Re: [PATCH 1/2] fs: ubifs: zero initialize allocated inode

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hi,

On 5/19/26 2:44 PM, Sascha Hauer wrote:
> UBIFS uses kmem_cache_alloc() to allocate an ubifs_inode. The memory
> returned from kmem_cache_alloc() is not zeroed. ubifs_alloc_inode()
> zeroes all fields in the ubifs_inode except the embedded struct inode.
> In Linux this is done in the kmem_cache constructor function which calls
> inode_init_once(). In barebox we have the constructor function as well,
> but we don't have an equivalent of inode_init_once(), so the constructor
> is empty.  zero the inode in the constructor instead so that barebox
> gets a zeroed inode.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  fs/ubifs/super.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
> index 45037b42ea..4022270d4c 100644
> --- a/fs/ubifs/super.c
> +++ b/fs/ubifs/super.c
> @@ -1128,6 +1128,7 @@ static void kill_ubifs_super(struct super_block *s)
>   */
>  static void inode_slab_ctor(void *obj)
>  {
> +	memset(obj, 0, sizeof(struct inode));

This works because inode is the first member of struct ubifs_inode, but
I would prefer to avoid depending on that as it might change with a
future update.

Can't we just zero all of struct ubifs_inode here to be on the safe side?

Cheers,
Ahmad

>  }
>  
>  static int __init ubifs_init(void)

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