module/decompress: Avoid open-coded kvrealloc()

[PATCH] module/decompress: Avoid open-coded kvrealloc()

Posted by Kees Cook 1 week, 5 days ago

Replace open-coded allocate/copy with kvrealloc().

Signed-off-by: Kees Cook <kees@kernel.org>
---
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: <linux-modules@vger.kernel.org>
---
 kernel/module/decompress.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/module/decompress.c b/kernel/module/decompress.c
index 474e68f0f063..36f52a232a12 100644
--- a/kernel/module/decompress.c
+++ b/kernel/module/decompress.c
@@ -17,16 +17,16 @@
 static int module_extend_max_pages(struct load_info *info, unsigned int extent)
 {
 	struct page **new_pages;
+	unsigned int new_max = info->max_pages + extent;
 
-	new_pages = kvmalloc_array(info->max_pages + extent,
-				   sizeof(info->pages), GFP_KERNEL);
+	new_pages = kvrealloc(info->pages,
+			      size_mul(new_max, sizeof(*info->pages)),
+			      GFP_KERNEL);
 	if (!new_pages)
 		return -ENOMEM;
 
-	memcpy(new_pages, info->pages, info->max_pages * sizeof(info->pages));
-	kvfree(info->pages);
 	info->pages = new_pages;
-	info->max_pages += extent;
+	info->max_pages = new_max;
 
 	return 0;
 }
-- 
2.34.1

Re: [PATCH] module/decompress: Avoid open-coded kvrealloc()

Posted by Petr Pavlu 1 week, 4 days ago

On 11/19/25 11:54 PM, Kees Cook wrote:
> Replace open-coded allocate/copy with kvrealloc().
> 
> Signed-off-by: Kees Cook <kees@kernel.org>
> ---
> Cc: Petr Pavlu <petr.pavlu@suse.com>
> Cc: Luis Chamberlain <mcgrof@kernel.org>
> Cc: Sami Tolvanen <samitolvanen@google.com>
> Cc: Daniel Gomez <da.gomez@samsung.com>
> Cc: <linux-modules@vger.kernel.org>
> ---
>  kernel/module/decompress.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/kernel/module/decompress.c b/kernel/module/decompress.c
> index 474e68f0f063..36f52a232a12 100644
> --- a/kernel/module/decompress.c
> +++ b/kernel/module/decompress.c
> @@ -17,16 +17,16 @@
>  static int module_extend_max_pages(struct load_info *info, unsigned int extent)
>  {
>  	struct page **new_pages;
> +	unsigned int new_max = info->max_pages + extent;
>  
> -	new_pages = kvmalloc_array(info->max_pages + extent,
> -				   sizeof(info->pages), GFP_KERNEL);
> +	new_pages = kvrealloc(info->pages,
> +			      size_mul(new_max, sizeof(*info->pages)),
> +			      GFP_KERNEL);

Nit: Using the array_size() alias of size_mul() might be clearer in this
context.

It looks ok to me in any case.

Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>

-- 
Thanks,
Petr