Matthew Leach 39a5ef331d libkernel/slab: fix UB and accounting bugs identified by Miri ...

Fix several issues in the slab allocator identified by the heap stress
tests (intermittent) and running the tests under Miri.

1. Fix Undefined Behavior. Previously, the allocator created temporary
   `&mut Frame` references while raw pointers to that frame existed in the
   intrusive `partial` or `free` lists. Under Miri's strict aliasing rules,
   creating a unique reference to the whole struct invalidated the list
   pointers.

   The fix implements "split borrowing": we now maintain raw pointers to
   the frame and only create mutable references to the `.state` field
   when needed, ensuring the `.link` field remains valid for the
   intrusive list.

2. Fix `free_list_sz` accounting. In `try_alloc`, the `free_list_sz`
   counter was not being decremented when a slab was successfully popped
   from the free list. This caused the allocator to believe it had free
   slabs when the list was actually empty, leading to panics during
   batch-free operations.

3. Increase heap stress tests. The test suite now runs the stress test
   in a loop to catch state persistence bugs and ensures the allocator is
   fully torn down and reset between iterations.

Fixes: #220

2026-02-21 14:38:18 -08:00

..

src

libkernel/slab: fix UB and accounting bugs identified by Miri

2026-02-21 14:38:18 -08:00

Cargo.toml

enable clippy lints for libkernel

2026-02-13 10:24:13 -08:00