Re: [PATCH] ntfs3: align struct ATTR_LIST_ENTRY

[Randy Dunlap]

On 12/7/23 06:28, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
> 
> On architectures like i386 that don't enforce natural alignment of u64
> struct members, so the recent change to remove the final 48 bits
> reduced the structure size from 32 to 28 bytes:
> 
> include/linux/build_bug.h:78:41: error: static assertion failed: "sizeof(struct ATTR_LIST_ENTRY) == 0x20"
> fs/ntfs3/ntfs.h:530:1: note: in expansion of macro 'static_assert'
>   530 | static_assert(sizeof(struct ATTR_LIST_ENTRY) == 0x20);
>       | ^~~~~~~~~~~~~
> 
> Add an alignment attribute that makes the structure the same across
> all architectures again.
> 
> Fixes: d155617006eb ("fs/ntfs3: Fix detected field-spanning write (size 8) of single field "le->name"")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>


Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Tested-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> # build-tested

Thanks.

> ---
>  fs/ntfs3/ntfs.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/ntfs3/ntfs.h b/fs/ntfs3/ntfs.h
> index c8981429c721..2d409ac94cbb 100644
> --- a/fs/ntfs3/ntfs.h
> +++ b/fs/ntfs3/ntfs.h
> @@ -525,7 +525,7 @@ struct ATTR_LIST_ENTRY {
>  	__le16 id;		// 0x18: struct ATTRIB ID.
>  	__le16 name[];		// 0x1A: To get real name use name_off.
>  
> -}; // sizeof(0x20)
> +} __aligned((8)); // sizeof(0x20)
>  
>  static_assert(sizeof(struct ATTR_LIST_ENTRY) == 0x20);
>  

-- 
~Randy