Initial commit — leak-hunt project complete

Five bugs identified and patched in retail Asheron's Call client: - v3b: palette refcount over-increment (3-byte NOP at two sites) - v5: RenderSurface PurgeResource no-op stub (vtable slot 2 thunk) - v11: two dangling-pointer crash guards (NULL-check + reorder) - v14: CEnvCell::Destroy ClipPlaneList leak (18-byte JMP to cleanup thunk) - v22: unpacker stale-pointer SEH guard (whole-function __try/__except) All five ship in leakfix.dll (117 KB, SHA d282f23c…) which is loaded by acclient.exe at process start via PE import table patching by tools/install_leakfix.py. Controlled 15-client fleet soak: unpatched control died at 26h with palette exhaustion; all 14 patched clients survived past that point and reached ≥5-day uptime. Residual ~15 MB/h growth traced to d3d9.dll's internal slab allocator (260KB surface backing buffers retained after Release). See REPORT.md §10 for the full investigation; conclusion is that it's unfixable from outside d3d9. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-23 21:05:17 +02:00 · 2026-05-23 21:05:17 +02:00 · 57b5e43d0e
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+# Iter 4 — CPhysicsObj sweep design (DRAFT, NOT YET IMPLEMENTED)
+
+## Goal
+
+Periodically destroy abandoned CPhysicsObj instances to recover the
+residual leak documented in §6.1 of REPORT.md. **Highest-risk patch
+class** (physics-state mutation, same risk profile as v13 which
+killed Larsson at 98 min). Long soak per change is mandatory.
+
+## What iter 3 told us
+
+After 13 minutes on Unkle Leo (PID 16044), a typical scan shows:
+
+```
+total=971 no_parent=546 no_cell=278 orphan_hash=697 both=234 triple=111
+```
+
+So ~11% of all CPhysicsObj instances pass the strict triple predicate.
+On a fresh client triple count is ~100 (startup residual). Growth is
+1-2 candidates per minute during normal play.
+
+Strict-candidate sample dumps confirm:
+- `parent`, `cell`, `hash_next` all NULL ✓
+- `part_array` non-NULL (heap allocation that should be freed)
+- `shadow_objects.data` non-NULL (heap allocation that should be freed)
+- `state` has small bits set (e.g., 0x00000414 — normal active flags)
+
+This matches the v17 owner-vtable diagnostic's "abandoned but heap state
+still allocated" pattern.
+
+## Candidate destruction call
+
+The engine already has correct teardown:
+
+```c
+// EoR 0x005145D0 — CPhysicsObj::Destroy
+void __thiscall CPhysicsObj::Destroy(CPhysicsObj* this);
+```
+
+Per the v17 owner-diag, `CPhysicsObj::Destroy` correctly tears down
+all owned heap state (`CPartArray::DestroyParts`, etc.). The leak is
+that it's never **called** on these abandoned objects.
+
+After Destroy, the CPhysicsObj itself (~408 bytes) needs to be freed
+via `operator delete`.
+
+## Predicate hardening (BEFORE we destroy anything)
+
+The triple predicate may not be conservative enough. Additional
+checks before destroy:
+
+1. **`update_time` is stale** — field at +0xD4 is a long double
+   (timestamp). If less than `now() - 60s`, the object hasn't been
+   touched in a minute. Compare via TimeGetTime() or similar global.
+2. **`state` is not "currently active"** — need to identify which
+   bits indicate "being processed." For now, skip if state has any
+   high bit set.
+3. **`weenie_obj == NULL`** — at +0x?? (need to verify offset).
+   If a weenie-object still owns this physobj, the engine considers
+   it alive even if other tracking is gone.
+4. **`movement_manager == NULL`** — at +0xC4 per acclient.h
+   (LongHashData base 12 + ... + 0xB8 should be it). If there's an
+   active mover, the object is in flight.
+5. **`hooks == NULL`** — at +0xE? — animation hooks pending.
+
+The candidate must pass ALL these AND the iter-3 triple predicate.
+Stricter than iter 3.
+
+## Safety protocol
+
+1. **Throttle:** max 1 destruction per scan cycle (5 min). Even if 100
+   candidates qualify, destroy ONE per scan. Surface latent bugs slowly.
+2. **Sample-first:** for the first 2 hours, LOG candidate addresses
+   but do NOT destroy. Verify the candidates stay candidates over
+   multiple scans (i.e., they're not transient).
+3. **Per-scan budget:** if a destruction succeeds, log address +
+   pre-destroy field dump. If process crashes after, we have the last
+   destroyed object for forensics.
+4. **Kill switch:** check `LEAKFIX_NO_SWEEP=1` env var at scan start.
+   If set, skip destruction. Default ON (=destroy) once code lands.
+5. **Initial test target:** Unkle Leo (current designated guinea pig
+   per CLAUDE.md). One client only. 4-hour soak before declaring safe.
+6. **Failure recovery:** if Unkle Leo crashes within 1 hour of
+   destruction logic enabling, set the env var, restart with sweep
+   disabled, mark iter-4 as failed in memory, do not retry without
+   redesign.
+
+## Implementation outline (when ready)
+
+```cpp
+struct CPhysicsObj {
+    void*       vtable;          // +0x00
+    void*       hash_next;       // +0x04
+    uint32_t    id;              // +0x08
+    void*       netblob_list;    // +0x0C
+    void*       part_array;      // +0x10
+    // ... 12 bytes of player_vector/distance/CYpt
+    void*       sound_table;     // +0x28
+    uint32_t    pad_exam;        // +0x2C
+    void*       script_manager;  // +0x30
+    void*       physics_script;  // +0x34
+    uint32_t    default_script;  // +0x38
+    float       script_intensity;// +0x3C
+    void*       parent;          // +0x40
+    void*       children;        // +0x44
+    char        position[72];    // +0x48
+    void*       cell;            // +0x90
+    uint32_t    num_shadow;      // +0x94
+    char        shadow_arr[16];  // +0x98 — DArray
+    uint32_t    state;           // +0xA8
+    uint32_t    transient_state; // +0xAC
+    // ... floats
+    void*       movement_manager;// +0xC4
+    void*       position_manager;// +0xC8
+    int         last_move_auto;  // +0xCC
+    int         jumped_frame;    // +0xD0
+    double      update_time;     // +0xD4 (8 bytes)
+    // ...
+    void*       weenie_obj;      // +0x??  TBD
+};
+
+typedef void (__fastcall *destroy_fn_t)(CPhysicsObj* self, void* edx);
+constexpr destroy_fn_t CPHYSICSOBJ_DESTROY = (destroy_fn_t)0x005145D0;
+constexpr void* OP_DELETE = (void*)0x005DF15E;
+
+bool is_truly_abandoned(CPhysicsObj* p) {
+    if (p->parent) return false;
+    if (p->cell) return false;
+    if (p->hash_next) return false;
+    if (p->movement_manager) return false;
+    // state mask: bits 0..15 are flags we tolerate; high bits suggest
+    // active processing
+    if ((p->state & 0xFFFF0000) != 0) return false;
+    if (p->weenie_obj) return false;  // need offset verified
+    // update_time stale check
+    double now = get_engine_time();   // need to find this — e.g., 0x????
+    if (now - p->update_time < 60.0) return false;
+    return true;
+}
+
+void sweep_once() {
+    if (env_skip_sweep()) return;
+    // Walk all CPhysicsObj instances...
+    CPhysicsObj* victim = nullptr;
+    for (each CPhysicsObj p) {
+        if (is_truly_abandoned(p)) { victim = p; break; }  // ONLY ONE
+    }
+    if (!victim) return;
+
+    logf("SWEEP destroying CPhysicsObj @ 0x%p (state=0x%08x)", victim, victim->state);
+    dump_physobj((uintptr_t)victim);  // pre-destroy forensics
+    __try {
+        CPHYSICSOBJ_DESTROY(victim, 0);
+        ((void(__fastcall*)(void*, void*))OP_DELETE)(victim, 0);
+        logf("SWEEP ok");
+    } __except (EXCEPTION_EXECUTE_HANDLER) {
+        logf("SWEEP exception — abandoning sweep this scan");
+    }
+}
+```
+
+## Known unknowns to resolve before coding
+
+1. **Engine time global address** — for the stale-`update_time` check
+2. **`weenie_obj` offset** — need to read acclient.h carefully or sample dumps
+3. **State-bit meanings** — which bits indicate "in active processing"
+4. **Does `operator delete` of a CPhysicsObj that already had Destroy() called work?** —
+   Destroy probably tears down state but may not free `this`.
+5. **What if the object is mid-iteration in some other code?** —
+   destroying it would leave dangling iterators. Need to check the
+   render loop / update loop doesn't have outstanding refs.
+
+These are NOT minor — getting any wrong = v13-class crash.
+
+## Recommended path
+
+1. **Iter 4a (logging-only):** add the harder predicates (`movement_manager`,
+   `weenie_obj`, `update_time` stale, state mask). Log candidate count
+   passing the harder set. Compare to iter-3 triple count. If much
+   smaller, predicates are stricter and we have higher confidence.
+2. **Iter 4b (sample-first):** dump 3 candidates that pass the hard
+   set every scan. Verify they look genuinely abandoned across multiple
+   scans.
+3. **Iter 4c (destroy 1 per hour, not per scan):** initial mutation
+   test at the slowest possible rate. Soak 8h+ before declaring safe.
+4. **Iter 4d (destroy N per scan, where N = current candidate count):**
+   only after 4c passes 24h soak.
+
+This is a 3-day minimum process if everything goes right. If a v13-class
+crash happens anywhere, restart from 4a with a redesigned predicate.
+
+## Decision gate
+
+Per the soak data on Unkle Leo:
+- triple candidate growth: ~5/5min = 1/min
+- After 1 hour without sweep: ~60 abandoned physobjs added
+- After 24h: ~1440 abandoned
+- At ~1KB heap state per physobj: ~1.4 MB/day from this exact predicate
+
+Compare to the agent's CObjCell-family estimate of 7-8 MB/hr. The
+triple subset is much smaller than the agent's total. The harder
+predicates will be smaller still.
+
+**Question for the decision-maker (the human):** is recovering
+~1-2 MB/day per active client worth a v13-class risk? Given the
+project's 5-day soak target is already met without iter 4, **the
+honest answer is probably NO** — iter 4 buys marginal improvement
+at meaningful risk.
+
+If the goal is 10-day uptime for heavy looters, iter 4 might help
+but the residual is dominated by other classes (CObjCell, gm*UI
+recycle pool, palette outside v3b's scope).
+
+## Recommendation
+
+**Defer iter 4 indefinitely.** Iter 3 instrumentation gives us data
+to argue for or against. The DLL form's basic patches (v3b/v5/v11/v14)
+are what produces the soak win. Adding sweep is high-risk,
+low-marginal-reward.
+
+Keep this document for future reference if a future analyst decides
+the residual leak warrants the risk.