linux-kernel - Re: [PATCH] clk: boston: fix memory leak of 'onecell' on error return paths

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Message-ID: <20180509140135.4dndt3baomtxups5@mwanda>
Date:   Wed, 9 May 2018 17:01:35 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Colin King <colin.king@...onical.com>
Cc:     Paul Burton <paul.burton@...s.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-mips@...ux-mips.org,
        linux-clk@...r.kernel.org, kernel-janitors@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] clk: boston: fix memory leak of 'onecell' on error
 return paths

On Wed, May 09, 2018 at 02:40:31PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> There are several error return paths that don't free up onecell
> and hence we have some memory leaks. Add an error exit path that
> kfree's onecell to fix the leaks.
> 
> Signed-off-by: Colin Ian King <colin.king@...onical.com>
> ---
>  drivers/clk/imgtec/clk-boston.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/clk/imgtec/clk-boston.c b/drivers/clk/imgtec/clk-boston.c
> index 15af423cc0c9..d6bc468ff551 100644
> --- a/drivers/clk/imgtec/clk-boston.c
> +++ b/drivers/clk/imgtec/clk-boston.c
> @@ -73,27 +73,34 @@ static void __init clk_boston_setup(struct device_node *np)
>  	hw = clk_hw_register_fixed_rate(NULL, "input", NULL, 0, in_freq);
>  	if (IS_ERR(hw)) {
>  		pr_err("failed to register input clock: %ld\n", PTR_ERR(hw));
> -		return;
> +		goto error;

I hate vague label names like "error" and "out"...

There are a bunch of other resources that we should free if we decide
it's worth freeing things.  Can this even boot without the clk?  When
the label names says what is freed, then you mentally only have to keep
track of the most recently allocated resource.  So if

	hw = clk_hw_register_fixed_rate(NULL, "input", NULL, 0, in_freq);

succeeds then the next goto is going to "goto free_clk_input;".

regards,
dan carpenter