Re: BUG #17847: Unaligned memory access in ltree_gist

On Sat, Mar 18, 2023 at 10:00 AM Alexander Lakhin <exclusion@gmail.com> wrote:
> 16.03.2023 22:35, Tom Lane wrote:
>
> I wonder which other opclasses besides ltree have the same issue.
>
>
> I found no other similar places: siglen is also accepted by opclasses
> gist__intbig_ops, gist_hstore_ops, gist_trgm_ops, tsvector_ops,
> which implementations use functions
> _intbig_alloc, ghstore_alloc, gtrgm_alloc, gtsvector_alloc,
> and none of them adds siglen to a pointer.
> Quick testing confirms that.
>
> (gist__ltree_ops uses ltree_gist_alloc(), but the problematic branch
> "if (left) ..." not reached for gist__ltree_ops)

Yep, ltree seems the only place storing aligned value *after*
signature.  Thank you for validating this.

------
Regards,
Alexander Korotkov