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Date:   Mon, 3 May 2021 13:22:55 +0200
From:   Johan Hovold <johan@kernel.org>
To:     Pavel Skripkin <paskripkin@gmail.com>
Cc:     marcel@holtmann.org, johan.hedberg@gmail.com,
        linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org, Rocky Liao <rjliao@codeaurora.org>
Subject: Re: [PATCH v2] bluetooth: hci_qca: fix potential GPF
Message-ID: <YI/dDxosAwxtySqx@hovoldconsulting.com>
References: <YI+s2Hms/56Pvatu@hovoldconsulting.com>
 <20210503100605.5223-1-paskripkin@gmail.com>
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On Mon, May 03, 2021 at 01:06:05PM +0300, Pavel Skripkin wrote:
> In qca_power_shutdown() qcadev local variable is
> initialized by hu->serdev.dev private data, but
> hu->serdev can be NULL and there is a check for it.
> 
> Since, qcadev is not used before
> 
> 	if (!hu->serdev)
> 		return;
> 
> we can move its initialization after this "if" to
> prevent GPF.
> 
> Fixes: 5559904ccc08 ("Bluetooth: hci_qca: Add QCA Rome power off support to the qca_power_shutdown()")
> Cc: stable@vger.kernel.org # v5.6+
> Cc: Rocky Liao <rjliao@codeaurora.org>
> Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
> ---

Next time, put a changelog here so we know what changed since earlier
version(s).

Reviewed-by: Johan Hovold <johan@kernel.org>

>  drivers/bluetooth/hci_qca.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index de36af63e182..9589ef6c0c26 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -1820,8 +1820,6 @@ static void qca_power_shutdown(struct hci_uart *hu)
>  	unsigned long flags;
>  	enum qca_btsoc_type soc_type = qca_soc_type(hu);
>  
> -	qcadev = serdev_device_get_drvdata(hu->serdev);
> -
>  	/* From this point we go into power off state. But serial port is
>  	 * still open, stop queueing the IBS data and flush all the buffered
>  	 * data in skb's.
> @@ -1837,6 +1835,8 @@ static void qca_power_shutdown(struct hci_uart *hu)
>  	if (!hu->serdev)
>  		return;
>  
> +	qcadev = serdev_device_get_drvdata(hu->serdev);
> +
>  	if (qca_is_wcn399x(soc_type)) {
>  		host_set_baudrate(hu, 2400);
>  		qca_send_power_pulse(hu, false);