diff --git a/.gitignore b/.gitignore
index 9c3f938..f24776a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,3 +9,5 @@ docs/
 examples/
 internal_docs
 build.sh
+libctru/source/util/rbtree/test/*.o
+libctru/source/util/rbtree/test/rbtree_test
diff --git a/libctru/source/allocator/linear.cpp b/libctru/source/allocator/linear.cpp
index 8d8182a..8818817 100644
--- a/libctru/source/allocator/linear.cpp
+++ b/libctru/source/allocator/linear.cpp
@@ -7,11 +7,13 @@ extern "C"
 
 #include "mem_pool.h"
 #include "addrmap.h"
+#include "lock.h"
 
 extern u32 __ctru_linear_heap;
 extern u32 __ctru_linear_heap_size;
 
 static MemPool sLinearPool;
+static LightLock sLock = 1;
 
 static bool linearInit()
 {
@@ -42,6 +44,7 @@ void* linearMemAlign(size_t size, size_t alignment)
 		return nullptr;
 
 	// Initialize the pool if it is not ready
+	LockGuard guard(sLock);
 	if (!sLinearPool.Ready() && !linearInit())
 		return nullptr;
 
@@ -73,12 +76,14 @@ void* linearRealloc(void* mem, size_t size)
 
 size_t linearGetSize(void* mem)
 {
+	LockGuard guard(sLock);
 	auto node = getNode(mem);
 	return node ? node->chunk.size : 0;
 }
 
 void linearFree(void* mem)
 {
+	LockGuard guard(sLock);
 	auto node = getNode(mem);
 	if (!node) return;
 
@@ -91,5 +96,6 @@ void linearFree(void* mem)
 
 u32 linearSpaceFree()
 {
+	LockGuard guard(sLock);
 	return sLinearPool.GetFreeSpace();
 }
diff --git a/libctru/source/allocator/lock.h b/libctru/source/allocator/lock.h
new file mode 100644
index 0000000..66fefd7
--- /dev/null
+++ b/libctru/source/allocator/lock.h
@@ -0,0 +1,23 @@
+#pragma once
+
+extern "C"
+{
+	#include <3ds/synchronization.h>
+}
+
+class LockGuard
+{
+public:
+	~LockGuard()
+	{
+		LightLock_Unlock(&lock);
+	}
+
+	LockGuard(LightLock &lock) : lock(lock)
+	{
+		LightLock_Lock(&lock);
+	}
+
+private:
+	LightLock &lock;
+};
diff --git a/libctru/source/allocator/mappable.cpp b/libctru/source/allocator/mappable.cpp
index c75d7cd..1c2371c 100644
--- a/libctru/source/allocator/mappable.cpp
+++ b/libctru/source/allocator/mappable.cpp
@@ -7,8 +7,10 @@ extern "C"
 
 #include "mem_pool.h"
 #include "addrmap.h"
+#include "lock.h"
 
 static MemPool sMappablePool;
+static LightLock sLock = 1;
 
 static bool mappableInit()
 {
@@ -25,6 +27,7 @@ static bool mappableInit()
 void* mappableAlloc(size_t size)
 {
 	// Initialize the pool if it is not ready
+	LockGuard guard(sLock);
 	if (!sMappablePool.Ready() && !mappableInit())
 		return nullptr;
 
@@ -45,12 +48,14 @@ void* mappableAlloc(size_t size)
 
 size_t mappableGetSize(void* mem)
 {
+	LockGuard guard(sLock);
 	auto node = getNode(mem);
 	return node ? node->chunk.size : 0;
 }
 
 void mappableFree(void* mem)
 {
+	LockGuard guard(sLock);
 	auto node = getNode(mem);
 	if (!node) return;
 
@@ -63,5 +68,6 @@ void mappableFree(void* mem)
 
 u32 mappableSpaceFree()
 {
+	LockGuard guard(sLock);
 	return sMappablePool.GetFreeSpace();
 }
diff --git a/libctru/source/allocator/vram.cpp b/libctru/source/allocator/vram.cpp
index 30498a5..8f23417 100644
--- a/libctru/source/allocator/vram.cpp
+++ b/libctru/source/allocator/vram.cpp
@@ -7,8 +7,10 @@ extern "C"
 
 #include "mem_pool.h"
 #include "addrmap.h"
+#include "lock.h"
 
 static MemPool sVramPool;
+static LightLock sLock = 1;
 
 static bool vramInit()
 {
@@ -39,6 +41,7 @@ void* vramMemAlign(size_t size, size_t alignment)
 		return nullptr;
 
 	// Initialize the pool if it is not ready
+	LockGuard guard(sLock);
 	if (!sVramPool.Ready() && !vramInit())
 		return nullptr;
 
@@ -70,12 +73,14 @@ void* vramRealloc(void* mem, size_t size)
 
 size_t vramGetSize(void* mem)
 {
+	LockGuard guard(sLock);
 	auto node = getNode(mem);
 	return node ? node->chunk.size : 0;
 }
 
 void vramFree(void* mem)
 {
+	LockGuard guard(sLock);
 	auto node = getNode(mem);
 	if (!node) return;
 
@@ -88,5 +93,6 @@ void vramFree(void* mem)
 
 u32 vramSpaceFree()
 {
+	LockGuard guard(sLock);
 	return sVramPool.GetFreeSpace();
 }
diff --git a/libctru/source/util/rbtree/rbtree_clear.c b/libctru/source/util/rbtree/rbtree_clear.c
index fd945f1..fe5c803 100644
--- a/libctru/source/util/rbtree/rbtree_clear.c
+++ b/libctru/source/util/rbtree/rbtree_clear.c
@@ -5,6 +5,8 @@ void
 rbtree_clear(rbtree_t                 *tree,
              rbtree_node_destructor_t destructor)
 {
+  rbtree_validate(tree);
+
   rbtree_node_t *node = tree->root;
 
   while(tree->root != NULL)
@@ -31,4 +33,6 @@ rbtree_clear(rbtree_t                 *tree,
   }
 
   tree->size = 0;
+
+  rbtree_validate(tree);
 }
diff --git a/libctru/source/util/rbtree/rbtree_empty.c b/libctru/source/util/rbtree/rbtree_empty.c
index 5ccdfff..c47170d 100644
--- a/libctru/source/util/rbtree/rbtree_empty.c
+++ b/libctru/source/util/rbtree/rbtree_empty.c
@@ -1,7 +1,10 @@
 #include <3ds/util/rbtree.h>
+#include "rbtree_internal.h"
 
 int
 rbtree_empty(const rbtree_t *tree)
 {
+  rbtree_validate(tree);
+
   return tree->root == NULL;
 }
diff --git a/libctru/source/util/rbtree/rbtree_find.c b/libctru/source/util/rbtree/rbtree_find.c
index 3b5ff99..19c9f27 100644
--- a/libctru/source/util/rbtree/rbtree_find.c
+++ b/libctru/source/util/rbtree/rbtree_find.c
@@ -5,6 +5,8 @@ rbtree_node_t*
 rbtree_find(const rbtree_t      *tree,
             const rbtree_node_t *node)
 {
+  rbtree_validate(tree);
+
   rbtree_node_t *tmp  = tree->root;
   rbtree_node_t *save = NULL;
 
@@ -26,5 +28,7 @@ rbtree_find(const rbtree_t      *tree,
     }
   }
 
+  rbtree_validate(tree);
+
   return save;
 }
diff --git a/libctru/source/util/rbtree/rbtree_init.c b/libctru/source/util/rbtree/rbtree_init.c
index a8c30d5..b1a826c 100644
--- a/libctru/source/util/rbtree/rbtree_init.c
+++ b/libctru/source/util/rbtree/rbtree_init.c
@@ -1,4 +1,5 @@
 #include <3ds/util/rbtree.h>
+#include "rbtree_internal.h"
 
 void
 rbtree_init(rbtree_t                 *tree,
@@ -7,4 +8,6 @@ rbtree_init(rbtree_t                 *tree,
   tree->root       = NULL;
   tree->comparator = comparator;
   tree->size       = 0;
+
+  rbtree_validate(tree);
 }
diff --git a/libctru/source/util/rbtree/rbtree_insert.c b/libctru/source/util/rbtree/rbtree_insert.c
index 29950ec..536b9d2 100644
--- a/libctru/source/util/rbtree/rbtree_insert.c
+++ b/libctru/source/util/rbtree/rbtree_insert.c
@@ -6,6 +6,8 @@ do_insert(rbtree_t      *tree,
           rbtree_node_t *node,
           int           multi)
 {
+  rbtree_validate(tree);
+
   rbtree_node_t *original = node;
   rbtree_node_t **tmp     = &tree->root;
   rbtree_node_t *parent   = NULL;
@@ -31,6 +33,8 @@ do_insert(rbtree_t      *tree,
 
   if(save != NULL)
   {
+    rbtree_validate(tree);
+
     return save;
   }
 
@@ -78,6 +82,8 @@ do_insert(rbtree_t      *tree,
 
   tree->size += 1;
 
+  rbtree_validate(tree);
+
   return original;
 }
 
diff --git a/libctru/source/util/rbtree/rbtree_internal.h b/libctru/source/util/rbtree/rbtree_internal.h
index 6d0d0a9..8719afe 100644
--- a/libctru/source/util/rbtree/rbtree_internal.h
+++ b/libctru/source/util/rbtree/rbtree_internal.h
@@ -1,4 +1,5 @@
 #pragma once
+#include "3ds/util/rbtree.h"
 
 #define LEFT  0
 #define RIGHT 1
@@ -62,3 +63,9 @@ void
 rbtree_rotate(rbtree_t      *tree,
               rbtree_node_t *node,
               int           left);
+
+void
+rbtree_validate(const rbtree_t *tree);
+
+void
+rbtree_node_validate(const rbtree_t *tree, const rbtree_node_t *node, size_t *all, size_t *black, size_t *depth);
diff --git a/libctru/source/util/rbtree/rbtree_minmax.c b/libctru/source/util/rbtree/rbtree_minmax.c
index f74293c..54c9cf4 100644
--- a/libctru/source/util/rbtree/rbtree_minmax.c
+++ b/libctru/source/util/rbtree/rbtree_minmax.c
@@ -5,6 +5,8 @@ static inline rbtree_node_t*
 do_minmax(const rbtree_t *tree,
           int            max)
 {
+  rbtree_validate(tree);
+
   rbtree_node_t *node = tree->root;
 
   if(node == NULL)
diff --git a/libctru/source/util/rbtree/rbtree_remove.c b/libctru/source/util/rbtree/rbtree_remove.c
index 8a0359a..412474c 100644
--- a/libctru/source/util/rbtree/rbtree_remove.c
+++ b/libctru/source/util/rbtree/rbtree_remove.c
@@ -60,6 +60,8 @@ rbtree_remove(rbtree_t                 *tree,
               rbtree_node_t            *node,
               rbtree_node_destructor_t destructor)
 {
+  rbtree_validate(tree);
+
   rbtree_color_t color;
   rbtree_node_t  *child, *parent, *original = node;
   rbtree_node_t  *next;
@@ -136,5 +138,7 @@ rbtree_remove(rbtree_t                 *tree,
 
   tree->size -= 1;
 
+  rbtree_validate(tree);
+
   return next;
 }
diff --git a/libctru/source/util/rbtree/rbtree_size.c b/libctru/source/util/rbtree/rbtree_size.c
index 401d43d..e596366 100644
--- a/libctru/source/util/rbtree/rbtree_size.c
+++ b/libctru/source/util/rbtree/rbtree_size.c
@@ -1,7 +1,10 @@
 #include <3ds/util/rbtree.h>
+#include "rbtree_internal.h"
 
 size_t
 rbtree_size(const rbtree_t *tree)
 {
+  rbtree_validate(tree);
+
   return tree->size;
 }
diff --git a/libctru/source/util/rbtree/rbtree_validate.c b/libctru/source/util/rbtree/rbtree_validate.c
new file mode 100644
index 0000000..431635e
--- /dev/null
+++ b/libctru/source/util/rbtree/rbtree_validate.c
@@ -0,0 +1,136 @@
+#include "rbtree_internal.h"
+
+#include <3ds/svc.h>
+
+#include <stdlib.h>
+
+#define panic() do { \
+  svcBreak(USERBREAK_PANIC); \
+  abort(); \
+} while(0)
+
+
+void
+rbtree_validate(const rbtree_t *tree)
+{
+  if(!tree)
+    panic();
+
+  // root node must be black
+  if(!is_black(tree->root))
+    panic();
+
+  // root node's parent must be null
+  if(tree->root)
+  {
+    if(get_parent(tree->root) != NULL)
+      panic();
+  }
+
+  // validate subtree starting at root node
+  size_t size = 0;
+  rbtree_node_validate(tree, tree->root, &size, NULL, NULL);
+
+  // make sure we are tracking the correct number of nodes
+  if(size != tree->size)
+    panic();
+}
+
+void
+rbtree_node_validate(const rbtree_t *tree, const rbtree_node_t *node, size_t *size, size_t *black, size_t *depth)
+{
+  if(!node) // implies is_black
+  {
+    if(black)
+      *black += 1;
+
+    if(depth)
+      *depth = 1;
+
+    return;
+  }
+  else // non-null
+  {
+    rbtree_node_t *parent = get_parent(node);
+    if(!parent)
+    {
+      // only the root node can have a null parent
+      if(node != tree->root)
+        panic();
+    }
+    else
+    {
+      // make sure this node is a child of its parent
+      if(parent->child[LEFT] != node && parent->child[RIGHT] != node)
+        panic();
+
+      // if the parent is red, this node must be black
+      if(is_red(parent) && !is_black(node))
+        panic();
+    }
+  }
+
+  if(is_red(node))
+  {
+    // if this node is red, both children must be black
+    if(!is_black(node->child[LEFT]))
+      panic();
+
+    if(!is_black(node->child[RIGHT]))
+      panic();
+  }
+
+  if(node->child[LEFT])
+  {
+    // this node must be >= left child
+    if((*(tree->comparator))(node, node->child[LEFT]) < 0)
+      panic();
+  }
+
+  if(node->child[RIGHT])
+  {
+    // this node must be <= right child
+    if((*(tree->comparator))(node, node->child[RIGHT]) > 0)
+      panic();
+  }
+
+  // validate subtree at left child
+  size_t left_size = 0;
+  size_t left_black = 0;
+  size_t left_depth = 0;
+  rbtree_node_validate(tree, node->child[LEFT], &left_size, &left_black, &left_depth);
+
+  // validate subtree at right child
+  size_t right_size = 0;
+  size_t right_black = 0;
+  size_t right_depth = 0;
+  rbtree_node_validate(tree, node->child[RIGHT], &right_size, &right_black, &right_depth);
+
+  // size is left+right subtrees plus self
+  if(size)
+    *size += left_size + right_size + 1;
+
+  // all possible paths to leaf nodes must have the same number of black nodes along the path
+  if(left_black != right_black)
+    panic();
+
+  if(black)
+    *black += left_black + (is_black(node) ? 1 : 0);
+
+  // depth of one subtree must not exceed 2x depth of the other subtree
+  if(left_depth < right_depth)
+  {
+    if(right_depth - left_depth > left_depth)
+      panic();
+  }
+  else if(left_depth - right_depth > right_depth)
+    panic();
+
+  if(depth)
+  {
+    if(left_depth > right_depth)
+      *depth = left_depth + 1;
+    else
+      *depth = right_depth + 1;
+  }
+}
diff --git a/libctru/source/util/rbtree/test/Makefile b/libctru/source/util/rbtree/test/Makefile
new file mode 100644
index 0000000..87835e0
--- /dev/null
+++ b/libctru/source/util/rbtree/test/Makefile
@@ -0,0 +1,23 @@
+CFILES   := $(wildcard ../*.c)
+CXXFILES := $(wildcard *.cpp)
+
+OFILES   := $(patsubst ../%,%,$(CFILES:.c=.c.o))
+OXXFILES := $(CXXFILES:.cpp=.cpp.o)
+
+CPPFLAGS := -Wall -g -I../../../../include -O2
+CFLAGS   := $(CPPFLAGS)
+CXXFLAGS := $(CPPFLAGS) -std=c++11
+
+all: rbtree_test
+
+rbtree_test: $(OFILES) $(OXXFILES)
+	$(CXX) -o $@ $^ $(LDFLAGS)
+
+$(OFILES): %.c.o: ../%.c
+	$(CC) -o $@ -c $< $(CFLAGS)
+
+$(OXXFILES): %.cpp.o: %.cpp
+	$(CXX) -o $@ -c $< $(CXXFLAGS)
+
+clean:
+	$(RM) rbtree_test $(OFILES) $(OXXFILES)
diff --git a/libctru/source/util/rbtree/test/main.cpp b/libctru/source/util/rbtree/test/main.cpp
new file mode 100644
index 0000000..3799e1b
--- /dev/null
+++ b/libctru/source/util/rbtree/test/main.cpp
@@ -0,0 +1,126 @@
+extern "C"
+{
+#include <3ds/svc.h>
+#include <3ds/util/rbtree.h>
+#include "../rbtree_internal.h"
+}
+
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+#include <functional>
+#include <limits>
+#include <random>
+#include <vector>
+
+namespace
+{
+struct IntNode
+{
+  IntNode(int value) : value(value)
+  {}
+
+  const int value;
+  rbtree_node_t node;
+};
+
+IntNode *getIntNode(rbtree_node_t *node)
+{
+  return rbtree_item(node, IntNode, node);
+}
+
+const IntNode *getIntNode(const rbtree_node_t *node)
+{
+  return rbtree_item(node, IntNode, node);
+}
+
+void IntNodeDestructor(rbtree_node_t *node)
+{
+  delete getIntNode(node);
+}
+
+int IntNodeComparator(const rbtree_node_t *lhs, const rbtree_node_t *rhs)
+{
+  auto left = getIntNode(lhs)->value;
+  auto right = getIntNode(rhs)->value;
+
+  if(left < right)
+    return -1;
+  if(right < left)
+    return 1;
+  return 0;
+}
+
+#if 0
+void printNode(const rbtree_node_t *node, int indent)
+{
+  if(!node)
+  {
+    std::printf("%*s(nil) black\n", indent, "");
+    return;
+  }
+
+  std::printf("%*s%d %s\n", indent, "", getIntNode(node)->value, is_black(node) ? "black" : "red");
+
+  printNode(node->child[LEFT], indent + 2);
+  printNode(node->child[RIGHT], indent + 2);
+}
+
+void printTree(const rbtree_t *tree)
+{
+  std::printf("==========\n");
+  printNode(tree->root, 0);
+}
+#endif
+}
+
+void svcBreak(UserBreakType breakReason)
+{
+}
+
+int main(int argc, char *argv[])
+{
+  std::default_random_engine eng;
+
+  {
+    std::random_device rand;
+    std::random_device::result_type seedBuffer[32];
+    for(auto &d : seedBuffer)
+      d = rand();
+
+    std::seed_seq seed(std::begin(seedBuffer), std::end(seedBuffer));
+    eng.seed(seed);
+  }
+
+  auto dist = std::bind(std::uniform_int_distribution<int>(std::numeric_limits<int>::min(), std::numeric_limits<int>::max()), std::ref(eng));
+  auto remove = std::bind(std::uniform_int_distribution<std::size_t>(0, 100), std::ref(eng));
+
+  rbtree_t tree;
+  rbtree_init(&tree, IntNodeComparator);
+
+  for(std::size_t chance = 0; chance <= 100; chance += 25)
+  {
+    std::printf("Chance %zu\n", chance);
+
+    std::vector<IntNode*> nodes;
+    for(std::size_t i = 0; i < 10000; ++i)
+    {
+      auto node = new IntNode(dist());
+      if(rbtree_insert(&tree, &node->node) != &node->node)
+        delete node;
+      else
+        nodes.emplace_back(node);
+
+      if(remove() < chance)
+      {
+        auto it = std::begin(nodes) + (eng() % nodes.size());
+        rbtree_remove(&tree, &(*it)->node, IntNodeDestructor);
+        nodes.erase(it);
+      }
+
+//      printTree(&tree);
+    }
+  }
+
+  rbtree_clear(&tree, IntNodeDestructor);
+}