linux-kernel - Re: [PATCH] pstore: no need to check return value of debugfs

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Message-ID: <201906201115.37C12233AB@keescook>
Date:   Thu, 20 Jun 2019 11:16:04 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Anton Vorontsov <anton@...msg.org>,
        Colin Cross <ccross@...roid.com>,
        Tony Luck <tony.luck@...el.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] pstore: no need to check return value of debugfs_create
 functions

On Wed, Jun 12, 2019 at 05:20:33PM +0200, Greg Kroah-Hartman wrote:
> When calling debugfs functions, there is no need to ever check the
> return value.  The function can work or not, but the code logic should
> never do something different based on this.
> 
> Cc: Kees Cook <keescook@...omium.org>
> Cc: Anton Vorontsov <anton@...msg.org>
> Cc: Colin Cross <ccross@...roid.com>
> Cc: Tony Luck <tony.luck@...el.com>
> Cc: linux-kernel@...r.kernel.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

Thanks; applied to my for-next/pstore tree.

-Kees

> ---
>  fs/pstore/ftrace.c | 18 ++----------------
>  1 file changed, 2 insertions(+), 16 deletions(-)
> 
> diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c
> index b8a0931568f8..fd9468928bef 100644
> --- a/fs/pstore/ftrace.c
> +++ b/fs/pstore/ftrace.c
> @@ -120,27 +120,13 @@ static struct dentry *pstore_ftrace_dir;
>  
>  void pstore_register_ftrace(void)
>  {
> -	struct dentry *file;
> -
>  	if (!psinfo->write)
>  		return;
>  
>  	pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
> -	if (!pstore_ftrace_dir) {
> -		pr_err("%s: unable to create pstore directory\n", __func__);
> -		return;
> -	}
> -
> -	file = debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir,
> -				   NULL, &pstore_knob_fops);
> -	if (!file) {
> -		pr_err("%s: unable to create record_ftrace file\n", __func__);
> -		goto err_file;
> -	}
>  
> -	return;
> -err_file:
> -	debugfs_remove(pstore_ftrace_dir);
> +	debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir, NULL,
> +			    &pstore_knob_fops);
>  }
>  
>  void pstore_unregister_ftrace(void)
> -- 
> 2.22.0
> 

-- 
Kees Cook