Re: [PATCH] xen/debugfs: Check debugfs initialization before using it

From: Greg KH
Date: Mon Dec 09 2013 - 06:16:48 EST


On Mon, Dec 09, 2013 at 06:04:03PM +0800, Ethan Zhao wrote:
> From: "Ethan Zhao" <ethan.kernel@xxxxxxxxx>
>
> Should check debugfs initialization with debugfs_initialized() before using it,
> Because if it isn't initialized, the return value of fake debugfs_create_dir() etc
> functions would be ERR_PTR(-ENODEV), checking with NULL will not work.
>
> V3: Add warning message about debugfs not configured or disabled.
>
> Signed-off-by: Ethan Zhao <ethan.kernel@xxxxxxxxx>
> ---
> arch/x86/xen/debugfs.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/x86/xen/debugfs.c b/arch/x86/xen/debugfs.c
> index c8377fb..033a5dd 100644
> --- a/arch/x86/xen/debugfs.c
> +++ b/arch/x86/xen/debugfs.c
> @@ -9,12 +9,19 @@ static struct dentry *d_xen_debug;
>
> struct dentry * __init xen_init_debugfs(void)
> {
> + if (!debugfs_initialized()) {
> + d_xen_debug = NULL;
> + pr_warning("debugfs is not configured or enabled\n");

No, again, don't say anything, this is useless, just leave the code
as-is, it isn't causing any problems, is it?

gre gk-h
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