From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: "linux-bluetooth@vger.kernel.org"
<linux-bluetooth@vger.kernel.org>, LinMa <linma@zju.edu.cn>
Subject: Re: [RFC] Bluetooth: hci_sock: Fix calling lock_sock when handling HCI_DEV_UNREG
Date: Sun, 18 Jul 2021 15:22:03 +0900 [thread overview]
Message-ID: <166a8c6d-9928-4edf-8082-111e555f5808@i-love.sakura.ne.jp> (raw)
In-Reply-To: <CABBYNZLdYXHxD47xO+TX6U=MK1RtvuAAHLYvS1vTsuk4nFQfrg@mail.gmail.com>
On 2021/07/18 14:16, Luiz Augusto von Dentz wrote:
> Anyway after all these discussion Im even
> more convinced that the real problem lies in hci_dev_get/hold, after
> all references are usually used to prevent the objects to be freed but
> in this case it doesn't and no locking will gonna fix that.
If hci_dev_hold() calls atomic_long_add_unless(&file->f_count, 1, 0) under RCU,
vhci_release(file) would not be called until all sockets using that hdev drops
the reference, and hci_sock_dev_event(hdev, HCI_DEV_UNREG) no longer needs to
traverse sockets on hci_sk_list.head list. This requires adding "struct file *" to
"struct hci_dev". My patch keeps changes be confined to only hci_sock_dev_event().
next prev parent reply other threads:[~2021-07-18 6:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-17 0:07 [RFC] Bluetooth: hci_sock: Fix calling lock_sock when handling HCI_DEV_UNREG Luiz Augusto von Dentz
2021-07-17 2:04 ` bluez.test.bot
2021-07-18 2:22 ` Tetsuo Handa
2021-07-18 5:16 ` Luiz Augusto von Dentz
2021-07-18 6:22 ` Tetsuo Handa [this message]
2021-07-18 6:51 ` Luiz Augusto von Dentz
2021-07-18 14:56 ` Tetsuo Handa
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