[PATCH v1] lib:Fix an NULL vs IS_ERR() bug for debugfs_create_dir() in err_inject_init()

[PATCH v1] lib:Fix an NULL vs IS_ERR() bug for debugfs_create_dir() in err_inject_init()

[Wang Ming]

The debugfs_create_dir() function returns error pointers.
It never returns NULL. Most incorrect error checks were fixed,
but the one in err_inject_init() was forgotten.

Fix the remaining error check.

Signed-off-by: Wang Ming <machel@vivo.com>
---
 lib/notifier-error-inject.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/notifier-error-inject.c b/lib/notifier-error-inject.c
index 2b24ea6c9497..c49354c23802 100644
--- a/lib/notifier-error-inject.c
+++ b/lib/notifier-error-inject.c
@@ -83,7 +83,7 @@ static int __init err_inject_init(void)
 	notifier_err_inject_dir =
 		debugfs_create_dir("notifier-error-inject", NULL);
 
-	if (!notifier_err_inject_dir)
+	if (IS_ERR(notifier_err_inject_dir))
 		return -ENOMEM;
 
 	return 0;
-- 
2.25.1

Re: [PATCH v1] lib:Fix an NULL vs IS_ERR() bug for debugfs_create_dir() in err_inject_init()

[Greg Kroah-Hartman]

On Wed, Jul 12, 2023 at 09:52:11PM +0800, Wang Ming wrote:
> The debugfs_create_dir() function returns error pointers.
> It never returns NULL. Most incorrect error checks were fixed,
> but the one in err_inject_init() was forgotten.
> 
> Fix the remaining error check.
> 
> Signed-off-by: Wang Ming <machel@vivo.com>
> ---
>  lib/notifier-error-inject.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/notifier-error-inject.c b/lib/notifier-error-inject.c
> index 2b24ea6c9497..c49354c23802 100644
> --- a/lib/notifier-error-inject.c
> +++ b/lib/notifier-error-inject.c
> @@ -83,7 +83,7 @@ static int __init err_inject_init(void)
>  	notifier_err_inject_dir =
>  		debugfs_create_dir("notifier-error-inject", NULL);
>  
> -	if (!notifier_err_inject_dir)
> +	if (IS_ERR(notifier_err_inject_dir))
>  		return -ENOMEM;

Please do not do any different codepath if a debugfs_*() call fails or
succeeds.

Why do you need to check this at all?

And why are you creating this directory at the root of debugfs?

thanks,

greg k-h

Re: 回复: [PATCH v1] lib:Fix an NULL vs IS_ERR() bug for debugfs_create_dir() in err_inject_init()

[Greg Kroah-Hartman]

A: http://en.wikipedia.org/wiki/Top_post
Q: Were do I find info about this thing called top-posting?
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

A: No.
Q: Should I include quotations after my reply?

http://daringfireball.net/2007/07/on_top

On Thu, Jul 13, 2023 at 02:09:03AM +0000, 王明-软件底层技术部 wrote:
> Hi greg k-h
> I proposed this patch because I found that debugfs_create_dir() does
> not return NULL, but returns an error pointer, executing if statements
> according to the original code meaning no error, so I made this change
> : )

That's fine, but you should fix this up to use the api properly if you
are making these types of changes, otherwise we just have to do it again
in the future.

thanks,

greg k-h