v0.10.1: Integration Audit -- Subsystem Connectivity Hardening

VeridianOS v0.10.1 -- Integration Audit: Subsystem Connectivity Hardening

Release Date: February 28, 2026
Commits: 3 (2 fix + 1 chore)
Files Changed: 12 (7 kernel + 5 docs/config)
Lines: +290/-43

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Overview

v0.10.1 is a post-Phase 7 integration audit release that ensures all subsystems introduced across Phases 1--7 are properly connected to their consumers. Two systematic audit passes identified and resolved 51 disconnected code paths where implementations existed but were unreachable from the syscall dispatch table, socket routing layer, PCI probe chain, or process lifecycle hooks.

No new features are introduced. All changes wire existing, tested code into the correct call paths.

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Integration Audit Pass 1 (commit 286000a)

46 Unreachable Syscalls Wired

Systematic audit of the syscall dispatch table (kernel/src/syscall/mod.rs) found 46 syscall variants returning Err(SyscallError::NotImplemented) despite having fully working handler functions. All 46 were connected to their implementations:

• Filesystem (18): open, close, read, write, seek, stat, fstat, mkdir, rmdir, unlink, rename, truncate, chmod, chown, readdir, dup, dup2, pipe
• Process (8): fork, exec, waitpid, getpid, getppid, setpgid, getpgid, setsid
• Memory (4): mmap, munmap, mprotect, brk
• Signals (4): kill, sigaction, sigprocmask, sigsuspend
• Network (6): socket, bind, connect, listen, accept, sendto
• IPC (3): shmget, shmat, shmdt
• Misc (3): ioctl, getcwd, chdir

COW Fork Connected to Page Fault Handler

Copy-on-write fork (process/fork.rs) produced COW-mapped pages but the page fault handler (mm/vmm.rs) did not resolve COW faults. The handler now detects write faults on COW pages, allocates a new frame, copies content, and remaps with write permission.

Audio Pipeline End-to-End

The play shell command parsed WAV files and mixed audio but never delivered samples to the VirtIO-Sound device. The audio output pipeline now routes mixed samples through the ring buffer transport to virtio_sound::write_pcm_data().

Bootstrap Init Calls Verified

All 8 init() calls in bootstrap.rs verified as real implementations (not stubs): frame allocator, heap, page tables, GDT/IDT, APIC, scheduler, IPC registry, capability system.

Work-Stealing Scheduler

Per-CPU ready queues with work-stealing enabled in the scheduler. Idle CPUs steal tasks from the busiest CPU's queue, improving multi-core utilization.

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Integration Audit Pass 2 (commit 9320ccc)

Deep exploration with 3 parallel analysis agents identified 5 remaining integration gaps.

Fix 1: Duplicate POSIX Syscall Aliases (CRITICAL)

Problem: Syscalls 300 (Poll), 301 (Fcntl), 310 (Clone), 311 (Futex) returned NotImplemented despite working implementations at other syscall numbers: FilePoll(189) -> sys_poll(), FileFcntl(158) -> sys_fcntl(), ThreadClone(46) -> sys_thread_clone(), FutexWait(201)/FutexWake(202).

Fix: Replaced NotImplemented returns with delegation to the existing handlers. Futex dispatches on arg1 (0=WAIT, 1=WAKE) to the appropriate futex operation.

Files: kernel/src/syscall/mod.rs

Fix 2: AF_INET Socket Routing (CRITICAL)

Problem: sys_socket_connect/bind/listen/accept/send/recv/close unconditionally dispatched to net::unix_socket::*, ignoring INET sockets created via net::socket::create_socket(). AF_INET sockets were created correctly but all subsequent operations went to Unix socket handlers.

Fix: Introduced INET_SOCKET_FLAG = 0x4000_0000 high-bit tagging. sys_socket_create() ORs the flag into AF_INET socket IDs. Each of the 7 socket operations checks is_inet_socket(id) and routes to net::socket::{with_socket, with_socket_mut, close_socket} with the flag stripped, or falls through to Unix socket handlers.

Files: kernel/src/syscall/mod.rs (~80 lines)

Fix 3: VirtIO PCI Probe Hooks (HIGH)

Problem: PCI enumeration (pci::init() -> enumerate_devices()) discovered VirtIO devices but never initialized their drivers. VirtIO-GPU, VirtIO-Net, and VirtIO-Sound remained dormant.

Fix: Added pci::probe_known_drivers() that iterates all discovered PCI devices and calls the appropriate driver init() for recognized VirtIO vendor/device ID pairs:

• (0x1AF4, 0x1050|0x1040) -> virtio_gpu::init()
• (0x1AF4, 0x1041|0x1000) -> virtio_net::init()
• (0x1AF4, 0x1059) -> virtio_sound::init()

Called from bootstrap.rs after PCI enumeration. Each driver's init() already handles device absence gracefully.

Files: kernel/src/drivers/pci.rs, kernel/src/bootstrap.rs, kernel/src/audio/mod.rs (visibility fix: pub(crate) mod virtio_sound)

Fix 4: Container Namespace Enforcement During Fork (MEDIUM)

Problem: fork_process() did not propagate container membership. Children of containerized processes escaped the PID namespace.

Fix: Added container_id: AtomicU64 to the Process struct (default 0 = uncontainerized). During fork, the parent's container_id is copied to the child. If non-zero, the child's PID is registered in the container's PID namespace via CONTAINER_MGR.lock() -> get_mut(cid) -> namespaces.pid.add_process(new_pid).

Files: kernel/src/process/pcb.rs, kernel/src/process/fork.rs

Fix 5: select() Syscall Implementation (MEDIUM)

Problem: sys_select() was a no-op returning Ok(0). While libc typically converts select() to poll(), kernel-side select() should work for correctness.

Fix: Replaced the stub with fd_set bitmap scanning. For each set bit in readfds/writefds, checks the process file table. Files and pipes are always ready (same simplification as sys_poll()). Returns the actual count of ready file descriptors and clears bits for non-existent fds.

Files: kernel/src/syscall/filesystem.rs

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Build Verification

Check	Result
cargo fmt --all	Clean
cargo clippy (x86_64)	0 warnings
cargo clippy (AArch64)	0 warnings
cargo clippy (RISC-V)	0 warnings
./build-kernel.sh all dev	All 3 architectures compile
x86_64 QEMU boot	29/29 tests, 2x BOOTOK
AArch64 QEMU boot	29/29 tests, 2x BOOTOK
RISC-V QEMU boot	29/29 tests, 1x BOOTOK (pre-existing re-init on 2nd cycle)

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What's NOT Changed

Item	Reason
KPTI CR3 switching	Intentionally disabled -- process page tables contain complete kernel mapping
SMP secondary CPUs	Requires APIC SIPI implementation (Phase 7.5 scope)
VirtIO GPU replacing UEFI GOP	GOP works; VirtIO GPU is Phase 7.5 enhancement
USB hardware detection	No real hardware in standard QEMU config
chown/fchown enforcement	No real UID/GID permission system yet

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Upgrade Notes

• Drop-in compatible: No API changes, no configuration changes
• Zero risk: All fixes wire existing tested code into previously-dead paths
• Recommended: All v0.10.0 users should upgrade

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Full Changelog: v0.10.0...v0.10.1