ChatGPT's diagnostic changes to address TLS_SLL_HDR_RESET issue. Current status: Partial mitigation, but root cause remains. Changes Applied: 1. SuperSlab Registry Fallback (hakmem_super_registry.h) - Added legacy table probe when hash map lookup misses - Prevents NULL returns for valid SuperSlabs during initialization - Status: ✅ Works but may hide underlying registration issues 2. TLS SLL Push Validation (tls_sll_box.h) - Reject push if SuperSlab lookup returns NULL - Reject push if class_idx mismatch detected - Added [TLS_SLL_PUSH_NO_SS] diagnostic message - Status: ✅ Prevents list corruption (defensive) 3. SuperSlab Allocation Class Fix (superslab_allocate.c) - Pass actual class_idx to sp_internal_allocate_superslab - Prevents dummy class=8 causing OOB access - Status: ✅ Root cause fix for allocation path 4. Debug Output Additions - First 256 push/pop operations traced - First 4 mismatches logged with details - SuperSlab registration state logged - Status: ✅ Diagnostic tool (not a fix) 5. TLS Hint Box Removed - Deleted ss_tls_hint_box.{c,h} (Phase 1 optimization) - Simplified to focus on stability first - Status: ⏳ Can be re-added after root cause fixed Current Problem (REMAINS UNSOLVED): - [TLS_SLL_HDR_RESET] still occurs after ~60 seconds of sh8bench - Pointer is 16 bytes offset from expected (class 1 → class 2 boundary) - hak_super_lookup returns NULL for that pointer - Suggests: Use-After-Free, Double-Free, or pointer arithmetic error Root Cause Analysis: - Pattern: Pointer offset by +16 (one class 1 stride) - Timing: Cumulative problem (appears after 60s, not immediately) - Location: Header corruption detected during TLS SLL pop Remaining Issues: ⚠️ Registry fallback is defensive (may hide registration bugs) ⚠️ Push validation prevents symptoms but not root cause ⚠️ 16-byte pointer offset source unidentified Next Steps for Investigation: 1. Full pointer arithmetic audit (Magazine ⇔ TLS SLL paths) 2. Enhanced logging at HDR_RESET point: - Expected vs actual pointer value - Pointer provenance (where it came from) - Allocation trace for that block 3. Verify Headerless flag is OFF throughout build 4. Check for double-offset application in conversions Technical Assessment: - 60% root cause fixes (allocation class, validation) - 40% defensive mitigation (registry fallback, push rejection) Performance Impact: - Registry fallback: +10-30 cycles on cold path (negligible) - Push validation: +5-10 cycles per push (acceptable) - Overall: < 2% performance impact estimated Related Issues: - Phase 1 TLS Hint Box removed temporarily - Phase 2 Headerless blocked until stability achieved 🤖 Generated with Claude Code (https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
109 lines
4.4 KiB
C++
109 lines
4.4 KiB
C++
// Phase 6-1.7: Box Theory Refactoring - Mutual exclusion check
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#if HAKMEM_TINY_PHASE6_BOX_REFACTOR
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#if defined(HAKMEM_TINY_PHASE6_METADATA) || defined(HAKMEM_TINY_PHASE6_ULTRA_SIMPLE)
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#error "Cannot enable PHASE6_BOX_REFACTOR with other Phase 6 options"
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#endif
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// Box 1: Atomic Operations (Layer 0 - Foundation)
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#include "tiny_atomic.h"
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// Box 5: Allocation Fast Path (Layer 1 - 3-4 instructions)
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#include "tiny_alloc_fast.inc.h"
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// Box 6: Free Fast Path (Layer 2 - 2-3 instructions)
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#include "tiny_free_fast.inc.h"
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// ---------------- Refill count (Front) global config ----------------
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// Parsed once at init; hot path reads plain ints (no getenv).
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int g_refill_count_global = 0; // HAKMEM_TINY_REFILL_COUNT
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int g_refill_count_hot = 0; // HAKMEM_TINY_REFILL_COUNT_HOT
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int g_refill_count_mid = 0; // HAKMEM_TINY_REFILL_COUNT_MID
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int g_refill_count_class[TINY_NUM_CLASSES] = {0}; // HAKMEM_TINY_REFILL_COUNT_C{0..7}
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// Export wrapper functions for hakmem.c to call
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// Phase 6-1.7 Optimization: Remove diagnostic overhead, rely on LTO for inlining
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void* hak_tiny_alloc_fast_wrapper(size_t size) {
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static _Atomic int g_alloc_fast_trace = 0;
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if (atomic_fetch_add_explicit(&g_alloc_fast_trace, 1, memory_order_relaxed) < 128) {
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HAK_TRACE("[tiny_alloc_fast_wrapper_enter]\n");
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}
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// Phase E5: Ultra fast path (8-instruction alloc, bypasses all layers)
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// Enable with: HAKMEM_ULTRA_FAST_PATH=1 (compile-time)
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#if HAKMEM_ULTRA_FAST_PATH
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void* ret = tiny_alloc_fast_ultra(size);
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if (ret) return ret;
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// Miss → fallback to full fast path
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#endif
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// Bench-only ultra-short path: bypass diagnostics and pointer tracking
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// Enable with: HAKMEM_BENCH_FAST_FRONT=1
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static int g_bench_fast_front = -1;
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if (__builtin_expect(g_bench_fast_front == -1, 0)) {
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const char* e = getenv("HAKMEM_BENCH_FAST_FRONT");
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g_bench_fast_front = (e && *e && *e != '0') ? 1 : 0;
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}
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if (__builtin_expect(g_bench_fast_front, 0)) {
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return tiny_alloc_fast(size);
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}
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static _Atomic uint64_t wrapper_call_count = 0;
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uint64_t call_num = atomic_fetch_add(&wrapper_call_count, 1);
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// Pointer tracking init (first call only)
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PTR_TRACK_INIT();
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// PRIORITY 3: Periodic canary validation (every 1000 ops)
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periodic_canary_check(call_num, "hak_tiny_alloc_fast_wrapper");
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// Box I: Periodic full integrity check (every 5000 ops)
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#if HAKMEM_INTEGRITY_LEVEL >= 3
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if ((call_num % 5000) == 0) {
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extern void integrity_periodic_full_check(const char*);
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integrity_periodic_full_check("periodic check in alloc wrapper");
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}
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#endif
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#if !HAKMEM_BUILD_RELEASE
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if (call_num > 14250 && call_num < 14280 && size <= 1024) {
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fprintf(stderr, "[HAK_TINY_ALLOC_FAST_WRAPPER] call=%lu size=%zu\n", call_num, size);
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fflush(stderr);
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}
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#endif
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void* result = tiny_alloc_fast(size);
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#if !HAKMEM_BUILD_RELEASE
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if (call_num > 14250 && call_num < 14280 && size <= 1024) {
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fprintf(stderr, "[HAK_TINY_ALLOC_FAST_WRAPPER] call=%lu returned %p\n", call_num, result);
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fflush(stderr);
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}
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#endif
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return result;
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}
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void hak_tiny_free_fast_wrapper(void* ptr) {
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// Phase E5: Ultra fast path (6-8 instruction free)
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#if HAKMEM_ULTRA_FAST_PATH
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tiny_free_fast_ultra(ptr);
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return;
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#endif
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static _Atomic uint64_t free_call_count = 0;
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uint64_t call_num = atomic_fetch_add(&free_call_count, 1);
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if (call_num > 14135 && call_num < 14145) {
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fprintf(stderr, "[HAK_TINY_FREE_FAST_WRAPPER] call=%lu ptr=%p\n", call_num, ptr);
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fflush(stderr);
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}
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tiny_free_fast(ptr);
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if (call_num > 14135 && call_num < 14145) {
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fprintf(stderr, "[HAK_TINY_FREE_FAST_WRAPPER] call=%lu completed\n", call_num);
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fflush(stderr);
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}
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}
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// HAKMEM_TINY_PHASE6_ULTRA_SIMPLE - REMOVED (dead code cleanup 2025-11-27)
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#elif defined(HAKMEM_TINY_PHASE6_METADATA)
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// Phase 6-1.6: Metadata header (recommended)
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#include "hakmem_tiny_metadata.inc"
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#endif
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