linux-kernel - Re: [PATCH] clocksource: timer-cadence-ttc: Fix resource leaks in error paths

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Message-ID: <25f4192a-f518-4b26-9757-e23585177dbf@web.de>
Date: Wed, 26 Nov 2025 11:34:33 +0100
From: Markus Elfring <Markus.Elfring@....de>
To: vulab@...as.ac.cn, linux-arm-kernel@...ts.infradead.org
Cc: LKML <linux-kernel@...r.kernel.org>,
 Daniel Lezcano <daniel.lezcano@...aro.org>,
 Michal Simek <michal.simek@....com>, Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] clocksource: timer-cadence-ttc: Fix resource leaks in
 error paths

> The ttc_setup_clocksource() and ttc_setup_clockevent() fail to
> unregister the clock notifier in their error paths, potentially
> leading to a resource leak. Additionally, ttc_setup_clocksource()
> leaks the prepared clock reference upon failure.
…

You may occasionally put more than 65 characters into text lines
of such a change description.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.18-rc7#n658


…
> +++ b/drivers/clocksource/timer-cadence-ttc.c
…
> @@ -377,6 +380,10 @@ static int __init ttc_setup_clocksource(struct clk *clk, void __iomem *base,
>  
>  	err = clocksource_register_hz(&ttccs->cs, ttccs->ttc.freq / PRESCALE);
>  	if (err) {
> +		if (notifier_registered)
> +			clk_notifier_unregister(ttccs->ttc.clk,
> +					&ttccs->ttc.clk_rate_change_nb);
> +		clk_disable_unprepare(ttccs->ttc.clk);
>  		kfree(ttccs);
>  		return err;
>  	}

How do you think about to avoid repeated kfree() calls in such a function implementation?


> @@ -465,13 +472,16 @@ static int __init ttc_setup_clockevent(struct clk *clk,
…
> +out_clk_notifier_unregister:
> +	clk_notifier_unregister(ttcce->ttc.clk,
> +			&ttcce->ttc.clk_rate_change_nb);
…

You may specify this function call in a single line.

Regards,
Markus