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3a2e466af1
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Add lightweight Fail-Fast layer to Gatekeeper Boxes
Core Changes:
- Modified: core/box/tiny_free_gate_box.h
* Added address range check in tiny_free_gate_try_fast() (line 142)
* Catches obviously invalid pointers (addr < 4096)
* Rejects fast path for garbage pointers, delegates to slow path
* Logs [TINY_FREE_GATE_RANGE_INVALID] (debug-only, max 8 messages)
* Cost: ~1 cycle (comparison + unlikely branch)
* Behavior: Fails safe by delegating to hak_tiny_free() slow path
- Modified: core/box/tiny_alloc_gate_box.h
* Added range check for malloc_tiny_fast() return value (line 143)
* Debug-only: Checks if returned user_ptr has addr < 4096
* On failure: Logs [TINY_ALLOC_GATE_RANGE_INVALID] and calls abort()
* Release build: Entire check compiled out (zero overhead)
* Rationale: Invalid allocator return is catastrophic - fail immediately
Design Rationale:
- Early detection of memory corruption/undefined behavior
- Conservative threshold (4096) captures NULL and kernel space
- Free path: Graceful degradation (delegate to slow path)
- Alloc path: Hard fail (allocator corruption is non-recoverable)
- Zero performance impact in production (Release) builds
- Debug-only diagnostic output prevents log spam
Fail-Fast Strategy:
- Layer 3a: Address range sanity check (always enabled)
* Rejects addr < 4096 (NULL, low memory garbage)
* Free: delegates to slow path (safe fallback)
* Alloc: aborts (corruption indicator)
- Layer 3b: Detailed Bridge/Header validation (ENV-controlled)
* Traditional HAKMEM_TINY_FREE_GATE_DIAG / HAKMEM_TINY_ALLOC_GATE_DIAG
* For advanced debugging and observability
Testing:
- Compilation: RELEASE=0 and RELEASE=1 both successful
- Smoke tests: 3/3 passed (simple_alloc, loop 10M, pool_tls)
- Performance: No regressions detected
- Address threshold (4096): Conservative, minimizes false positives
- Verified via Task agent (PASS verdict)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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2025-12-04 12:36:32 +09:00 |
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291c84a1a7
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Add Tiny Alloc Gatekeeper Box for unified malloc entry point
Core Changes:
- New file: core/box/tiny_alloc_gate_box.h
* Thin wrapper around malloc_tiny_fast() with diagnostic hooks
* TinyAllocGateContext structure for size/class_idx/user/base/bridge information
* tiny_alloc_gate_diag_enabled() - ENV-controlled diagnostic mode
* tiny_alloc_gate_validate() - Validates class_idx/header/meta consistency
* tiny_alloc_gate_fast() - Main gatekeeper function
* Zero performance impact when diagnostics disabled
- Modified: core/box/hak_wrappers.inc.h
* Added #include "tiny_alloc_gate_box.h" (line 35)
* Integrated gatekeeper into malloc wrapper (lines 198-200)
* Diagnostic mode via HAKMEM_TINY_ALLOC_GATE_DIAG env var
Design Rationale:
- Complements Free Gatekeeper Box: Together they provide entry/exit hooks
- Validates allocation consistency at malloc time
- Enables Bridge + BASE/USER conversion validation in debug mode
- Maintains backward compatibility: existing behavior unchanged
Validation Features:
- tiny_ptr_bridge_classify_raw() - Verifies Superslab/Slab/meta lookup
- Header vs meta class consistency check (rate-limited, 8 msgs max)
- class_idx validation via hak_tiny_size_to_class()
- All validation logged but non-blocking (observation points for Guard)
Testing:
- All smoke tests pass (10M malloc/free cycles, pool TLS, real programs)
- Diagnostic mode validated with HAKMEM_TINY_ALLOC_GATE_DIAG=1
- No regressions in existing functionality
- Verified via Task agent (PASS verdict)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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2025-12-04 12:06:14 +09:00 |
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