Robert Allan JamesandClaude Sonnet 5
70421bdd43
The interpreter_enabled guard added in the previous commit (662ef44) was a
real but incomplete fix -- re-running the exact repro against it still
panicked (this time as a raw #PF page fault), proving something deeper
was wrong.
Root cause, found via targeted console_puts probes (not GDB --
starkernel_kernel.elf's symbols don't correspond to the actual running
starkernel_loader.efi binary for this monolithic build, same gotcha
already on record from the 2026-08-18 aarch64 investigation):
sk_repl_run()'s main loop captures `active` once, before calling
sk_console_readline(), which then blocks for the next full line. If the
identity `active` points at is killed while that read is still blocked,
the bailout meant to catch this (sk_console_identity_present()) only
checks a generic "is anyone attached" boolean, not "is the specific
identity active belonged to still attached" -- a fast detach of one
identity followed by attach of a different one never produces an
observable gap in that boolean, so the bailout never fires. The stale
`active`, now pointing at freed memory, gets dispatched into.
Fix: re-resolve `active` fresh from g_repl_active_vm immediately before
dispatch, right after sk_console_readline() returns. One line, no
registry lookup, no dereference of the stale pointer -- closes the race
regardless of whether the bailout catches it first.
Verified: rebuilt amd64 clean, reproduced the exact same attach/USE/
detach/attach/USE sequence against the fixed build -- clean switch, no
fault, exerciser runs correctly afterward.
FABRIC-3.md §XII.2 also corrected to stop claiming the interpreter_
enabled guard alone closed the crash -- it didn't, per the above.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EXieurDfDSsDFdnSyusuWo
capsules/
FORTH personality files loaded by the VM at boot. A capsule is an immutable, content-addressed payload; its XXHash64 hash is its identity. Any mutation changes the hash and the birth protocol rejects the image.
Key files
| File | Type | Purpose |
|---|---|---|
init.4th |
(m) MAMA_INIT |
Default Mama VM personality — loaded at LBN 2048 |
ACL.4th |
user | Word-level ACL system; self-activating at boot |
zuse.4th |
user | Bootstrap superuser; loaded by ACL.4th |
doe.4th |
user | DoE workload words (EXEC-DOE) — opt-in |
init-0.4th … init-9.4th |
(p) |
Numbered personality variants |
init-l8-*.4th |
(p) |
L8 Jacquard mode variants (stable/volatile/diverse/temporal/transition/omni) |
hermes/init.4th |
(p) |
Hermes baby VM personality |
artemis/init.4th |
(p) |
Artemis baby VM personality |
Block namespace
Block ranges are shared across all loaded capsules — collisions cause silent word-definition overwrites.
| Range | Owner |
|---|---|
| 2048–2099 | init.4th |
| 2100–2199 | doe.4th |
| 3000–3999 | workload capsules |
| 4000+ | user-defined (ACL.4th, zuse.4th, …) |
Each block is limited to 1024 bytes. Verify with wc -c before committing.
See also
experiments/bare_metal/README.md— DoE protocols and block namespace rulesdocs/03-architecture/word-acl/DESIGN.md— ACL system designtools/mkcapsule.c— assembles capsules intocapsule_generated.c- Project root