linux-kernel - Re: [RFC][PATCH v2 08/31] timers: Bluetooth: Use del_timer

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Date:   Fri, 28 Oct 2022 17:12:44 -0700
From:   Luiz Augusto von Dentz <luiz.dentz@...il.com>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     linux-kernel@...r.kernel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Stephen Boyd <sboyd@...nel.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Marcel Holtmann <marcel@...tmann.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        linux-bluetooth@...r.kernel.org
Subject: Re: [RFC][PATCH v2 08/31] timers: Bluetooth: Use del_timer_shutdown()
 before freeing timer

Hi Steven,

On Thu, Oct 27, 2022 at 8:09 AM Steven Rostedt <rostedt@...dmis.org> wrote:
>
> From: "Steven Rostedt (Google)" <rostedt@...dmis.org>
>
> Before a timer is freed, del_timer_shutdown() must be called.
>
> Link: https://lore.kernel.org/all/20220407161745.7d6754b3@gandalf.local.home/
>
> Cc: Marcel Holtmann <marcel@...tmann.org>
> Cc: Johan Hedberg <johan.hedberg@...il.com>
> Cc: Luiz Augusto von Dentz <luiz.dentz@...il.com>
> Cc: linux-bluetooth@...r.kernel.org
> Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>

Acked-by: Luiz Augusto von Dentz <luiz.von.dentz@...el.com>

Btw, we do seem to have similar problems with the likes of
cancel_delayed_work/cancel_delayed_work_sync so wonder if it wouldn't
be the case to introduce something like shutdown_delayed_work before
freeing the struct/object containing it?

> ---
>  drivers/bluetooth/hci_bcsp.c | 2 +-
>  drivers/bluetooth/hci_h5.c   | 2 +-
>  drivers/bluetooth/hci_qca.c  | 4 ++--
>  3 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/bluetooth/hci_bcsp.c b/drivers/bluetooth/hci_bcsp.c
> index cf4a56095817..69caaff37141 100644
> --- a/drivers/bluetooth/hci_bcsp.c
> +++ b/drivers/bluetooth/hci_bcsp.c
> @@ -737,7 +737,7 @@ static int bcsp_close(struct hci_uart *hu)
>  {
>         struct bcsp_struct *bcsp = hu->priv;
>
> -       del_timer_sync(&bcsp->tbcsp);
> +       del_timer_shutdown(&bcsp->tbcsp);
>
>         hu->priv = NULL;
>
> diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c
> index c5a0409ef84f..08a36ea9eea9 100644
> --- a/drivers/bluetooth/hci_h5.c
> +++ b/drivers/bluetooth/hci_h5.c
> @@ -253,7 +253,7 @@ static int h5_close(struct hci_uart *hu)
>  {
>         struct h5 *h5 = hu->priv;
>
> -       del_timer_sync(&h5->timer);
> +       del_timer_shutdown(&h5->timer);
>
>         skb_queue_purge(&h5->unack);
>         skb_queue_purge(&h5->rel);
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index 8df11016fd51..1796166ba35d 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -697,8 +697,8 @@ static int qca_close(struct hci_uart *hu)
>         skb_queue_purge(&qca->txq);
>         skb_queue_purge(&qca->rx_memdump_q);
>         destroy_workqueue(qca->workqueue);
> -       del_timer_sync(&qca->tx_idle_timer);
> -       del_timer_sync(&qca->wake_retrans_timer);
> +       del_timer_shutdown(&qca->tx_idle_timer);
> +       del_timer_shutdown(&qca->wake_retrans_timer);
>         qca->hu = NULL;
>
>         kfree_skb(qca->rx_skb);
> --
> 2.35.1



-- 
Luiz Augusto von Dentz