From: Nixiaoming <nixiaoming@huawei.com>
To: Greg KH <gregkh@linuxfoundation.org>
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Subject: RE: [PATCH v3 0/3] kernel/notifier.c: avoid duplicate registration
Date: Thu, 11 Jul 2019 01:32:57 +0000 [thread overview]
Message-ID: <E490CD805F7529488761C40FD9D26EF12AC9D039@dggemm507-mbx.china.huawei.com> (raw)
In-Reply-To: <20190710055628.GB5778@kroah.com>
On Wed, July 10, 2019 1:56 PM Greg KH wrote:
>On Wed, Jul 10, 2019 at 11:09:07AM +0800, Xiaoming Ni wrote:
>> Registering the same notifier to a hook repeatedly can cause the hook
>> list to form a ring or lose other members of the list.
>
>Then don't do that :)
>
Duplicate registration is checked and exited in notifier_chain_cond_register()
Duplicate registration was checked in notifier_chain_register() but only
the alarm was triggered without exiting. added by commit 831246570d34692e
("kernel/notifier.c: double register detection")
This patch is similar to commit 8312465 and notifier_chain_cond_register(),
with actual prevention for such behaviour, which I think is necessary to
avoid the formation of a linked list ring.
>Is there any in-kernel users that do do this? If so, please just fix
>them.
>
Notifier_chain_register() is not a hotspot path.
Adding a check here can make the kernel more stable.
Thanks
Xiaoming Ni
>thanks,
>
>greg k-h
>
prev parent reply other threads:[~2019-07-11 1:33 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-10 3:09 [PATCH v3 0/3] kernel/notifier.c: avoid duplicate registration Xiaoming Ni
2019-07-10 5:49 ` 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 [this message]
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