new way to track actor bad memory access

source/buddy_debug.c

@@ -0,0 +1,66 @@
+/* buddy_debug.c — ASCII visualization for buddy allocator
+   Included from runtime.c only when DUMP_BUDDY is defined. */
+
+static void buddy_dump(BuddyPool *pool, const char *op,
+                       uint8_t *block, uint8_t order) {
+  if (!pool || !pool->base) return;
+
+  int levels = pool->max_order - BUDDY_MIN_ORDER + 1;
+
+  /* Bitmap: one byte per min-block slot */
+  size_t num_slots = pool->total_size >> BUDDY_MIN_ORDER;
+  /* Dynamic VLA — pool sizes vary now */
+  uint8_t *bitmap = alloca(num_slots);
+  memset(bitmap, 0, num_slots); /* 0 = allocated */
+
+  /* Walk all free lists and mark free slots */
+  for (int i = 0; i < levels; i++) {
+    for (BuddyBlock *p = pool->free_lists[i]; p; p = p->next) {
+      size_t off = (uint8_t *)p - pool->base;
+      size_t slot = off >> BUDDY_MIN_ORDER;
+      size_t count = 1ULL << i; /* number of min-block slots in this block */
+      for (size_t s = 0; s < count && (slot + s) < num_slots; s++)
+        bitmap[slot + s] = 1;
+    }
+  }
+
+  /* Render 64-char ASCII bar */
+  size_t slots_per_char = num_slots / 64;
+  if (slots_per_char == 0) slots_per_char = 1;
+  char bar[65];
+  size_t total_free_slots = 0;
+  for (int c = 0; c < 64; c++) {
+    size_t base_slot = c * slots_per_char;
+    size_t free_count = 0;
+    for (size_t s = 0; s < slots_per_char && (base_slot + s) < num_slots; s++) {
+      if (bitmap[base_slot + s]) free_count++;
+    }
+    total_free_slots += free_count;
+    /* Majority vote: if more than half are free, show free */
+    bar[c] = (free_count > slots_per_char / 2) ? '.' : '#';
+  }
+  bar[64] = '\0';
+
+  size_t blk_offset = block - pool->base;
+  size_t blk_size = 1ULL << order;
+  size_t total_free = total_free_slots << BUDDY_MIN_ORDER;
+  size_t total_alloc = pool->total_size - total_free;
+
+  fprintf(stderr, "buddy %s: pool %zuKB order %u (%zuKB) @ +%zuKB allocs=%u\n",
+          op, pool->total_size / 1024, order, blk_size / 1024,
+          blk_offset / 1024, pool->alloc_count);
+  fprintf(stderr, "  [%s]\n", bar);
+  fprintf(stderr, "  alloc: %zuKB  free: %zuKB  total: %zuKB\n",
+          total_alloc / 1024, total_free / 1024, pool->total_size / 1024);
+
+  /* Print free list population */
+  fprintf(stderr, "  free lists:");
+  for (int i = 0; i < levels; i++) {
+    int count = 0;
+    for (BuddyBlock *p = pool->free_lists[i]; p; p = p->next)
+      count++;
+    if (count > 0)
+      fprintf(stderr, " o%d:%d", i + BUDDY_MIN_ORDER, count);
+  }
+  fprintf(stderr, "\n");
+}