linux-kernel - Re: memory leak and other oddness in pinctrl-mvebu.c

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Date:	Sat, 9 Mar 2013 17:53:33 -0500
From:	Jason Cooper <jason@...edaemon.net>
To:	David Woodhouse <dwmw2@...radead.org>
Cc:	Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	Stephen Warren <swarren@...dotorg.org>,
	linux-kernel@...r.kernel.org
Subject: Re: memory leak and other oddness in pinctrl-mvebu.c

On Sat, Mar 09, 2013 at 07:02:05PM +0000, David Woodhouse wrote:
> On Sat, 2013-03-09 at 09:49 +0100, Sebastian Hesselbarth wrote:
> > I don't have a strong opinion on that, but I prefer not to have the list
> > statically in the SoC specific drivers. I think counting the number of
> > unique functions for each SoC specific driver once and verify the above
> > heuristic (fewer unique functions than pins) is still valid. Then drop
> > the krealloc and leave the array the way it is allocated on devm_kzalloc.
> 
> Yeah. If you stick a check in the loop and make it warn if it *would*
> have run over the end of the array, that sounds like it ought to be
> fine. Something like this, perhaps? Still untested but otherwise
> Signed-off-by: David Woodhouse <David.Woodhouse@...el.com>
> 
> diff --git a/drivers/pinctrl/mvebu/pinctrl-mvebu.c b/drivers/pinctrl/mvebu/pinctrl-mvebu.c
> index c689c04..55d55d5 100644
> --- a/drivers/pinctrl/mvebu/pinctrl-mvebu.c
> +++ b/drivers/pinctrl/mvebu/pinctrl-mvebu.c
> @@ -478,7 +478,8 @@ static struct pinctrl_ops mvebu_pinctrl_ops = {
>  	.dt_free_map = mvebu_pinctrl_dt_free_map,
>  };
>  
> -static int _add_function(struct mvebu_pinctrl_function *funcs, const char *name)
> +static int _add_function(struct mvebu_pinctrl_function *funcs, int nr_funcs,
> +			 const char *name)
>  {
>  	while (funcs->num_groups) {
>  		/* function already there */
> @@ -487,7 +488,11 @@ static int _add_function(struct mvebu_pinctrl_function *funcs, const char *name)
>  			return -EEXIST;
>  		}
>  		funcs++;
> +		nr_funcs--;
>  	}
> +	if (!nr_funcs)

shouldn't this be:

	if (nr_funcs <= 0)

thx,

Jason.

> +		return -EOVERFLOW;
> +
>  	funcs->name = name;
>  	funcs->num_groups = 1;
>  	return 0;
> @@ -501,7 +506,7 @@ static int mvebu_pinctrl_build_functions(struct platform_device *pdev,
>  	int n, s;
>  
>  	/* we allocate functions for number of pins and hope
> -	 * there are less unique functions than pins available */
> +	 * there are fewer unique functions than pins available */
>  	funcs = devm_kzalloc(&pdev->dev, pctl->desc.npins *
>  			     sizeof(struct mvebu_pinctrl_function), GFP_KERNEL);
>  	if (!funcs)
> @@ -510,26 +515,27 @@ static int mvebu_pinctrl_build_functions(struct platform_device *pdev,
>  	for (n = 0; n < pctl->num_groups; n++) {
>  		struct mvebu_pinctrl_group *grp = &pctl->groups[n];
>  		for (s = 0; s < grp->num_settings; s++) {
> +			int ret;
> +
>  			/* skip unsupported settings on this variant */
>  			if (pctl->variant &&
>  			    !(pctl->variant & grp->settings[s].variant))
>  				continue;
>  
>  			/* check for unique functions and count groups */
> -			if (_add_function(funcs, grp->settings[s].name))
> +			ret = _add_function(funcs, pctl->desc.npins,
> +					    grp->settings[s].name);
> +			if (ret == -EOVERFLOW)
> +				dev_err(&pdev->dev,
> +					"More functions than pins(%d)\n",
> +					pctl->desc.npins);
> +			if (ret)
>  				continue;
>  
>  			num++;
>  		}
>  	}
>  
> -	/* with the number of unique functions and it's groups known,
> -	   reallocate functions and assign group names */
> -	funcs = krealloc(funcs, num * sizeof(struct mvebu_pinctrl_function),
> -			 GFP_KERNEL);
> -	if (!funcs)
> -		return -ENOMEM;
> -
>  	pctl->num_functions = num;
>  	pctl->functions = funcs;
>  
> 
> 
> -- 
> dwmw2
> 


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