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From:   Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Subject: Re: [PATCH v3] Bluetooth: call lock_sock() outside of spinlock
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To:     LinMa <3160105373@zju.edu.cn>
Cc:     Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>,
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Date:   Thu, 22 Jul 2021 18:36:58 +0900
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On 2021/07/17 0:26, LinMa wrote:
> Hello everyone,
> 
> Sorry, it's my fault to cause the misunderstanding.
> 
> As I keep mentioning "hci_sock_sendmsg()" instead of "hci_sock_bound_ioctl()". In fact,
> both these two functions are able to cause the race.

I sent two patches for avoiding page fault with kernel lock held.

  [PATCH v2] Bluetooth: reorganize ioctls from hci_sock_bound_ioctl()
  https://lkml.kernel.org/r/39b677ce-dcbf-6393-6279-88ed3a9e570e@i-love.sakura.ne.jp

  [PATCH] Bluetooth: reorganize functions from hci_sock_sendmsg()
  https://lkml.kernel.org/r/20210722074208.8040-1-penguin-kernel@I-love.SAKURA.ne.jp

These two patches will eliminate user-controlled delay at lock_sock() which

  [PATCH v3] Bluetooth: call lock_sock() outside of spinlock section
  https://lkml.kernel.org/r/48d66166-4d39-4fe2-3392-7e0c84b9bdb3@i-love.sakura.ne.jp

would suffer.

Are you aware of more locations which trigger page fault with sock lock held?
If none, we can send these three patches together.

If we are absolutely sure that there is no more locations, we could try choice (1) or (2)
at https://lkml.kernel.org/r/05535d35-30d6-28b6-067e-272d01679d24@i-love.sakura.ne.jp .