linux-kernel - Re: [Patch] hdac_sysfs: Fix a memory leaking bug in sound/hda/hdac

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Message-ID: <s5hzhnmn5qw.wl-tiwai@suse.de>
Date:   Thu, 16 May 2019 10:49:43 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     "Gen Zhang" <blackgod016574@...il.com>
Cc:     <perex@...ex.cz>, <linux-kernel@...r.kernel.org>
Subject: Re: [Patch] hdac_sysfs: Fix a memory leaking bug in sound/hda/hdac_sysfs.c file of Linux 5.1

On Thu, 16 May 2019 10:40:03 +0200,
Gen Zhang wrote:
> 
> tree->root and tree->nodes are allocated by memory allocation 
> functions. And tree is also an allocated memory. When allocation of 
> tree->root and tree->nodes fails, not freeing tree will leak memory. 
> Thus we should free tree in this situation.

No, the leftover is freed in the caller side by calling
widget_tree_free().


thanks,

Takashi

> 
> Signed-off-by: Gen Zhang <blackgod016574@...il.com>
> 
> ---
> diff --git a/sound/hda/hdac_sysfs.c b/sound/hda/hdac_sysfs.c
> index fb2aa34..5d8a939 100644
> --- a/sound/hda/hdac_sysfs.c
> +++ b/sound/hda/hdac_sysfs.c
> @@ -370,12 +370,12 @@ static int widget_tree_create(struct hdac_device *codec)
>  
>  	tree->root = kobject_create_and_add("widgets", &codec->dev.kobj);
>  	if (!tree->root)
> -		return -ENOMEM;
> +		goto free_tree;
>  
>  	tree->nodes = kcalloc(codec->num_nodes + 1, sizeof(*tree->nodes),
>  			      GFP_KERNEL);
>  	if (!tree->nodes)
> -		return -ENOMEM;
> +		goto free_tree;
>  
>  	for (i = 0, nid = codec->start_nid; i < codec->num_nodes; i++, nid++) {
>  		err = add_widget_node(tree->root, nid, &widget_node_group,
> @@ -393,6 +393,9 @@ static int widget_tree_create(struct hdac_device *codec)
>  
>  	kobject_uevent(tree->root, KOBJ_CHANGE);
>  	return 0;
> +free_tree:
> +	kfree(tree);
> +	return -ENOMEM;
>  }
>  
>  int hda_widget_sysfs_init(struct hdac_device *codec)
> ---
>