linux-kernel - Re: Re: [PATCH] rtc: sun6i: Fix memleak in sun6i_rtc_clk

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Date:   Wed, 26 Aug 2020 16:55:14 +0800 (GMT+08:00)
From:   dinghao.liu@....edu.cn
To:     "Chen-Yu Tsai" <wens@...e.org>
Cc:     "Kangjie Lu" <kjlu@....edu>, linux-rtc@...r.kernel.org,
        "Alessandro Zummo" <a.zummo@...ertech.it>,
        "Alexandre Belloni" <alexandre.belloni@...tlin.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        "Maxime Ripard" <mripard@...nel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>
Subject: Re: Re: [PATCH] rtc: sun6i: Fix memleak in sun6i_rtc_clk_init

> On Sun, Aug 23, 2020 at 3:59 PM Dinghao Liu <dinghao.liu@....edu.cn> wrote:
> >
> > When clk_hw_register_fixed_rate_with_accuracy() fails,
> > clk_data should be freed. It's the same for the subsequent
> > error paths.
> 
> I suppose you should also unregister the already registered clocks
> in the latter two error paths?
> 

Sounds reasonable. But I find that the existing kernel code takes different
strategies for this case. of_sama5d4_sckc_setup() uses clk_hw_unregister() 
after clk_hw_register_fixed_rate_with_accuracy(), while _of_fixed_clk_setup()
uses clk_hw_unregister_fixed_rate(). But at91sam926x_pmc_setup() just does
nothing in this case.

Also, tcon_ch1_setup() uses clk_unregister() after clk_register(), while
clk_register_vco_pll() just does nothing. 

So I'm not sure if we should register here and which unregister function to 
use. Would you please give me more specific advice about this problem?

Regards,
Dinghao