linux-kernel - Re: [PATCH 5.4 34/47] rtc: sun6i: Fix memleak in sun6i_rtc_clk

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Date:   Wed, 6 Jan 2021 14:07:45 +0100
From:   Pavel Machek <pavel@...x.de>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Dinghao Liu <dinghao.liu@....edu.cn>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Sasha Levin <sashal@...nel.org>
Subject: Re: [PATCH 5.4 34/47] rtc: sun6i: Fix memleak in sun6i_rtc_clk_init

Hi!

> From: Dinghao Liu <dinghao.liu@....edu.cn>
> 
> [ Upstream commit 28d211919e422f58c1e6c900e5810eee4f1ce4c8 ]
> 
> When clk_hw_register_fixed_rate_with_accuracy() fails,
> clk_data should be freed. It's the same for the subsequent
> two error paths, but we should also unregister the already
> registered clocks in them.

This still leaks rtc, AFAICT. What is worse, sun6i_rtc will point to
invalid memory after the error exit.

Something like this?

Best regards,
								Pavel

diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c
index e85abe805606..59389bb99e39 100644
--- a/drivers/rtc/rtc-sun6i.c
+++ b/drivers/rtc/rtc-sun6i.c
@@ -211,6 +211,7 @@ static void __init sun6i_rtc_clk_init(struct device_node *node)
 	rtc->base = of_io_request_and_map(node, 0, of_node_full_name(node));
 	if (IS_ERR(rtc->base)) {
 		pr_crit("Can't map RTC registers");
+		kfree(rtc);
 		goto err;
 	}
 
@@ -272,6 +273,8 @@ static void __init sun6i_rtc_clk_init(struct device_node *node)
 	clk_hw_unregister_fixed_rate(rtc->int_osc);
 err:
 	kfree(clk_data);
+	kfree(rtc);
+	sun6i_rtc = NULL;
 }
 CLK_OF_DECLARE_DRIVER(sun6i_rtc_clk, "allwinner,sun6i-a31-rtc",
 		      sun6i_rtc_clk_init);

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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