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[AUDIT-059 R-A] Phase A backward-trace: divergence is sub_822F1AA8 loop exit, not factory/registry

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Round-37 anchor reframe: both engines install the SAME static .rdata vtable
0x820A183C at [0x828E1F08]. Instance VAs differ only because of ε-class
allocator divergence (audit-043). vtable bytes byte-identical; the user
prompt's "factory/registry" framing was falsified.

Phase A walkthrough (rounds A1..A8):
- A.1 canary --audit_jit_prolog_pc=0x821741C8: tid=6, r3=0xBCCC4A80 (= inner
  sub-object of [0x828E1F08]'s singleton), LR=0x822F1D5C (return-from-bctrl
  inside sub_822F1AA8)
- A.2 found tid=6 spawn site sub_821746B0 at PC 0x82174824 spawning
  entry=sub_821748F0 ctx=BC365700/BC366DA0. sub_822F1AA8 ALSO spawns a
  second thread (entry=sub_822F1EE0 ctx=BCE24A40) at PC 0x822F1B08
- A.3 sub_822F1AA8 has 2 callers, both in sub_8216EA68 (its sole caller is
  sub_824AB748 = entry_point)
- A.4 ours mirror probe: sub_821746B0 enters, [0x828E2B14] gate passes,
  ExCreateThread fires returning handle 0x1070 (= tid=13). Ours' tid=13
  IS the same logical thread as canary's spawned silph initializer
- A.5 canary --audit_jit_prolog_pc=0x821749C0: fires only 2× on short-lived
  tid=17, tid=26 (the spawned initializers — NOT tid=6)
- A.6 canary --audit_jit_prolog_pc=0x822F1AA8: fires 1× on tid=6 with
  r3=0xBCE24A40 LR=0x8216EE14 (the second sub_822F1AA8 call site)
- A.7 canary --audit_jit_prolog_pc=0x824AB748 (entry_point): fires on
  tid=00000006. CONFIRMS canary's tid=6 = canary's main thread.

Verdict: identical call chain entry_point → sub_8216EA68 → sub_822F1AA8 in
both engines; same controller (ε-divergent VA, byte-identical fields).
Canary's main thread stays in sub_822F1AA8's dispatcher loop firing
sub_821741C8 ~1678×/30s. Ours' main thread exits the loop and thread-joins
on the spawned initializer (tid=13), which is itself wedged on handle 0x1078
forever.

Loop exit is gated by bit 28 of [r30+0] (the controller's flag word). Same
value 0x21 at function entry in both engines. Some code between entry and
loop check sets bit 28 in ours but not in canary. Mem-watch on 0x40d09a40
shows zero guest stores in ours' 50M parallel run — setter is either a
kernel-side store, computed alias, or probe-quantum-elided JIT store.

Phase B classification: Class 3a (state-divergence on controller object).
The vtable is the same; the controller's bit 28 evolves differently during
sub_822F1AA8 setup. Class 4 (synthesis) is now less attractive since we
correctly reach the dispatcher with the right inputs — we just exit too
soon.

Phase C will need either JIT instrumentation to identify the bit-28 setter,
or a kernel-side hook to clear bit 28 on entry to the loop check site.

Findings notes:
- round-A4b-ours-spawn-gate/FINDINGS.md (spawn topology + tid mapping)
- round-A8-ours-822F1AA8-trace/FINDINGS.md (full loop structure + bit-28 gate)

New reading-error class #18: probe-output anchor misframing (singleton[VA]=X
vtable=Y was misread as "Y is canary-only vtable" when Y is the same
.rdata vtable in both engines).

Branch: iterate-2C/silph-ui-spawn-trace off master @ 229b46c.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
MechaCat02
2026-06-11 17:02:20 +02:00
parent 229b46c765
commit 52c30d82a7
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# Round-A1..A4 findings — canary tid=6 spawn chain & divergence frontier
## Anchor reframe (round-37 misread corrected)
The "factory/registry layer divergence at [0x828E1F08]" framing is falsified.
Both engines install the SAME static-XEX `.rdata` vtable `0x820A183C` at the
singleton's `[+0]`. The instance VAs differ only because of ε-class allocator
divergence (audit-043).
| Probe | Canary | Ours |
|----------------------------|----------------------|----------------------|
| `[0x828E1F08]` | 0xBC22C910 (heap) | 0x40111910 (heap) |
| `[[0x828E1F08]+0]` vtable | 0x820A183C | 0x820A183C (SAME) |
| `vtable[+0]` thunk | 0x82175330 | 0x82175330 (SAME) |
| `vtable[+8]` thunk | 0x82175340 → b sub_821741C8 | SAME (vtable bytes from XEX `.rdata`) |
The thunks at 0x82175330+ are 8-byte `lwz r3, 8(r3); b <real_method>`
trampolines. Slot 2 (`+0x08`) is the worker dispatch entry that round 33
identified as 471× in canary tid=6 / 0× in ours.
## A.1 — Canary dispatcher loop is in sub_822F1AA8 on tid=6
Probe `--audit_jit_prolog_pc=0x821741C8 --audit_jit_prolog_r3_bytes=256` on
canary (35 s):
- ~1678 fires of sub_821741C8 on **tid=6**
- r3 at entry = `0xBCCC4A80` (the inner sub-object of the silph::UImpl
singleton — extracted via the thunk's `lwz r3, 8(r3)`)
- LR at entry = `0x822F1D5C` (return PC after the `bctrl` at 0x822F1D58 inside
sub_822F1AA8)
- Singleton's `[+C0..+D0]` UTF-16 spells "HF Frequency" (a UI label)
The dispatch site in canary (the `bctrl`) is at PC 0x822F1D58 inside
sub_822F1AA8:
```
0x822F1D40: lwz r3, 7944(r25) ; r3 = [r25+0x1F08] = [0x828E1F08]
0x822F1D4C: lwz r11, 0(r3) ; vtable
0x822F1D50: lwz r11, 8(r11) ; vtable[+8] = thunk 0x82175340
0x822F1D54: mtctr r11
0x822F1D58: bctrl ; → 0x82175340 → b 0x821741C8
```
## A.2 — Canary tid=6 spawn site is sub_821746B0 at PC 0x82174824
Enumeration of `ExCreateThread` calls in canary (35 s, 21 unique tuples):
```
entry=821748F0 start_ctx=BC365700 lr=824AC5F0 guest_lr=82174828 ← silph dispatcher #1
entry=821748F0 start_ctx=BC366DA0 lr=824AC5F0 guest_lr=82174828 ← silph dispatcher #2
```
PC `0x82174824` is the `bl 0x82172370` (the `ExCreateThread` thunk) inside
`sub_821746B0`. The setup is:
```
0x8217480C: lis r11, 0x8217
0x82174810: li r7, 0
0x82174814: li r6, 4 ; priority
0x82174818: mr r5, r29 ; start_ctx
0x8217481C: addi r4, r11, 18672 ; r4 = 0x821748F0 (entry)
0x82174820: li r3, 0
0x82174824: bl 0x82172370 ; ExCreateThread
```
The entry `0x821748F0` is a thread main that calls `bl 0x821749C0` (the
inner dispatch).
## A.3 — sub_822F1AA8 spawns a SECOND thread at 0x822F1B08
The dispatch-loop function `sub_822F1AA8` itself ALSO spawns a thread at
PC 0x822F1B08 with entry=`sub_822F1EE0` and `start_ctx=BCE24A40`:
```
0x822F1AEC: lis r11, 0x822F
0x822F1AFC: addi r4, r11, 7904 ; r4 = 0x822F1EE0
0x822F1B08: bl 0x82172370 ; ExCreateThread
```
sub_822F1EE0 → sub_822F1F20 contains its own atomic state-machine + wait loop.
## A.3' — sub_822F1AA8 has exactly 2 callers, both in sub_8216EA68
```
source=0x8216ECCC source_func=0x8216EA68 kind=call
source=0x8216EE10 source_func=0x8216EA68 kind=call
```
So sub_8216EA68 is the only function that drives sub_822F1AA8.
## A.4 — Ours' divergence is INSIDE the spawned thread, NOT at the spawn
Mirror-probed ours at `sub_821746B0` body BB heads (parallel mode, 50M
instructions, XENIA_CACHE_PERSIST=1):
| PC | Fires | Notes |
|-------------|-------|------------------------------------------------|
| 0x821746B0 | 1 | Entry. r3=0x40ba9a80 |
| 0x821746E0 | 1 | After `bl 0x8284DCFC` (critical-section) |
| 0x82174798 | 1 | After the early `beq` (r28==0 branch) |
| 0x821747B8 | 1 | **Past the gate**: `[0x828E2B14]=0x40105000` non-NULL; `bl 0x82150EF8` returned r3=0x4024a840 (NON-NULL) |
| 0x821747D8 | 1 | After the inner `bl 0x821723F0` |
| 0x8217480C | 1 | Enters the spawn block |
| 0x82174828 | 1 | **Post-`bl ExCreateThread`**, r3=0x1070 = thread handle |
**OURS DOES SPAWN THE THREAD VIA THIS SITE.** The returned handle 0x1070 is
**tid=13's thread handle** (per round 37 final state). So **ours' tid=13 IS
the same logical thread as canary's tid=6** — spawned by the identical call
site with the same entry (0x821748F0).
## A.4 — Divergence is INSIDE the spawned thread's body
Round 37's frame trail for ours' tid=13 wedge:
`0x821CB1E0 → 0x821CBAE0 → 0x821CC454 → 0x821C4F18 → 0x82174A80`
The LAST frame `0x82174A80` is **inside sub_821749C0** (= the inner dispatch
called from sub_821748F0). It's right after the vtable dispatch at
0x82174A78 (`bctrl` on `[r30+vtable][+16]`):
```
0x82174a64: mr r3, r30 ; r3 = some object
0x82174a68: lwz r11, 0(r30)
0x82174a6c: lwz r4, 4(r29)
0x82174a70: lwz r5, 8(r31)
0x82174a74: lwz r11, 16(r11) ; r11 = vtable[+0x10]
0x82174a78: mtctr r11
0x82174a7c: bctrl ; dispatch
0x82174a80: lwz r3, 0(r29) ; ← wedge frame top (LR after bctrl)
```
So `sub_821749C0`'s vtable[+0x10] dispatch on tid=13/tid=6's `r30` object
lands at audit-049 territory in ours (chain through sub_821CB030+0x128 that
ends waiting forever on handle 0x1078). In canary, the same dispatch on the
same object SHOULD land somewhere that ultimately reaches sub_822F1AA8's
dispatch loop and runs sub_821741C8 1678× via vtable[+8].
**The object `r30` is the result of `bl 0x821CF3F0`** at PC 0x821749DC. So
sub_821CF3F0 returns a registry-lookup object; the vtable on this object's
slot +0x10 method's body determines whether the thread wedges or runs.
## Phase B classification
Class 3 — **Missing init-time precondition**. Ours reaches the spawn site,
ours' tid=13 enters the chain, ours' tid=13 enters sub_821749C0, but the
vtable[+0x10] dispatch at PC 0x82174A78 in ours lands in audit-049 territory
(wait forever on 0x1078) rather than continuing through the canonical chain
toward sub_822F1AA8's outer dispatch loop.
Possible classes to refine in next round:
- **3a**: same vtable but state-dependent — `r30`'s field at a specific offset
differs in ours vs canary, causing the method body to take a different
branch.
- **3b**: the vtable in `r30` is DIFFERENT in ours vs canary (e.g., ours has
a base-class vtable but canary has a derived-class vtable).
- **4**: synthesis fallback — spawn a SECOND thread that runs sub_822F1AA8's
dispatch loop directly, bypassing the wedged sub_821749C0 chain.
## Next probe (A.4.5)
Probe both engines at sub_821749C0 entry filtering tid=13 (ours) / tid=6
(canary), capturing:
- `r3` and `r4` at entry (the factory-output object and the ctx)
- After the `bl 0x821CF3F0` at 0x821749DC: capture r30 (= sub_821CF3F0
return — the object whose vtable is dispatched at 0x82174A78)
- At PC 0x82174A78 (the divergent bctrl): r30 + r30+0 (vtable) + vtable[+0x10]
(the dispatch target)
If ours and canary have IDENTICAL `vtable[+0x10]` targets but the method
body's behavior differs → class 3a (state divergence). If targets differ →
class 3b (vtable identity divergence).

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AUDIT-PC-PROBE pc=0x821746b0 tid=1 hw=0 cycle=9228833 lr=0x82173c38 r3=0x40ba9a80 r11=0x00000000 [r3+0]=0x40111910 [[r3+0]+24]=0x00000000 [r3+0x0C]=0x00000000 [r3+0x30]=0x00000000
AUDIT-MEM-READ addr=0x828e2b14 val=0x40105000 vtable=0x40105004 vtable[0]=0x40105008 vtable[24]=0x40105020 pc=0x821746b0 tid=1 cycle=9228833
AUDIT-PC-PROBE pc=0x821746e0 tid=1 hw=0 cycle=9228856 lr=0x821746e0 r3=0x00000000 r11=0x00000000 [r3+0]=0x00000000 [[r3+0]+24]=0x00000000 [r3+0x0C]=0x00000000 [r3+0x30]=0x00000000
AUDIT-MEM-READ addr=0x828e2b14 val=0x40105000 vtable=0x40105004 vtable[0]=0x40105008 vtable[24]=0x40105020 pc=0x821746e0 tid=1 cycle=9228856
AUDIT-PC-PROBE pc=0x82174798 tid=1 hw=0 cycle=9228859 lr=0x821746e0 r3=0x00000000 r11=0x00000000 [r3+0]=0x00000000 [[r3+0]+24]=0x00000000 [r3+0x0C]=0x00000000 [r3+0x30]=0x00000000
AUDIT-MEM-READ addr=0x828e2b14 val=0x40105000 vtable=0x40105004 vtable[0]=0x40105008 vtable[24]=0x40105020 pc=0x82174798 tid=1 cycle=9228859
AUDIT-PC-PROBE pc=0x821747b8 tid=1 hw=0 cycle=9229012 lr=0x821747ac r3=0x4024a840 r11=0x4024a840 [r3+0]=0x4024ace0 [[r3+0]+24]=0x43777290 [r3+0x0C]=0x4024a820 [r3+0x30]=0x4250dec0
AUDIT-MEM-READ addr=0x828e2b14 val=0x40105000 vtable=0x40105004 vtable[0]=0x40105008 vtable[24]=0x40105020 pc=0x821747b8 tid=1 cycle=9229012
AUDIT-PC-PROBE pc=0x821747d8 tid=1 hw=0 cycle=9229440 lr=0x821747cc r3=0x4024a840 r11=0xffffffff [r3+0]=0x40ba9a80 [[r3+0]+24]=0x00000000 [r3+0x0C]=0x00000000 [r3+0x30]=0x4250dec0
AUDIT-MEM-READ addr=0x828e2b14 val=0x40105000 vtable=0x40105004 vtable[0]=0x40105008 vtable[24]=0x40105020 pc=0x821747d8 tid=1 cycle=9229440
AUDIT-PC-PROBE pc=0x8217480c tid=1 hw=0 cycle=9229443 lr=0x821747cc r3=0x4024a840 r11=0xffffffff [r3+0]=0x40ba9a80 [[r3+0]+24]=0x00000000 [r3+0x0C]=0x00000000 [r3+0x30]=0x4250dec0
AUDIT-MEM-READ addr=0x828e2b14 val=0x40105000 vtable=0x40105004 vtable[0]=0x40105008 vtable[24]=0x40105020 pc=0x8217480c tid=1 cycle=9229443
AUDIT-PC-PROBE pc=0x82174828 tid=1 hw=0 cycle=9229509 lr=0x82174828 r3=0x00001070 r11=0x824b0000 [r3+0]=0x00000000 [[r3+0]+24]=0x00000000 [r3+0x0C]=0x00000000 [r3+0x30]=0x00000000
AUDIT-MEM-READ addr=0x828e2b14 val=0x40105000 vtable=0x40105004 vtable[0]=0x40105008 vtable[24]=0x40105020 pc=0x82174828 tid=1 cycle=9229509
=== Final State ===
PC: 0x824ac578
LR: 0x824ac578
CTR: 0x82153bf0
CR: 0x24000028
XER: CA=0 OV=0 SO=0
r0 : 0x0000000082153bf0
r1 : 0x00000000700ff6e0
r2 : 0x0000000020000000
r4 : 0x0000000000000001
r7 : 0x0000000003a72328
r8 : 0x0000000043b77284
r9 : 0x0000000043b77328
r10: 0x0000000000000001
r11: 0x0000000000000103
r12: 0x0000000082173c64
r13: 0x000000007fff0000
r18: 0x0000000040d09a7c
r23: 0x00000000828f3844
r26: 0x000000004024a620
r27: 0x00000000820a17a8
r31: 0x0000000000001070
=== Thread diagnostics ===
hw=0 idx=0 tid=1 state=Blocked(WaitAny { handles: [4208], deadline: None }) pc=0x824ac578 lr=0x824ac578 sp=0x700ff6e0
r0=0x82153bf0 r3=0x00000000 r4=0x00000001 r5=0x00000000 r6=0x00000000 r7=0x03a72328
r8=0x43b77284 r9=0x43b77328 r10=0x00000001 r11=0x00000103 r12=0x82173c64 r13=0x7fff0000
hw=0 idx=1 tid=11 state=Blocked(WaitAny { handles: [2190094916, 2190094880], deadline: None }) pc=0x824d2a94 lr=0x824d2a94 sp=0x71497d90
r0=0x00000000 r3=0x00000000 r4=0x71497de0 r5=0x00000001 r6=0x00000003 r7=0x00000001
r8=0x00000000 r9=0x00000000 r10=0x71497df0 r11=0x828a3244 r12=0xbcbcbcbc r13=0x4b9f1000
hw=1 idx=0 tid=2 state=Blocked(WaitAny { handles: [2189887804], deadline: None }) pc=0x824a95f8 lr=0x824a95f8 sp=0x710ffd20
r0=0x0000030c r3=0x00000000 r4=0x00000003 r5=0x00000001 r6=0x00000000 r7=0x00000000
r8=0x00000001 r9=0x6f000000 r10=0x824a9178 r11=0x82870000 r12=0x824a94f0 r13=0x4acc3000
hw=1 idx=1 tid=13 state=Blocked(WaitAny { handles: [4216], deadline: None }) pc=0x824ac578 lr=0x824ac578 sp=0x715a7a20
r0=0x821511d0 r3=0x00000000 r4=0x00000001 r5=0x00000000 r6=0x00000000 r7=0x03a723d0
r8=0x43b77334 r9=0x43b77334 r10=0x40541f80 r11=0x00000001 r12=0x821cb1e0 r13=0x4d1d4000
hw=2 idx=0 tid=7 state=Blocked(WaitAny { handles: [1111821148], deadline: Some(42946672) }) pc=0x824cd4f4 lr=0x824cd4f4 sp=0x71187e60
r0=0x00000000 r3=0x00000000 r4=0x00000003 r5=0x00000001 r6=0x00000000 r7=0x71187eb0
r8=0x00000000 r9=0x00000000 r10=0x00000002 r11=0x00000002 r12=0xbcbcbcbc r13=0x4b1d6000
hw=2 idx=1 tid=8 state=Blocked(WaitAny { handles: [4176, 4132], deadline: None }) pc=0x824ab214 lr=0x824ab214 sp=0x71287c90
r0=0x00000000 r3=0x00000000 r4=0x71287cf0 r5=0x00000001 r6=0x00000001 r7=0x00000000
r8=0x00000000 r9=0x00009030 r10=0x00000002 r11=0x00000020 r12=0x822f1ff0 r13=0x4b90a000
hw=3 idx=0 tid=4 state=Blocked(WaitAny { handles: [4120], deadline: None }) pc=0x824ac578 lr=0x824ac578 sp=0x7112fb80
r0=0x821511a0 r3=0x00000000 r4=0x00000001 r5=0x00000000 r6=0x00000000 r7=0x03a723d0
r8=0x43b7732c r9=0x828f0000 r10=0x00000008 r11=0x00000000 r12=0x8245a660 r13=0x4adc6000
hw=3 idx=1 tid=5 state=Blocked(WaitAny { handles: [4224], deadline: None }) pc=0x824ac578 lr=0x824ac578 sp=0x7116fbe0
r0=0x821511a0 r3=0x00000000 r4=0x00000001 r5=0x00000000 r6=0x00000000 r7=0x03a723d0
r8=0x43b7732c r9=0x828f0000 r10=0x00000001 r11=0x00000000 r12=0x82458b34 r13=0x4adc8000
hw=4 idx=0 tid=9 state=Ready pc=0x824d140c lr=0x824d22b4 sp=0x71387df0
r0=0x00000000 r3=0x4250dedc r4=0x4250e040 r5=0x00000001 r6=0x00000000 r7=0x00000000
r8=0x4b9ec000 r9=0x01010000 r10=0x01010000 r11=0x00000000 r12=0x824d22a8 r13=0x4b9ec000
hw=5 idx=0 tid=3 state=Blocked(WaitAny { handles: [4112], deadline: None }) pc=0x824ac578 lr=0x824ac578 sp=0x7111fdf0
r0=0x82153bf0 r3=0x00000000 r4=0x00000001 r5=0x00000000 r6=0x00000000 r7=0x00000a10
r8=0x00000010 r9=0x00000000 r10=0x00009030 r11=0x00000000 r12=0x82181988 r13=0x4adc4000
hw=5 idx=1 tid=6 state=Ready pc=0x824ab214 lr=0x824ab214 sp=0x7117fc60
r0=0x821511a0 r3=0x00000001 r4=0x7117fcc0 r5=0x00000001 r6=0x00000001 r7=0x00000000
r8=0x7117fcb0 r9=0x00009030 r10=0x00000002 r11=0x00000020 r12=0x82458d68 r13=0x4adca000
hw=5 idx=2 tid=10 state=Ready pc=0x824d140c lr=0x824d22b4 sp=0x71487e00
r0=0x00000000 r3=0x4250dedc r4=0x4250e040 r5=0x00000001 r6=0x00000000 r7=0x00000000
r8=0x4b9ee000 r9=0x01010000 r10=0x01010000 r11=0x00000000 r12=0x824d22a8 r13=0x4b9ee000
hw=5 idx=3 tid=12 state=Ready pc=0x824aa6a4 lr=0x824aa6a4 sp=0x714a7da0
r0=0x00000000 r3=0x000000ff r4=0x00000020 r5=0x714a7df4 r6=0x00000000 r7=0x00000000
r8=0x00000000 r9=0x00000000 r10=0x00000000 r11=0x00000001 r12=0x8217898c r13=0x4d1d2000
-- Handle waiter lists --
handle=0x00001024 Semaphore(0/2147483647) waiters(tid)=[8]
handle=0x00001010 Event(sig=false, mr=true) waiters(tid)=[3]
handle=0x00001070 Thread(id=13, exit=None) waiters(tid)=[1]
handle=0x00001080 Event(sig=false, mr=false) waiters(tid)=[5]
handle=0x828a3244 Event(sig=false, mr=false) waiters(tid)=[11]
handle=0x00001018 Semaphore(0/2147483647) waiters(tid)=[4]
handle=0x00001050 Event(sig=false, mr=true) waiters(tid)=[8]
handle=0x00001078 Event(sig=false, mr=false) waiters(tid)=[13]
handle=0x8287093c Event(sig=false, mr=false) waiters(tid)=[2]
handle=0x828a3220 Event(sig=false, mr=true) waiters(tid)=[11]
handle=0x42450b5c Event(sig=false, mr=true) waiters(tid)=[7]