On Mon, 28 Sep 2026 23:17:37 +0000 Bill Wendling <[email protected]> wrote:
> The '__counted_by' and '__counted_by_ptr' attributes associate a
> flexible array member or pointer member with a struct field that holds
> its element count. Supporting compilers use these annotations to
> compute dynamic object sizes via '__builtin_dynamic_object_size()' and
> perform runtime bounds checking with KASAN.
>
> Add KUnit tests ('counted_by_flex_oob_access' and
> 'counted_by_ptr_oob_access', guarded by CONFIG_CC_HAS_COUNTED_BY and
> CONFIG_CC_HAS_COUNTED_BY_PTR respectively) to verify that:
>
> - '__builtin_dynamic_object_size()' returns the expected byte size for
> annotated flexible array and pointer members.
> - KASAN detects out-of-bounds read and write accesses beyond the
> annotated count.
>
> Allocate the test structures in 'noinline' helpers and hide the
> returned pointers with OPTIMIZER_HIDE_VAR() so allocation-size
> attributes and compiler optimizations do not mask the '__counted_by'
> and '__counted_by_ptr' checks.
Thanks. Are any of Sashiko's comments pertinent?
https://sashiko.dev/#/patchset/[email protected]
