Re: [PATCH] mm/filemap: Fix NULL pointer dereference in pagecache_get_page

[Matthew Wilcox <willy@xxxxxxxxxxxxx>]

On Tue, Apr 26, 2022 at 04:25:48PM +0800, Wan Jiabing wrote:
> Fix following coccicheck error:
> mm/folio-compat.c:128:17-21: ERROR: folio is NULL but dereferenced.
>  	folio = __filemap_get_folio(mapping, index, fgp_flags, gfp);
> -	if ((fgp_flags & FGP_HEAD) || !folio || xa_is_value(folio))
> +	if (!folio)
> +		return NULL;
> +	if ((fgp_flags & FGP_HEAD) || xa_is_value(folio))
>  		return &folio->page;

That doesn't dereference the folio.  Coccicheck is wrong.