FABRIC.md: item 4.5d -- Finding 3 (muldiv64) root-caused and fixed via QEMU tracing, Finding 4 blocks

Browse Source

Used QEMU-side instrumentation (-d int tracing, plus a working chardev-based
monitor -- the older bareword -monitor syntax silently fails on QEMU
10.2.1) as directed. The PM Timer "stall" was never a hang: it was a #DE
divide error cascading to a triple fault, which -no-reboot converts into a
silent clean QEMU exit -- indistinguishable from a hang without tracing,
and why arch_relax() (solving a hang that didn't exist) had no effect.
Root cause and fix documented in full (also see commit b43e51a).

With the fix, amd64 boot at -O2 now proceeds far past the original stall --
through capsule birth and into Hermes's word registration -- before hitting
a second, different fault (Finding 4): a direct #GP at IDT index 32
(APIC_TIMER_VECTOR), not yet root-caused. Same silent-triple-fault-exit
shape, so this was very likely bundled into "the hang" before tracing
distinguished the two separate bugs.

-O2 reverted again (uncommitted); muldiv64's fix is kept, real and
independently verified at unchanged -O0 on all three architectures.
Routine three-arch artifacts from this session's verification runs
included.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

...

This commit is contained in:

Robert Allan James

2026-08-11 12:17:23 -04:00

co-authored by Claude Sonnet 5

parent b43e51a95d

commit 1c5e926c3f

18 changed files with 104344 additions and 77 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download Patch File Download Diff File Expand all files Collapse all files

disk/artemis.img

BIN

Binary file not shown.