From: Xiaoming Ni <nixiaoming@huawei.com>
To: <adobriyan@gmail.com>, <akpm@linux-foundation.org>,
<anna.schumaker@netapp.com>, <arjan@linux.intel.com>,
<bfields@fieldses.org>, <chuck.lever@oracle.com>,
<davem@davemloft.net>, <gregkh@linuxfoundation.org>,
<jlayton@kernel.org>, <luto@kernel.org>, <mingo@kernel.org>,
<Nadia.Derbey@bull.net>, <paulmck@linux.vnet.ibm.com>,
<semen.protsenko@linaro.org>, <stable@kernel.org>,
<stern@rowland.harvard.edu>, <tglx@linutronix.de>,
<torvalds@linux-foundation.org>,
<trond.myklebust@hammerspace.com>, <viresh.kumar@linaro.org>,
<vvs@virtuozzo.com>
Cc: <alex.huangjianhui@huawei.com>, <dylix.dailei@huawei.com>,
<nixiaoming@huawei.com>, <linux-kernel@vger.kernel.org>,
<linux-nfs@vger.kernel.org>, <netdev@vger.kernel.org>
Subject: [PATCH v3 0/3] kernel/notifier.c: avoid duplicate registration
Date: Wed, 10 Jul 2019 11:09:07 +0800 [thread overview]
Message-ID: <1562728147-30251-1-git-send-email-nixiaoming@huawei.com> (raw)
Registering the same notifier to a hook repeatedly can cause the hook
list to form a ring or lose other members of the list.
case1: An infinite loop in notifier_chain_register() can cause soft lockup
atomic_notifier_chain_register(&test_notifier_list, &test1);
atomic_notifier_chain_register(&test_notifier_list, &test1);
atomic_notifier_chain_register(&test_notifier_list, &test2);
case2: An infinite loop in notifier_chain_register() can cause soft lockup
atomic_notifier_chain_register(&test_notifier_list, &test1);
atomic_notifier_chain_register(&test_notifier_list, &test1);
atomic_notifier_call_chain(&test_notifier_list, 0, NULL);
case3: lose other hook test2
atomic_notifier_chain_register(&test_notifier_list, &test1);
atomic_notifier_chain_register(&test_notifier_list, &test2);
atomic_notifier_chain_register(&test_notifier_list, &test1);
case4: Unregister returns 0, but the hook is still in the linked list,
and it is not really registered. If you call notifier_call_chain
after ko is unloaded, it will trigger oops. if the system is
configured with softlockup_panic and the same hook is repeatedly
registered on the panic_notifier_list, it will cause a loop panic.
so. need add a check in in notifier_chain_register() to avoid duplicate
registration
v1:
* use notifier_chain_cond_register replace notifier_chain_register
v2:
* Add a check in notifier_chain_register() to avoid duplicate registration
* remove notifier_chain_cond_register() to avoid duplicate code
* remove blocking_notifier_chain_cond_register() to avoid duplicate code
v3:
* Add a cover letter.
Xiaoming Ni (3):
kernel/notifier.c: avoid duplicate registration
kernel/notifier.c: remove notifier_chain_cond_register()
kernel/notifier.c: remove blocking_notifier_chain_cond_register()
include/linux/notifier.h | 4 ----
kernel/notifier.c | 41 +++--------------------------------------
net/sunrpc/rpc_pipe.c | 2 +-
3 files changed, 4 insertions(+), 43 deletions(-)
--
1.8.5.6
next reply other threads:[~2019-07-10 3:09 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-10 3:09 Xiaoming Ni [this message]
2019-07-10 5:49 ` [PATCH v3 0/3] kernel/notifier.c: avoid duplicate registration Vasily Averin
2019-07-11 1:55 ` Nixiaoming
2019-07-11 13:57 ` Vasily Averin
2019-07-12 13:11 ` Xiaoming Ni
2019-07-12 14:07 ` gregkh
2019-07-14 2:45 ` Xiaoming Ni
2019-07-15 5:38 ` Vasily Averin
2019-07-16 2:00 ` Xiaoming Ni
2019-07-16 10:20 ` Vasily Averin
2019-07-16 14:07 ` Xiaoming Ni
2019-07-17 11:15 ` Vasily Averin
2019-09-10 3:57 ` Xiaoming Ni
2019-07-10 5:56 ` Greg KH
2019-07-11 1:32 ` Nixiaoming
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