linux-kernel - Re: [PATCH] Bluetooth: hci_qca: Fix "Sleep inside atomic section" warning

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Date:   Wed, 30 May 2018 08:13:35 +0200
From:   Marcel Holtmann <marcel@...tmann.org>
To:     Thierry Escande <thierry.escande@...aro.org>
Cc:     Johan Hedberg <johan.hedberg@...il.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        BlueZ development <linux-bluetooth@...r.kernel.org>,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Bluetooth: hci_qca: Fix "Sleep inside atomic section"
 warning

Hi Thierry,

> This patch fixes the following warning during boot:
> 
> do not call blocking ops when !TASK_RUNNING; state=1 set at
> [<(ptrval)>] qca_setup+0x194/0x750 [hci_uart]
> WARNING: CPU: 2 PID: 1878 at kernel/sched/core.c:6135
> __might_sleep+0x7c/0x88
> 
> In qca_set_baudrate(), the current task state is set to
> TASK_UNINTERRUPTIBLE before going to sleep for 300ms. It was then
> restored to TASK_INTERRUPTIBLE. This patch sets the current task state
> back to TASK_RUNNING instead.
> 
> Signed-off-by: Thierry Escande <thierry.escande@...aro.org>
> ---
> drivers/bluetooth/hci_qca.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

patch has been applied to bluetooth-next tree.

> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index f05382b5a65d..51790dd02afb 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -910,7 +910,7 @@ static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
> 	 */
> 	set_current_state(TASK_UNINTERRUPTIBLE);
> 	schedule_timeout(msecs_to_jiffies(BAUDRATE_SETTLE_TIMEOUT_MS));
> -	set_current_state(TASK_INTERRUPTIBLE);
> +	set_current_state(TASK_RUNNING);
> 

However wouldn’t it better to use msleep or similar instead of open coding it with schedule_timeout?

Regards

Marcel