Re: [PATCH v2 1/3] rtc: ftrtc010: fix clock resource leak on probe failure

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Shared interrupt handler unconditionally returns IRQ_HANDLED, defeating the kernel's spurious interrupt detection.
--

commit 8daf0ea14af5dc0abeba82e55b73ddd78a69f258
Author: Liu Dalin <liudalin@kylinsec.com.cn>

rtc: ftrtc010: fix clock resource leak on probe failure

This commit fixes a clock resource leak during the RTC probe failure path.
It ensures that if devm_rtc_register_device() fails, the driver properly
jumps to the error handling path to release extclk and pclk resources.

> diff --git a/drivers/rtc/rtc-ftrtc010.c b/drivers/rtc/rtc-ftrtc010.c
> index 02608d3784958..f398d6dc85ae4 100644
> --- a/drivers/rtc/rtc-ftrtc010.c
> +++ b/drivers/rtc/rtc-ftrtc010.c
> @@ -181,7 +181,11 @@ static int ftrtc010_rtc_probe(struct platform_device *pdev)
>  	if (unlikely(ret))
>  		goto err_disable_extclk;
>  

[Severity: High]
This isn't a bug introduced by this patch, but a pre-existing issue. The
handler is registered with the IRQF_SHARED flag just above this check:

	ret = devm_request_irq(dev, rtc->rtc_irq, ftrtc010_rtc_interrupt,
			       IRQF_SHARED, pdev->name, dev);

However, the interrupt handler unconditionally returns IRQ_HANDLED without
verifying the hardware status:

static irqreturn_t ftrtc010_rtc_interrupt(int irq, void *dev)
{
	return IRQ_HANDLED;
}

Can this cause a system lockup if an unhandled interrupt storm occurs on
the shared IRQ line? 

If another device shares this line or if the bootloader leaves the RTC 
interrupt enabled, the kernel might fail to disable the spurious interrupt 
because this handler falsely claims it, starving the CPU.

> -	return devm_rtc_register_device(rtc_dev);
> +	ret = devm_rtc_register_device(rtc_dev);
> +	if (ret)
> +		goto err_disable_extclk;
> +
> +	return 0;
>  
>  err_disable_extclk:
>  	clk_disable_unprepare(rtc->extclk);

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260827080320.3351155-1-liudalin@kylinsec.com.cn?part=1