sk_v4_grow.c's dev_rw4k computes 1 KiB block numbers as (uint32_t)devblock * 4,
which wraps past 4 TiB; Artemis is capped at 256 GiB (STICK_ARTEMIS_CAP_GIB,
kernel/Makefile), so it is latent -- but nothing said so where the cast is. Now
a compile-time check there (the C99 negative-array pattern the tree uses): a
cap past 4 TiB stops the build, and a cap not defined at all is an #error, not
a skipped check. gpt.c's casts are bounded by the disk's own size, itself a
32-bit count of 1 KiB blocks, checked before each: each now says so.
kernel/tests' check_cap, seen to fail first (a 4096 GiB cap built); now 3
checks, 0 failures -- 256 GiB builds, 4096 GiB and none refused. Built for
amd64, aarch64, riscv64. The plan's increments 2 and 3 marked.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017RzZgrf7V7Zk2iczBXDRbm
Captain Bob, 2026-11-12: "Build an appropriate test harness! Love the idea."
The kernel had no tests below the boots, so defects QEMU cannot provoke could
not be tested first. Plan: docs/v4.0.0/plans/2026-11-12-kernel-host-tests.md.
kernel/tests/: one host program per kernel source, built with that source as
it is, the kernel's flags (-std=c99 -Wall -Wextra -Werror), and fakes --
the console captured line by line, a deterministic RNG that can fail, and a RAM
disk whose reads, writes or flushes fail at chosen 1 KiB blocks.
make -C kernel/tests test runs them; SRC_<test>= runs a test against other
code, which is how a test is seen to fail against the code before a fix.
test_gpt.c, 12 checks: a table written and read back; 16, 17 and 18 used
entries against max 16 and an entry out of range after the 16th (#180); the
RNG, the first write, a later write and a flush failing (#168). Against gpt.c
before #168 and #180: 4 failures, each defect caught. Now: 0. Both runs in
logs/.../kernel-tests/. Not yet a protocol stage: to rule (the plan, step 5).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017RzZgrf7V7Zk2iczBXDRbm
Claude