auto_asconf_init()
    -> spin_lock(&net->sctp.addr_wq_lock)
        <timer interrupt>
        -> sctp_addr_wq_timeout_handler()
        -> spin_lock_bh(&net->sctp.addr_wq_lock); (deadlock here)

This flaw was found using an experimental static analysis tool we are
developing for irq-related deadlock.

The tentative patch fix the potential deadlock by spin_lock_bh().

Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Fixes: 34e5b011 ("sctp: delay auto_asconf init until binding the first addr")
Acked-by: Xin Long <lucien.xin@gmail.com>
Link: https://lore.kernel.org/r/20230627120340.19432-1-dg573847474@gmail.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com>