# Re: \[PATCH v2 49/63\] btrfs: Use memset\_startat() to clear end of struct

- From: David Sterba \<hidden\>
- Date: 2021-08-18 09:32:57 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/08/1481499
- Thread: https://ratatoskr.run/linux-btrfs/2021/08/1481249/t.md

```text
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 <redacted>
> Cc: Josef Bacik <josef@toxicpanda.com>
> Cc: David Sterba <dsterba@suse.com>
> Cc: <redacted>
> Signed-off-by: Kees Cook <redacted>

Acked-by: David Sterba <dsterba@suse.com>
```