[PATCH-next] fs/cifs: Fix resource leak

[Dan Carpenter]

On Tue, May 04, 2021 at 01:43:43PM +0100, Khaled ROMDHANI wrote:
> The -EIO error return path is leaking memory allocated
> to page. Fix this by invoking the free_dentry_path before
> the return.
> 
> Addresses-Coverity: ("Resource leak")
> Signed-off-by: Khaled ROMDHANI <khaledromdhani216 at gmail.com>

Add a Fixes tag.

Fixes: 583248493f78 ("cifs: add shutdown support")

> ---
>  fs/cifs/link.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/cifs/link.c b/fs/cifs/link.c
> index 1cbe7ec73728..1485c6095ba1 100644
> --- a/fs/cifs/link.c
> +++ b/fs/cifs/link.c
> @@ -686,8 +686,10 @@ cifs_symlink(struct user_namespace *mnt_userns, struct inode *inode,
>  	void *page = alloc_dentry_path();
>  	struct inode *newinode = NULL;
>  
> -	if (unlikely(cifs_forced_shutdown(cifs_sb)))
> +	if (unlikely(cifs_forced_shutdown(cifs_sb))) {
> +		free_dentry_path(page);
>  		return -EIO;
> +	}

Better to move the allocation here.  Avoid calling functions which can
fail in the declaration block.  Better to test for NULL directly instead
of hiding the test inside the build_path_from_dentry() function.

	page = alloc_dentry_path();
	if (!page)
		return -ENOMEM;

The error handling in this function is slightly unweildy...

regards,
dan carpenter