Re: [PATCH] serial: ucc_uart: Use platform IRQ helper

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] probe deferral: leak of async firmware load due to platform_get_irq() ordering
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commit 887c64b890c9273da1e7e1715e89bca754adbfb0
Author: Rosen Penev <rosenp@gmail.com>

serial: ucc_uart: Use platform IRQ helper

This commit updates the driver to use platform_get_irq() instead of
irq_of_parse_and_map() to obtain the IRQ. The IRQ lookup is moved earlier
in the probe function to simplify error handling and explicitly handle
probe deferral.

> diff --git a/drivers/tty/serial/ucc_uart.c b/drivers/tty/serial/ucc_uart.c
> index 6b7dcbbacd13d..c3c83a59dcce7 100644
> --- a/drivers/tty/serial/ucc_uart.c
> +++ b/drivers/tty/serial/ucc_uart.c
> @@ -1238,6 +1238,7 @@ static int ucc_uart_probe(struct platform_device *ofdev)
>  	struct uart_qe_port *qe_port = NULL;
>  	struct resource res;
>  	u32 val;
> +	int irq;
>  	int ret;
>  
>  	/*
> @@ -1247,6 +1248,10 @@ static int ucc_uart_probe(struct platform_device *ofdev)
>  	if (ret)
>  		return ret;
>  
> +	irq = platform_get_irq(ofdev, 0);
> +	if (irq < 0)
> +		return irq;
> +

[Severity: High]
If platform_get_irq() returns -EPROBE_DEFER here, does this leak the
asynchronous firmware load initiated by the preceding call to
soft_uart_init()?

Looking at soft_uart_init(), an async load is triggered like this:

    ret = request_firmware_nowait(THIS_MODULE,
                                  FW_ACTION_UEVENT, filename, &ofdev->dev,
                                  GFP_KERNEL, &ofdev->dev, uart_firmware_cont);

Since the async firmware load is not cancelled on probe deferral, the probe 
will eventually be retried and will call soft_uart_init() a second time. 

Could this lead to duplicated asynchronous firmware loads and concurrent
execution of qe_upload_firmware() upon probe retry, potentially causing
data races or hardware state corruption?

Would it make sense to move platform_get_irq() even earlier in the
probe function, before soft_uart_init(), to prevent this probe deferral
side effect?

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/20260925182504.54976-1-rosenp@gmail.com?part=1