Re: [PATCH v2 05/15] usb: typec: tcpm: fix the PD disabled case

From: Alexander Stein <alexander.stein@ew.tq-group.com>
To: Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konrad.dybcio@linaro.org>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Mark Brown <broonie@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Wesley Cheng <quic_wcheng@quicinc.com>,
	Bryan O'Donoghue <bryan.odonoghue@linaro.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Vinod Koul <vkoul@kernel.org>,
	Kishon Vijay Abraham I <kishon@kernel.org>,
	Guenter Roeck <linux@roeck-us.net>,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-usb@vger.kernel.org, linux-phy@lists.infradead.org
Subject: Re: [PATCH v2 05/15] usb: typec: tcpm: fix the PD disabled case
Date: Mon, 15 Jan 2024 10:00:03 +0100	[thread overview]
Message-ID: <12361952.O9o76ZdvQC@steina-w> (raw)
In-Reply-To: <20240113-pmi632-typec-v2-5-182d9aa0a5b3@linaro.org>

Hi Dmitry,

Am Samstag, 13. Januar 2024, 21:55:48 CET schrieb Dmitry Baryshkov:
> If the PD is disabled for the port, port->pds will be left as NULL,
> which causes the following crash during caps intilisation. Fix the
> crash.
> 
> Unable to handle kernel NULL pointer dereference at virtual address
> 0000000000000000 Call trace:
>  tcpm_register_port+0xaec/0xc44
>  qcom_pmic_typec_probe+0x1a4/0x254
>  platform_probe+0x68/0xc0
>  really_probe+0x148/0x2ac
>  __driver_probe_device+0x78/0x12c
>  driver_probe_device+0xd8/0x160
> Bluetooth: hci0: QCA Product ID   :0x0000000a
>  __device_attach_driver+0xb8/0x138
>  bus_for_each_drv+0x80/0xdc
> Bluetooth: hci0: QCA SOC Version  :0x40020150
>  __device_attach+0x9c/0x188
>  device_initial_probe+0x14/0x20
>  bus_probe_device+0xac/0xb0
>  deferred_probe_work_func+0x8c/0xc8
>  process_one_work+0x1ec/0x51c
>  worker_thread+0x1ec/0x3e4
>  kthread+0x120/0x124
>  ret_from_fork+0x10/0x20
> 
> Fixes: cd099cde4ed2 ("usb: typec: tcpm: Support multiple capabilities")
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 5945e3a2b0f7..a0978ed1a257 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -6848,7 +6848,8 @@ struct tcpm_port *tcpm_register_port(struct device
> *dev, struct tcpc_dev *tcpc) if (err)
>  		goto out_role_sw_put;
> 
> -	port->typec_caps.pd = port->pds[0];
> +	if (port->pds)

I'm wondering if the check should be for port->pd_supported instead.
Nevertheless this works on my "pd-disable" platform as well.

Best regards,
Alexander

> +		port->typec_caps.pd = port->pds[0];
> 
>  	port->typec_port = typec_register_port(port->dev, &port-
>typec_caps);
>  	if (IS_ERR(port->typec_port)) {

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