Re: [PATCH] rtc: meson: fix refcount leak in meson_rtc_get_bus

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Bogus fix attempting to fix a non-existent refcount leak, which violates the reset API contract and introduces a potential counter underflow.
--

commit dec7a1c708a5b28d1344bf6fb038df54d6001df3
Author: WenTao Liang <vulab@iscas.ac.cn>
rtc: meson: fix refcount leak in meson_rtc_get_bus

This commit adds calls to reset_control_rearm() in both the error and success
paths of meson_rtc_get_bus() after triggering a reset. The intention is to
prevent a triggered_count leak on shared reset controls.

> diff --git a/drivers/rtc/rtc-meson.c b/drivers/rtc/rtc-meson.c
> index 21eceb9e2e134..3c45cd761a15a 100644
> --- a/drivers/rtc/rtc-meson.c
> +++ b/drivers/rtc/rtc-meson.c
> @@ -146,8 +146,12 @@ static int meson_rtc_get_bus(struct meson_rtc *rtc)
>  		dev_warn(rtc->dev, "failed to get bus, resetting RTC\n");
>  
>  		ret = reset_control_reset(rtc->reset);
> -		if (ret)
> +		if (ret) {
> +			reset_control_rearm(rtc->reset);

[Severity: Medium]
Is this fix applicable to this driver's reset control?

The reset control rtc->reset is acquired as an exclusive control using
devm_reset_control_get(). Exclusive controls do not track triggered_count,
so calling reset_control_rearm() is a no-op in this context, meaning there
was no leak to fix.

Additionally, if this were a shared reset control, would calling
reset_control_rearm() on the error path cause a counter underflow?

The reset core already handles the rollback internally by decrementing
triggered_count if the underlying reset fails. Adding a manual
reset_control_rearm() here on failure would decrement it a second time,
which could trigger a WARN_ON() for dropping below zero.

> +			return ret;
> +		}
> +
> +		reset_control_rearm(rtc->reset);
>  	}
>  
>  	dev_err(rtc->dev, "bus is not ready\n");

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260611034040.59682-1-vulab@iscas.ac.cn?part=1

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