did we fix all the bugs yet?

tree_alloc.c

@@ -14,14 +14,15 @@ int debug_tree_black_height(TreeAlloc *node) {
 	return ((node->color == COLOR_BLACK) ? 1 : 0) + debug_tree_black_height(node->left);
 }
 
-void debug_print_tree(int indent, void *p) {
+void debug_print_tree(int indent, void *p, int safe) {
 	TreeAlloc *node = (TreeAlloc*) p;
 	if (node != NULL) {
 		int bad = debug_tree_black_height(node->left) != debug_tree_black_height(node->right);
 		bad |= node->color == COLOR_RED && ((node->left != NULL && node->left->color == COLOR_RED) ||
 				(node->right != NULL && node->right->color == COLOR_RED) || (node->parent != NULL &&
 					node->parent->color == COLOR_RED));
-		debug_print_tree(indent + 1, node->left);
+    bad &= !safe;
+		debug_print_tree(indent + 1, node->left, safe);
 		for (int ii = 0; ii < indent; ii++) { printf("  "); }
 		if (node->color == COLOR_RED) { printf("\e[31m"); }
     else if (bad) { printf("\e[30m]"); }
@@ -29,7 +30,7 @@ void debug_print_tree(int indent, void *p) {
 		printf("%p %lu\n", node, node->size);
 		printf("\e[37m");
 		if (bad) { printf("\e[40m"); }
-		debug_print_tree(indent + 1, node->right);
+		debug_print_tree(indent + 1, node->right, safe);
 	}
 }
 
@@ -230,7 +231,7 @@ void insert_singleton(TreeAlloc **root_ptr, TreeAlloc *to_insert) {
 #ifdef DEBUG
 	printf("= PRE-INSERT-SINGLETON =\n");
 	printf("===== CURRENT TREE =====\n");
-	debug_print_tree(0, *root_ptr);
+	debug_print_tree(0, *root_ptr, 0);
 	printf("===== END OF TREES =====\n");
 #endif
 	*root_ptr = to_insert;
@@ -239,7 +240,7 @@ void insert_singleton(TreeAlloc **root_ptr, TreeAlloc *to_insert) {
 #ifdef DEBUG
 	printf("= POST-INSERT-SINGLETON =\n");
 	printf("===== CURRENT TREE =====\n");
-	debug_print_tree(0, *root_ptr);
+	debug_print_tree(0, *root_ptr, 0);
 	printf("===== END OF TREES =====\n");
 #endif
 }
@@ -248,9 +249,9 @@ void insert_right(TreeAlloc** root_ptr, TreeAlloc* to_insert, TreeAlloc* after)
 #ifdef DEBUG
 	printf("=== PRE-INSERT-RIGHT ===\n");
 	printf("===== INSERTING =====\n");
-	debug_print_tree(0, to_insert);
+	debug_print_tree(0, to_insert, 0);
 	printf("===== CURRENT TREE =====\n");
-	debug_print_tree(0, *root_ptr);
+	debug_print_tree(0, *root_ptr, 0);
 	printf("===== END OF TREES =====\n");
 #endif
   if (after->right != NULL) {
@@ -269,7 +270,7 @@ void insert_right(TreeAlloc** root_ptr, TreeAlloc* to_insert, TreeAlloc* after)
 #ifdef DEBUG
 	printf("== POST-INSERT-FIXUP ===\n");
 	printf("===== CURRENT TREE =====\n");
-	debug_print_tree(0, *root_ptr);
+	debug_print_tree(0, *root_ptr, 0);
 	printf("===== END OF TREES =====\n");
 #endif
 }
@@ -278,9 +279,9 @@ void insert_left(TreeAlloc** root_ptr, TreeAlloc* to_insert, TreeAlloc* before)
 #ifdef DEBUG
 	printf("=== PRE-INSERT-LEFT ====\n");
 	printf("===== INSERTING =====\n");
-	debug_print_tree(0, to_insert);
+	debug_print_tree(0, to_insert, 0);
 	printf("===== CURRENT TREE =====\n");
-	debug_print_tree(0, *root_ptr);
+	debug_print_tree(0, *root_ptr, 0);
 	printf("===== END OF TREES =====\n");
 #endif
   if (before->left != NULL) {
@@ -299,7 +300,7 @@ void insert_left(TreeAlloc** root_ptr, TreeAlloc* to_insert, TreeAlloc* before)
 #ifdef DEBUG
 	printf("== POST-INSERT-FIXUP ===\n");
 	printf("===== CURRENT TREE =====\n");
-	debug_print_tree(0, *root_ptr);
+	debug_print_tree(0, *root_ptr, 0);
 	printf("===== END OF TREES =====\n");
 #endif
 }
@@ -318,7 +319,7 @@ void replace_node(TreeAlloc **root_ptr, TreeAlloc *node, TreeAlloc *replace) {
 
 void repair_after_remove(TreeAlloc **root_ptr, TreeAlloc *parent, TreeAlloc *node) {
 #ifdef DEBUG
-  printf("delete fixup at %p\n", node);
+  printf("delete fixup at %p -> %p\n", parent, node);
 #endif
   // In theory, the last two conditions should be the same ...
 	if (IS_RED_NODE(node) || (node != NULL && node == *root_ptr)) {
@@ -326,7 +327,7 @@ void repair_after_remove(TreeAlloc **root_ptr, TreeAlloc *parent, TreeAlloc *nod
 	} else {
 		TreeAlloc *sibling = get_sibling(parent, node);
 		if (IS_RED_NODE(sibling)) {
-			if (node->parent->left == node) {
+			if (parent->left == node) {
 				rotate_left(root_ptr, parent);
 			} else {
 				rotate_right(root_ptr, parent);
@@ -377,34 +378,45 @@ void remove_node(TreeAlloc **root_ptr, TreeAlloc *to_remove) {
   char old_color;
 #ifdef DEBUG
 	printf("====== PRE-REMOVE ======\n");
-	printf("===== REMOVING =====\n");
-	debug_print_tree(0, to_remove);
+	printf("======= REMOVING =======\n");
+	debug_print_tree(0, to_remove, 0);
 	printf("===== CURRENT TREE =====\n");
-	debug_print_tree(0, *root_ptr);
+	debug_print_tree(0, *root_ptr, 0);
 	printf("===== END OF TREES =====\n");
 #endif
 	TreeAlloc *replace, *parent_of_replace;
 	TreeAlloc *parent = to_remove->parent;
 	if (!to_remove->left) {
+#ifdef DEBUG
+    printf("code path 1l\n");
+#endif
 		replace = to_remove->right;
     parent_of_replace = to_remove->parent;
 		do_repair = to_remove->color == COLOR_BLACK;
 		replace_node(root_ptr, to_remove, replace);
 	} else if (!to_remove->right) {
+#ifdef DEBUG
+    printf("code path 1r\n");
+#endif
 		replace = to_remove->left;
     parent_of_replace = to_remove->parent;
 		do_repair = to_remove->color == COLOR_BLACK;
 		replace_node(root_ptr, to_remove, replace);
 	} else {
+#ifdef DEBUG
+    printf("code path 2\n");
+#endif
 		TreeAlloc *tmp = succ(to_remove);
 		replace = tmp->right;
-    parent_of_replace = tmp->parent;
 		do_repair = tmp->color == COLOR_BLACK;
 		if (tmp != to_remove->right) {
 			replace_node(root_ptr, tmp, replace);
 			tmp->right = to_remove->right;
 			to_remove->right->parent = tmp;
-		}
+      parent_of_replace = tmp->parent;
+		} else {
+      parent_of_replace = tmp;
+    }
 		replace_node(root_ptr, to_remove, tmp);
 		tmp->color = to_remove->color;
 		tmp->left = to_remove->left;
@@ -414,6 +426,13 @@ void remove_node(TreeAlloc **root_ptr, TreeAlloc *to_remove) {
 	// Make sure that it doesn't have any tree pointers it shouldn't have.
 	to_remove->parent = to_remove->left = to_remove->right = NULL;
 
+#ifdef DEBUG
+	printf("==== PRE-REMOVE-FIXUP ===\n");
+	printf("===== CURRENT TREE =====\n");
+	debug_print_tree(0, *root_ptr, 1);
+	printf("===== END OF TREES =====\n");
+  printf("considering fixing up %p -> %p\n", parent_of_replace, replace);
+#endif
 	if (replace && parent_of_replace == NULL) {
 		replace->color = COLOR_BLACK;
 	} else if (parent_of_replace != NULL && do_repair) {
@@ -422,7 +441,7 @@ void remove_node(TreeAlloc **root_ptr, TreeAlloc *to_remove) {
 #ifdef DEBUG
 	printf("=== POST-REMOVE ===\n");
 	printf("===== CURRENT TREE =====\n");
-	debug_print_tree(0, *root_ptr);
+	debug_print_tree(0, *root_ptr, 0);
 	printf("===== END OF TREES =====\n");
 #endif
 }
@@ -455,9 +474,9 @@ int add_new_region(Arena *arena, uintptr_t size, uintptr_t padding, uintptr_t al
 #ifdef DEBUG
 	printf("= POST-REGION-CREATION =\n");
 	printf("==== FREESPACE TREE ====\n");
-	debug_print_tree(0, arena->root_freespace);
+	debug_print_tree(0, arena->root_freespace, 0);
 	printf("==== TREEALLOC TREE ====\n");
-	debug_print_tree(0, arena->root_treealloc);
+	debug_print_tree(0, arena->root_treealloc, 0);
 	printf("===== END OF TREES =====\n");
 #endif
 	return 1;
@@ -467,9 +486,9 @@ void unalloc(Arena *arena, void *addr) {
 #ifdef DEBUG
 	printf("==== UNALLOCATING ====\n");
 	printf("=== FREESPACE TREE ===\n");
-	debug_print_tree(0, arena->root_freespace);
+	debug_print_tree(0, arena->root_freespace, 0);
 	printf("=== TREEALLOC TREE ===\n");
-	debug_print_tree(0, arena->root_treealloc);
+	debug_print_tree(0, arena->root_treealloc, 0);
 	printf("==== END OF TREES ====\n");
 #endif
 	if (arena->root_treealloc == NULL) {
@@ -526,9 +545,9 @@ void *alloc(Arena *arena, uintptr_t size, uintptr_t align) {
 #ifdef DEBUG
 	printf("==== ALLOCATING =====\n");
 	printf("=== FREESPACE TREE ===\n");
-	debug_print_tree(0, arena->root_freespace);
+	debug_print_tree(0, arena->root_freespace, 0);
 	printf("=== TREEALLOC TREE ===\n");
-	debug_print_tree(0, arena->root_treealloc);
+	debug_print_tree(0, arena->root_treealloc, 0);
 	printf("==== END OF TREES ====\n");
 #endif
 	if (arena->root_freespace == NULL) {