Re: [PATCH v2 49/63] btrfs: Use memset_startat() to clear end of struct

[David Sterba]

On Tue, Aug 17, 2021 at 11:05:19PM -0700, Kees Cook wrote:
> In preparation for FORTIFY_SOURCE performing compile-time and run-time
> field bounds checking for memset(), avoid intentionally writing across
> neighboring fields.
> 
> Use memset_startat() so memset() doesn't get confused about writing
> beyond the destination member that is intended to be the starting point
> of zeroing through the end of the struct.
> 
> Cc: Chris Mason <clm@xxxxxx>
> Cc: Josef Bacik <josef@xxxxxxxxxxxxxx>
> Cc: David Sterba <dsterba@xxxxxxxx>
> Cc: linux-btrfs@xxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

Acked-by: David Sterba <dsterba@xxxxxxxx>