On Wed, Aug 27, 2025 at 11:28:32PM +0000, ノウラ | Flare via GitGitGadget wrote:

From: =?UTF-8?q?=E3=83=8E=E3=82=A6=E3=83=A9=20=7C=20Flare?=
 [off-list ref]

clear_alloc_state() freed all slabs and nulled the slabs pointer but
left slab_alloc, nr, and p unchanged. If the alloc_state is reused,
ALLOC_GROW() can wrongly assume that the slab array is already
allocated because slab_alloc still holds a stale nonzero capacity.
In that case s->slabs remains NULL and the next dereference writes
through a NULL pointer, causing undefined behavior.

This is good.

To fix this, this patch:

Style nit, we tend to use the "imperative form" here in Git,
like this:

- Rename allocate_alloc_state() → alloc_state_alloc().
- Replace ...
- Update ...

- Renames allocate_alloc_state() → alloc_state_alloc().
- Replaces the “just clear” API with
  alloc_state_free_and_null(struct alloc_state **s_),
  which frees all slabs and the alloc_state itself,
  and then nulls the caller’s pointer.
- Updates call sites to use the new helpers and drops
  redundant FREE_AND_NULL() calls.

This makes the alloc_state lifecycle API harder to misuse,
eliminates stale-capacity state,
and aligns naming with project conventions.