Re: [PATCH v9 06/10] usb: dwc3: qcom: Add support to read IRQ's related to multiport

[Johan Hovold <johan@kernel.org>]

On Wed, Jun 21, 2023 at 10:06:24AM +0530, Krishna Kurapati wrote:
> Add support to read Multiport IRQ's related to quad port controller
> of SA8295 Device.
> 
> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> ---
>  drivers/usb/dwc3/dwc3-qcom.c | 108 +++++++++++++++++++++++++++++------
>  1 file changed, 91 insertions(+), 17 deletions(-)

> +static int dwc3_qcom_setup_mp_irq(struct platform_device *pdev)
> +{
> +	struct dwc3_qcom *qcom = platform_get_drvdata(pdev);
> +	char irq_name[15];

The interrupt device-name string can not be allocated on the stack or
reused as it is stored directly in each irqaction structure.

This can otherwise lead to random crashes when accessing
/proc/interrupts:

	https://lore.kernel.org/lkml/ZK6IV_jJPICX5r53@hovoldconsulting.com/

> +	int irq;
> +	int ret;
> +	int i;
> +
> +	for (i = 0; i < 4; i++) {
> +		if (qcom->dp_hs_phy_irq[i])
> +			continue;
> +
> +		sprintf(irq_name, "dp%d_hs_phy_irq", i+1);
> +		irq = dwc3_qcom_get_irq(pdev, irq_name, -1);
> +		if (irq > 0) {
> +			irq_set_status_flags(irq, IRQ_NOAUTOEN);
> +			ret = devm_request_threaded_irq(qcom->dev, irq, NULL,
> +					qcom_dwc3_resume_irq,
> +					IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
> +					irq_name, qcom);
> +			if (ret) {
> +				dev_err(qcom->dev, "%s failed: %d\n", irq_name, ret);
> +				return ret;
> +			}
> +		}
> +
> +		qcom->dp_hs_phy_irq[i] = irq;
> +	}

Johan