CVE-2026-23223

In the Linux kernel, the following vulnerability has been resolved:

xfs: fix UAF in xchk_btree_check_block_owner

We cannot dereference bs->cur when trying to determine if bs->cur
aliases bs->sc->sa.{bno,rmap}_cur after the latter has been freed.
Fix this by sampling before type before any freeing could happen.
The correct temporal ordering was broken when we removed xfs_btnum_t.