From: Marcel Holtmann <marcel@holtmann.org>
To: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: "Gustavo F. Padovan" <gustavo@padovan.org>,
Johan Hedberg <johan.hedberg@gmail.com>,
linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org,
jason.abele@gmail.com
Subject: Re: [PATCH 1/4] Bluetooth: hci_ldisc: fix a race in the hdev closing path
Date: Tue, 30 Aug 2016 09:53:59 -0700 [thread overview]
Message-ID: <3FF88393-A83A-4C5D-B438-E76C923159A5@holtmann.org> (raw)
In-Reply-To: <1471592327-14133-2-git-send-email-boris.brezillon@free-electrons.com>
Hi Boris,
> hci_uart_tty_close() is cancelling any pending write work, but some
> hci_uart_proto implementations might re-schedule this work after its
> cancellation (by calling hci_uart_tx_wakeup()).
>
> Make sure the write work is not re-scheduled in our back while we're
> closing the device.
>
> We also cancel any pending init work and prevent the active one (if
> any) from registering the hdev if the line discipline is being closed.
>
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> ---
> drivers/bluetooth/hci_ldisc.c | 15 ++++++++++++++-
> drivers/bluetooth/hci_uart.h | 1 +
> 2 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
> index dda97398c59a..de7f7f1f995c 100644
> --- a/drivers/bluetooth/hci_ldisc.c
> +++ b/drivers/bluetooth/hci_ldisc.c
> @@ -130,7 +130,9 @@ int hci_uart_tx_wakeup(struct hci_uart *hu)
>
> BT_DBG("");
>
> - schedule_work(&hu->write_work);
> + /* Don't schedule the work if the device is being closed. */
> + if (!test_bit(HCI_UART_CLOSING, &hu->flags))
> + schedule_work(&hu->write_work);
>
> return 0;
> }
> @@ -180,6 +182,11 @@ static void hci_uart_init_work(struct work_struct *work)
> if (!test_and_clear_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
> return;
>
> + if (test_bit(HCI_UART_CLOSING, &hu->flags)) {
> + BT_DBG("HCI device is being closed, don't register it.");
> + return;
> + }
> +
> err = hci_register_dev(hu->hdev);
> if (err < 0) {
> BT_ERR("Can't register HCI device");
> @@ -490,7 +497,13 @@ static void hci_uart_tty_close(struct tty_struct *tty)
> if (hdev)
> hci_uart_close(hdev);
>
> + /*
> + * Set the closing bit to make sure nobody re-schedules the write work
> + * in our back.
> + */
please use the network subsystem comment style here.
Regards
Marcel
next prev parent reply other threads:[~2016-08-30 16:54 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-19 7:38 [PATCH 0/4] Bluetooth: hci_uart: various fixes Boris Brezillon
2016-08-19 7:38 ` [PATCH 1/4] Bluetooth: hci_ldisc: fix a race in the hdev closing path Boris Brezillon
2016-08-30 16:53 ` Marcel Holtmann [this message]
2016-08-30 17:08 ` Boris Brezillon
2016-08-19 7:38 ` [PATCH 2/4] Bluetooth: hci_h5: fix a race in the " Boris Brezillon
2016-08-30 16:54 ` Marcel Holtmann
2016-08-19 7:38 ` [PATCH 3/4] Bluetooth: hci_ldisc: don't release resources in hci_uart_init_work() Boris Brezillon
2016-08-19 7:38 ` [PATCH 4/4] Bluetooth: hci_ldisc: make sure we don't loose HCI_UART_TX_WAKEUP events Boris Brezillon
2016-08-30 16:53 ` Marcel Holtmann
2016-08-30 17:10 ` Boris Brezillon
2016-08-30 13:26 ` [PATCH 0/4] Bluetooth: hci_uart: various fixes Boris Brezillon
2016-08-30 16:48 ` Marcel Holtmann
2016-08-30 17:22 ` Boris Brezillon
2016-08-31 2:08 ` Marcel Holtmann
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3FF88393-A83A-4C5D-B438-E76C923159A5@holtmann.org \
--to=marcel@holtmann.org \
--cc=boris.brezillon@free-electrons.com \
--cc=gustavo@padovan.org \
--cc=jason.abele@gmail.com \
--cc=johan.hedberg@gmail.com \
--cc=linux-bluetooth@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).