[scudo][standalone] Introduce platform specific code & mutexes

Summary:
This CL adds the platform specific code for Fuchsia, Linux & Android,
as well as some tests related to those (more tests to come later).
While some of it is pretty much a straight port of the existing scudo &
sanitizer_common code, the memory mapping functions have been reworked
a bit to fit the limited usage scenario that Scudo has for them.

For Fuchsia, I can now track the Vmar/Vmo pair for memory mappings if
there is an intent to grow or decommit some mapping (that will be
useful for the Primary).

Reviewers: eugenis, vitalybuka, mcgrathr, phosek, flowerhack, morehouse, dmmoore415

Reviewed By: vitalybuka, morehouse

Subscribers: kcc, dvyukov, srhines, mgorny, delcypher, jfb, jdoerfert, #sanitizers, llvm-commits

Tags: #llvm, #sanitizers

Differential Revision: https://reviews.llvm.org/D58184

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@354895 91177308-0d34-0410-b5e6-96231b3b80d8

15 files changed, 986 insertions, 52 deletions

diff --git a/lib/scudo/standalone/CMakeLists.txt b/lib/scudo/standalone/CMakeLists.txt
index 3b45d3fc6..7a3dad673 100644
--- a/lib/scudo/standalone/CMakeLists.txt
+++ b/lib/scudo/standalone/CMakeLists.txt
@@ -33,18 +33,29 @@ if(ANDROID)
   append_list_if(COMPILER_RT_HAS_Z_GLOBAL -Wl,-z,global SCUDO_LINK_FLAGS)
 endif()
 
-set(SCUDO_SOURCES empty.cc)
+set(SCUDO_SOURCES
+  common.cc
+  fuchsia.cc
+  linux.cc)
 
 set(SCUDO_HEADERS
   platform.h
   internal_defs.h
   atomic_helpers.h
-  list.h)
+  list.h
+  mutex.h
+  linux.h)
 
 if(COMPILER_RT_HAS_SCUDO_STANDALONE)
+  add_compiler_rt_object_libraries(RTScudoStandalone
+    ARCHS ${SCUDO_STANDALONE_SUPPORTED_ARCH}
+    SOURCES ${SCUDO_SOURCES}
+    ADDITIONAL_HEADERS ${SCUDO_HEADERS}
+    CFLAGS ${SCUDO_CFLAGS})
+
   add_compiler_rt_runtime(clang_rt.scudo_standalone
     STATIC
-    ARCHS ${SCUDO_SUPPORTED_ARCH}
+    ARCHS ${SCUDO_STANDALONE_SUPPORTED_ARCH}
     SOURCES ${SCUDO_SOURCES}
     ADDITIONAL_HEADERS ${SCUDO_HEADERS}
     CFLAGS ${SCUDO_CFLAGS}
diff --git a/lib/scudo/standalone/atomic_helpers.h b/lib/scudo/standalone/atomic_helpers.h
index a09cd1e50..35d7369c1 100644
--- a/lib/scudo/standalone/atomic_helpers.h
+++ b/lib/scudo/standalone/atomic_helpers.h
@@ -51,7 +51,7 @@ struct atomic_u32 {
 struct atomic_u64 {
   typedef u64 Type;
   // On 32-bit platforms u64 is not necessarily aligned on 8 bytes.
-  volatile ALIGNED(8) Type ValDoNotUse;
+  ALIGNED(8) volatile Type ValDoNotUse;
 };
 
 struct atomic_uptr {
diff --git a/lib/scudo/standalone/common.cc b/lib/scudo/standalone/common.cc
new file mode 100644
index 000000000..2a26efbb9
--- /dev/null
+++ b/lib/scudo/standalone/common.cc
@@ -0,0 +1,32 @@
+//===-- common.cc -----------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "common.h"
+#include "atomic_helpers.h"
+
+namespace scudo {
+
+uptr PageSizeCached;
+uptr getPageSize();
+
+uptr getPageSizeSlow() {
+  PageSizeCached = getPageSize();
+  CHECK_NE(PageSizeCached, 0);
+  return PageSizeCached;
+}
+
+// Fatal internal map() or unmap() error (potentially OOM related).
+void NORETURN dieOnMapUnmapError(bool OutOfMemory) {
+  outputRaw("Scudo ERROR: internal map or unmap failure");
+  if (OutOfMemory)
+    outputRaw(" (OOM)");
+  outputRaw("\n");
+  die();
+}
+
+} // namespace scudo
diff --git a/lib/scudo/standalone/common.h b/lib/scudo/standalone/common.h
new file mode 100644
index 000000000..6bdf9df6c
--- /dev/null
+++ b/lib/scudo/standalone/common.h
@@ -0,0 +1,171 @@
+//===-- common.h ------------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SCUDO_COMMON_H_
+#define SCUDO_COMMON_H_
+
+#include "internal_defs.h"
+
+#include <stddef.h>
+#include <string.h>
+
+namespace scudo {
+
+template <class Dest, class Source> INLINE Dest bit_cast(const Source &S) {
+  COMPILER_CHECK(sizeof(Dest) == sizeof(Source));
+  Dest D;
+  memcpy(&D, &S, sizeof(D));
+  return D;
+}
+
+INLINE constexpr uptr roundUpTo(uptr X, uptr Boundary) {
+  return (X + Boundary - 1) & ~(Boundary - 1);
+}
+
+INLINE constexpr uptr RoundDownTo(uptr X, uptr Boundary) {
+  return X & ~(Boundary - 1);
+}
+
+INLINE constexpr bool isAligned(uptr X, uptr Alignment) {
+  return (X & (Alignment - 1)) == 0;
+}
+
+template <class T> constexpr T Min(T A, T B) { return A < B ? A : B; }
+
+template <class T> constexpr T Max(T A, T B) { return A > B ? A : B; }
+
+template <class T> void Swap(T &A, T &B) {
+  T Tmp = A;
+  A = B;
+  B = Tmp;
+}
+
+INLINE bool isPowerOfTwo(uptr X) { return (X & (X - 1)) == 0; }
+
+INLINE uptr getMostSignificantSetBitIndex(uptr X) {
+  DCHECK_NE(X, 0U);
+  return SCUDO_WORDSIZE - 1U - static_cast<uptr>(__builtin_clzl(X));
+}
+
+INLINE uptr roundUpToPowerOfTwo(uptr Size) {
+  DCHECK(Size);
+  if (isPowerOfTwo(Size))
+    return Size;
+  const uptr Up = getMostSignificantSetBitIndex(Size);
+  DCHECK_LT(Size, (1UL << (Up + 1)));
+  DCHECK_GT(Size, (1UL << Up));
+  return 1UL << (Up + 1);
+}
+
+INLINE uptr getLeastSignificantSetBitIndex(uptr X) {
+  DCHECK_NE(X, 0U);
+  return static_cast<uptr>(__builtin_ctzll(X));
+}
+
+INLINE uptr getLog2(uptr X) {
+  DCHECK(isPowerOfTwo(X));
+  return getLeastSignificantSetBitIndex(X);
+}
+
+INLINE u32 getRandomU32(u32 *State) {
+  // ANSI C linear congruential PRNG (16-bit output).
+  // return (*State = *State * 1103515245 + 12345) >> 16;
+  // XorShift (32-bit output).
+  *State ^= *State << 13;
+  *State ^= *State >> 17;
+  *State ^= *State << 5;
+  return *State;
+}
+
+INLINE u32 getRandomModN(u32 *State, u32 N) {
+  return getRandomU32(State) % N; // [0, N)
+}
+
+template <typename T> INLINE void shuffle(T *A, u32 N, u32 *RandState) {
+  if (N <= 1)
+    return;
+  u32 State = *RandState;
+  for (u32 I = N - 1; I > 0; I--)
+    Swap(A[I], A[getRandomModN(&State, I + 1)]);
+  *RandState = State;
+}
+
+// Hardware specific inlinable functions.
+
+INLINE void yieldProcessor(u8 Count) {
+#if defined(__i386__) || defined(__x86_64__)
+  __asm__ __volatile__("" ::: "memory");
+  for (u8 I = 0; I < Count; I++)
+    __asm__ __volatile__("pause");
+#elif defined(__aarch64__) || defined(__arm__)
+  __asm__ __volatile__("" ::: "memory");
+  for (u8 I = 0; I < Count; I++)
+    __asm__ __volatile__("yield");
+#endif
+  __asm__ __volatile__("" ::: "memory");
+}
+
+// Platform specific functions.
+
+void yieldPlatform();
+
+extern uptr PageSizeCached;
+uptr getPageSizeSlow();
+INLINE uptr getPageSizeCached() {
+  if (LIKELY(PageSizeCached))
+    return PageSizeCached;
+  return getPageSizeSlow();
+}
+
+u32 getNumberOfCPUs();
+
+const char *getEnv(const char *Name);
+
+u64 getMonotonicTime();
+
+// Our randomness gathering function is limited to 256 bytes to ensure we get
+// as many bytes as requested, and avoid interruptions (on Linux).
+constexpr uptr MaxRandomLength = 256U;
+bool getRandom(void *Buffer, uptr Length, bool Blocking = false);
+
+// Platform memory mapping functions.
+
+#define MAP_ALLOWNOMEM (1U << 0)
+#define MAP_NOACCESS (1U << 1)
+#define MAP_RESIZABLE (1U << 2)
+
+// Our platform memory mapping use is restricted to 3 scenarios:
+// - reserve memory at a random address (MAP_NOACCESS);
+// - commit memory in a previously reserved space;
+// - commit memory at a random address.
+// As such, only a subset of parameters combinations is valid, which is checked
+// by the function implementation. The Extra parameter allows to pass opaque
+// platform specific data to the function.
+// Returns nullptr on error or dies if MAP_ALLOWNOMEM is not specified.
+void *map(void *Addr, uptr Size, const char *Name, uptr Flags = 0,
+          u64 *Extra = nullptr);
+
+// Indicates that we are getting rid of the whole mapping, which might have
+// further consequences on Extra, depending on the platform.
+#define UNMAP_ALL (1U << 0)
+
+void unmap(void *Addr, uptr Size, uptr Flags = 0, u64 *Extra = nullptr);
+
+void releasePagesToOS(uptr BaseAddress, uptr Offset, uptr Size,
+                      u64 *Extra = nullptr);
+
+// Internal map & unmap fatal error. This must not call map().
+void NORETURN dieOnMapUnmapError(bool OutOfMemory = false);
+
+// Logging related functions.
+
+void setAbortMessage(const char *Message);
+
+} // namespace scudo
+
+#endif // SCUDO_COMMON_H_
diff --git a/lib/scudo/standalone/empty.cc b/lib/scudo/standalone/empty.cc
deleted file mode 100644
index c0c21d869..000000000
--- a/lib/scudo/standalone/empty.cc
+++ /dev/null
@@ -1,10 +0,0 @@
-//===-- empty.cc ------------------------------------------------*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include "atomic_helpers.h"
-#include "list.h"
diff --git a/lib/scudo/standalone/fuchsia.cc b/lib/scudo/standalone/fuchsia.cc
new file mode 100644
index 000000000..17391d506
--- /dev/null
+++ b/lib/scudo/standalone/fuchsia.cc
@@ -0,0 +1,216 @@
+//===-- fuchsia.cc ----------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "platform.h"
+
+#if SCUDO_FUCHSIA
+
+#include "common.h"
+#include "mutex.h"
+
+#include <limits.h> // for PAGE_SIZE
+#include <stdlib.h> // for abort()
+#include <zircon/process.h>
+#include <zircon/sanitizer.h>
+#include <zircon/syscalls.h>
+
+namespace scudo {
+
+void yieldPlatform() {
+  const zx_status_t Status = _zx_nanosleep(0);
+  CHECK_EQ(Status, ZX_OK);
+}
+
+uptr getPageSize() { return PAGE_SIZE; }
+
+void NORETURN die() { __builtin_trap(); }
+
+// We zero-initialize the Extra parameter of map(), make sure this is consistent
+// with ZX_HANDLE_INVALID.
+COMPILER_CHECK(ZX_HANDLE_INVALID == 0);
+
+struct MapInfo {
+  zx_handle_t Vmar;
+  zx_handle_t Vmo;
+};
+COMPILER_CHECK(sizeof(MapInfo) == sizeof(u64));
+
+static void *allocateVmar(uptr Size, MapInfo *Info, bool AllowNoMem) {
+  // Only scenario so far.
+  DCHECK(Info);
+  DCHECK_EQ(Info->Vmar, ZX_HANDLE_INVALID);
+
+  uintptr_t P;
+  const zx_status_t Status = _zx_vmar_allocate(
+      _zx_vmar_root_self(),
+      ZX_VM_CAN_MAP_READ | ZX_VM_CAN_MAP_WRITE | ZX_VM_CAN_MAP_SPECIFIC, 0,
+      Size, &Info->Vmar, &P);
+  if (Status != ZX_OK) {
+    if (Status != ZX_ERR_NO_MEMORY || !AllowNoMem)
+      dieOnMapUnmapError(Status == ZX_ERR_NO_MEMORY);
+    return nullptr;
+  }
+  return reinterpret_cast<void *>(P);
+}
+
+// Returns the offset of an address range in a Vmar, while checking that said
+// range fully belongs to the Vmar. An alternative would be to keep track of
+// both the base & length to avoid calling this. The tradeoff being a system
+// call vs two extra uptr of storage.
+// TODO(kostyak): revisit the implications of both options.
+static uint64_t getOffsetInVmar(zx_handle_t Vmar, void *Addr, uintptr_t Size) {
+  zx_info_vmar_t Info;
+  const zx_status_t Status = _zx_object_get_info(
+      Vmar, ZX_INFO_VMAR, &Info, sizeof(Info), nullptr, nullptr);
+  CHECK_EQ(Status, ZX_OK);
+  const uint64_t Offset = reinterpret_cast<uintptr_t>(Addr) - Info.base;
+  CHECK_LE(Offset, Info.base + Info.len);
+  CHECK_LE(Offset + Size, Info.base + Info.len);
+  return Offset;
+}
+
+void *map(void *Addr, uptr Size, const char *Name, uptr Flags, u64 *Extra) {
+  DCHECK_EQ(Size % PAGE_SIZE, 0);
+  const bool AllowNoMem = !!(Flags & MAP_ALLOWNOMEM);
+  MapInfo *Info = reinterpret_cast<MapInfo *>(Extra);
+
+  // For MAP_NOACCESS, just allocate a Vmar and return.
+  if (Flags & MAP_NOACCESS)
+    return allocateVmar(Size, Info, AllowNoMem);
+
+  const zx_handle_t Vmar = Info ? Info->Vmar : _zx_vmar_root_self();
+  CHECK_NE(Vmar, ZX_HANDLE_INVALID);
+
+  zx_status_t Status;
+  zx_handle_t Vmo;
+  uint64_t VmoSize = 0;
+  if (Info && Info->Vmo != ZX_HANDLE_INVALID) {
+    // If a Vmo was specified, it's a resize operation.
+    CHECK(Addr);
+    DCHECK(Flags & MAP_RESIZABLE);
+    Vmo = Info->Vmo;
+    Status = _zx_vmo_get_size(Vmo, &VmoSize);
+    if (Status == ZX_OK)
+      Status = _zx_vmo_set_size(Vmo, VmoSize + Size);
+    if (Status != ZX_OK) {
+      if (Status != ZX_ERR_NO_MEMORY || !AllowNoMem)
+        dieOnMapUnmapError(Status == ZX_ERR_NO_MEMORY);
+      return nullptr;
+    }
+  } else {
+    // Otherwise, create a Vmo and set its name.
+    Status = _zx_vmo_create(Size, 0, &Vmo);
+    if (Status != ZX_OK) {
+      if (Status != ZX_ERR_NO_MEMORY || !AllowNoMem)
+        dieOnMapUnmapError(Status == ZX_ERR_NO_MEMORY);
+      return nullptr;
+    }
+    uptr N = 0;
+    while (Name[N])
+      N++;
+    _zx_object_set_property(Vmo, ZX_PROP_NAME, Name, N);
+  }
+
+  uintptr_t P;
+  zx_vm_option_t MapFlags = ZX_VM_PERM_READ | ZX_VM_PERM_WRITE;
+  const uint64_t Offset = Addr ? getOffsetInVmar(Vmar, Addr, Size) : 0;
+  if (Offset)
+    MapFlags |= ZX_VM_SPECIFIC;
+  Status = _zx_vmar_map(Vmar, MapFlags, Offset, Vmo, VmoSize, Size, &P);
+  // No need to track the Vmo if we don't intend on resizing it. Close it.
+  if (Flags & MAP_RESIZABLE) {
+    DCHECK(Info);
+    DCHECK_EQ(Info->Vmo, ZX_HANDLE_INVALID);
+    Info->Vmo = Vmo;
+  } else {
+    CHECK_EQ(_zx_handle_close(Vmo), ZX_OK);
+  }
+  if (Status != ZX_OK) {
+    if (Status != ZX_ERR_NO_MEMORY || !AllowNoMem)
+      dieOnMapUnmapError(Status == ZX_ERR_NO_MEMORY);
+    return nullptr;
+  }
+
+  return reinterpret_cast<void *>(P);
+}
+
+void unmap(void *Addr, uptr Size, uptr Flags, u64 *Extra) {
+  MapInfo *Info = reinterpret_cast<MapInfo *>(Extra);
+  if (Flags & UNMAP_ALL) {
+    DCHECK_NE(Info, nullptr);
+    const zx_handle_t Vmar = Info->Vmar;
+    DCHECK_NE(Vmar, _zx_vmar_root_self());
+    // Destroying the vmar effectively unmaps the whole mapping.
+    CHECK_EQ(_zx_vmar_destroy(Vmar), ZX_OK);
+    CHECK_EQ(_zx_handle_close(Vmar), ZX_OK);
+  } else {
+    const zx_handle_t Vmar = Info ? Info->Vmar : _zx_vmar_root_self();
+    const zx_status_t Status =
+        _zx_vmar_unmap(Vmar, reinterpret_cast<uintptr_t>(Addr), Size);
+    if (Status != ZX_OK)
+      dieOnMapUnmapError();
+  }
+  if (Info) {
+    if (Info->Vmo != ZX_HANDLE_INVALID)
+      CHECK_EQ(_zx_handle_close(Info->Vmo), ZX_OK);
+    Info->Vmo = ZX_HANDLE_INVALID;
+    Info->Vmar = ZX_HANDLE_INVALID;
+  }
+}
+
+void releasePagesToOS(UNUSED uptr BaseAddress, uptr Offset, uptr Size,
+                      u64 *Extra) {
+  MapInfo *Info = reinterpret_cast<MapInfo *>(Extra);
+  DCHECK(Info);
+  DCHECK_NE(Info->Vmar, ZX_HANDLE_INVALID);
+  DCHECK_NE(Info->Vmo, ZX_HANDLE_INVALID);
+  const zx_status_t Status =
+      _zx_vmo_op_range(Info->Vmo, ZX_VMO_OP_DECOMMIT, Offset, Size, NULL, 0);
+  CHECK_EQ(Status, ZX_OK);
+}
+
+const char *getEnv(const char *Name) { return getenv(Name); }
+
+void BlockingMutex::wait() {
+  const zx_status_t Status =
+      _zx_futex_wait(reinterpret_cast<zx_futex_t *>(OpaqueStorage), MtxSleeping,
+                     ZX_HANDLE_INVALID, ZX_TIME_INFINITE);
+  if (Status != ZX_ERR_BAD_STATE)
+    CHECK_EQ(Status, ZX_OK); // Normal race
+}
+
+void BlockingMutex::wake() {
+  const zx_status_t Status =
+      _zx_futex_wake(reinterpret_cast<zx_futex_t *>(OpaqueStorage), 1);
+  CHECK_EQ(Status, ZX_OK);
+}
+
+u64 getMonotonicTime() { return _zx_clock_get(ZX_CLOCK_MONOTONIC); }
+
+u32 getNumberOfCPUs() { return _zx_system_get_num_cpus(); }
+
+bool getRandom(void *Buffer, uptr Length, bool Blocking) {
+  COMPILER_CHECK(MaxRandomLength <= ZX_CPRNG_DRAW_MAX_LEN);
+  if (!Buffer || !Length || Length > MaxRandomLength)
+    return false;
+  _zx_cprng_draw(Buffer, Length);
+  return true;
+}
+
+void outputRaw(const char *Buffer) {
+  uptr N = 0;
+  while (Buffer[N])
+    N++;
+  __sanitizer_log_write(Buffer, N);
+}
+
+void setAbortMessage(const char *Message) {}
+
+} // namespace scudo
+
+#endif // SCUDO_FUCHSIA
diff --git a/lib/scudo/standalone/internal_defs.h b/lib/scudo/standalone/internal_defs.h
index 5c1594552..41ad59173 100644
--- a/lib/scudo/standalone/internal_defs.h
+++ b/lib/scudo/standalone/internal_defs.h
@@ -11,6 +11,8 @@
 
 #include "platform.h"
 
+#include <stdint.h>
+
 #ifndef SCUDO_DEBUG
 #define SCUDO_DEBUG 0
 #endif
@@ -31,6 +33,8 @@
 #define INLINE inline
 #define ALWAYS_INLINE inline __attribute__((always_inline))
 #define ALIAS(x) __attribute__((alias(x)))
+// Please only use the ALIGNED macro before the type. Using ALIGNED after the
+// variable declaration is not portable.
 #define ALIGNED(x) __attribute__((aligned(x)))
 #define FORMAT(f, a) __attribute__((format(printf, f, a)))
 #define NOINLINE __attribute__((noinline))
@@ -61,42 +65,29 @@ typedef signed short s16;
 typedef signed int s32;
 typedef signed long long s64;
 
-// Various integer constants.
-
-#undef __INT64_C
-#undef __UINT64_C
-#undef UINTPTR_MAX
-#if SCUDO_WORDSIZE == 64U
-#define __INT64_C(c) c##L
-#define __UINT64_C(c) c##UL
-#define UINTPTR_MAX (18446744073709551615UL)
-#else
-#define __INT64_C(c) c##LL
-#define __UINT64_C(c) c##ULL
-#define UINTPTR_MAX (4294967295U)
-#endif // SCUDO_WORDSIZE == 64U
-#undef INT32_MIN
-#define INT32_MIN (-2147483647 - 1)
-#undef INT32_MAX
-#define INT32_MAX (2147483647)
-#undef UINT32_MAX
-#define UINT32_MAX (4294967295U)
-#undef INT64_MIN
-#define INT64_MIN (-__INT64_C(9223372036854775807) - 1)
-#undef INT64_MAX
-#define INT64_MAX (__INT64_C(9223372036854775807))
-#undef UINT64_MAX
-#define UINT64_MAX (__UINT64_C(18446744073709551615))
+// The following two functions have platform specific implementations.
+void outputRaw(const char *Buffer);
+void NORETURN die();
 
-enum LinkerInitialized { LINKER_INITIALIZED = 0 };
+#define RAW_CHECK_MSG(Expr, Msg)                                               \
+  do {                                                                         \
+    if (UNLIKELY(!(Expr))) {                                                   \
+      outputRaw(Msg);                                                          \
+      die();                                                                   \
+    }                                                                          \
+  } while (false)
 
-// Various CHECK related macros.
+#define RAW_CHECK(Expr) RAW_CHECK_MSG(Expr, #Expr)
 
-#define COMPILER_CHECK(Pred) static_assert(Pred, "")
-
-// TODO(kostyak): implement at a later check-in.
+// TODO(kostyak): use reportCheckFailed when checked-in.
 #define CHECK_IMPL(c1, op, c2)                                                 \
   do {                                                                         \
+    u64 v1 = (u64)(c1);                                                        \
+    u64 v2 = (u64)(c2);                                                        \
+    if (UNLIKELY(!(v1 op v2))) {                                               \
+      outputRaw("CHECK failed: (" #c1 ") " #op " (" #c2 ")\n");                \
+      die();                                                                   \
+    }                                                                          \
   } while (false)
 
 #define CHECK(a) CHECK_IMPL((a), !=, 0)
@@ -125,10 +116,16 @@ enum LinkerInitialized { LINKER_INITIALIZED = 0 };
 #define DCHECK_GE(a, b)
 #endif
 
-// TODO(kostyak): implement at a later check-in.
+// The superfluous die() call effectively makes this macro NORETURN.
 #define UNREACHABLE(msg)                                                       \
   do {                                                                         \
-  } while (false)
+    CHECK(0 && msg);                                                           \
+    die();                                                                     \
+  } while (0)
+
+#define COMPILER_CHECK(Pred) static_assert(Pred, "")
+
+enum LinkerInitialized { LINKER_INITIALIZED = 0 };
 
 } // namespace scudo
 
diff --git a/lib/scudo/standalone/linux.cc b/lib/scudo/standalone/linux.cc
new file mode 100644
index 000000000..a8be26946
--- /dev/null
+++ b/lib/scudo/standalone/linux.cc
@@ -0,0 +1,151 @@
+//===-- linux.cc ------------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "platform.h"
+
+#if SCUDO_LINUX
+
+#include "common.h"
+#include "linux.h"
+#include "mutex.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/futex.h>
+#include <sched.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/time.h>
+#include <time.h>
+#include <unistd.h>
+
+#if SCUDO_ANDROID
+#include <sys/prctl.h>
+// Definitions of prctl arguments to set a vma name in Android kernels.
+#define ANDROID_PR_SET_VMA 0x53564d41
+#define ANDROID_PR_SET_VMA_ANON_NAME 0
+#endif
+
+namespace scudo {
+
+void yieldPlatform() { sched_yield(); }
+
+uptr getPageSize() { return static_cast<uptr>(sysconf(_SC_PAGESIZE)); }
+
+void NORETURN die() { abort(); }
+
+void *map(void *Addr, uptr Size, UNUSED const char *Name, uptr Flags,
+          UNUSED u64 *Extra) {
+  int MmapFlags = MAP_PRIVATE | MAP_ANON;
+  if (Flags & MAP_NOACCESS)
+    MmapFlags |= MAP_NORESERVE;
+  if (Addr) {
+    // Currently no scenario for a noaccess mapping with a fixed address.
+    DCHECK_EQ(Flags & MAP_NOACCESS, 0);
+    MmapFlags |= MAP_FIXED;
+  }
+  const int MmapProt =
+      (Flags & MAP_NOACCESS) ? PROT_NONE : PROT_READ | PROT_WRITE;
+  void *P = mmap(Addr, Size, MmapProt, MmapFlags, -1, 0);
+  if (P == MAP_FAILED) {
+    if (!(Flags & MAP_ALLOWNOMEM) || errno != ENOMEM)
+      dieOnMapUnmapError(errno == ENOMEM);
+    return nullptr;
+  }
+#if SCUDO_ANDROID
+  if (!(Flags & MAP_NOACCESS))
+    prctl(ANDROID_PR_SET_VMA, ANDROID_PR_SET_VMA_ANON_NAME, P, Size, Name);
+#endif
+  return P;
+}
+
+void unmap(void *Addr, uptr Size, UNUSED uptr Flags, UNUSED u64 *Extra) {
+  if (munmap(Addr, Size) != 0)
+    dieOnMapUnmapError();
+}
+
+void releasePagesToOS(uptr BaseAddress, uptr Offset, uptr Size,
+                      UNUSED u64 *Extra) {
+  void *Addr = reinterpret_cast<void *>(BaseAddress + Offset);
+  while (madvise(Addr, Size, MADV_DONTNEED) == -1 && errno == EAGAIN) {
+  }
+}
+
+// Calling getenv should be fine (c)(tm) at any time.
+const char *getEnv(const char *Name) { return getenv(Name); }
+
+void BlockingMutex::wait() {
+  syscall(SYS_futex, reinterpret_cast<uptr>(OpaqueStorage), FUTEX_WAIT_PRIVATE,
+          MtxSleeping, nullptr, nullptr, 0);
+}
+
+void BlockingMutex::wake() {
+  syscall(SYS_futex, reinterpret_cast<uptr>(OpaqueStorage), FUTEX_WAKE_PRIVATE,
+          1, nullptr, nullptr, 0);
+}
+
+u64 getMonotonicTime() {
+  timespec TS;
+  clock_gettime(CLOCK_MONOTONIC, &TS);
+  return static_cast<u64>(TS.tv_sec) * (1000ULL * 1000 * 1000) +
+         static_cast<u64>(TS.tv_nsec);
+}
+
+u32 getNumberOfCPUs() {
+  cpu_set_t CPUs;
+  CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0);
+  return static_cast<u32>(CPU_COUNT(&CPUs));
+}
+
+// Blocking is possibly unused if the getrandom block is not compiled in.
+bool getRandom(void *Buffer, uptr Length, UNUSED bool Blocking) {
+  if (!Buffer || !Length || Length > MaxRandomLength)
+    return false;
+  ssize_t ReadBytes;
+#if defined(SYS_getrandom)
+#if !defined(GRND_NONBLOCK)
+#define GRND_NONBLOCK 1
+#endif
+  // Up to 256 bytes, getrandom will not be interrupted.
+  ReadBytes =
+      syscall(SYS_getrandom, Buffer, Length, Blocking ? 0 : GRND_NONBLOCK);
+  if (ReadBytes == static_cast<ssize_t>(Length))
+    return true;
+#endif // defined(SYS_getrandom)
+  // Up to 256 bytes, a read off /dev/urandom will not be interrupted.
+  // Blocking is moot here, O_NONBLOCK has no effect when opening /dev/urandom.
+  const int FileDesc = open("/dev/urandom", O_RDONLY);
+  if (FileDesc == -1)
+    return false;
+  ReadBytes = read(FileDesc, Buffer, Length);
+  close(FileDesc);
+  return (ReadBytes == static_cast<ssize_t>(Length));
+}
+
+void outputRaw(const char *Buffer) {
+  static StaticSpinMutex Mutex;
+  SpinMutexLock L(&Mutex);
+  uptr N = 0;
+  while (Buffer[N])
+    N++;
+  write(2, Buffer, N);
+}
+
+extern "C" WEAK void android_set_abort_message(const char *);
+
+void setAbortMessage(const char *Message) {
+  if (&android_set_abort_message)
+    android_set_abort_message(Message);
+}
+
+} // namespace scudo
+
+#endif // SCUDO_LINUX
diff --git a/lib/scudo/standalone/linux.h b/lib/scudo/standalone/linux.h
new file mode 100644
index 000000000..32ed87175
--- /dev/null
+++ b/lib/scudo/standalone/linux.h
@@ -0,0 +1,67 @@
+//===-- linux.h -------------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SCUDO_LINUX_H_
+#define SCUDO_LINUX_H_
+
+#include "platform.h"
+
+#if SCUDO_LINUX
+
+namespace scudo {
+
+#if SCUDO_ANDROID
+
+#if defined(__aarch64__)
+#define __get_tls()                                                            \
+  ({                                                                           \
+    void **__v;                                                                \
+    __asm__("mrs %0, tpidr_el0" : "=r"(__v));                                  \
+    __v;                                                                       \
+  })
+#elif defined(__arm__)
+#define __get_tls()                                                            \
+  ({                                                                           \
+    void **__v;                                                                \
+    __asm__("mrc p15, 0, %0, c13, c0, 3" : "=r"(__v));                         \
+    __v;                                                                       \
+  })
+#elif defined(__i386__)
+#define __get_tls()                                                            \
+  ({                                                                           \
+    void **__v;                                                                \
+    __asm__("movl %%gs:0, %0" : "=r"(__v));                                    \
+    __v;                                                                       \
+  })
+#elif defined(__x86_64__)
+#define __get_tls()                                                            \
+  ({                                                                           \
+    void **__v;                                                                \
+    __asm__("mov %%fs:0, %0" : "=r"(__v));                                     \
+    __v;                                                                       \
+  })
+#else
+#error "Unsupported architecture."
+#endif
+
+// The Android Bionic team has allocated a TLS slot for sanitizers starting
+// with Q, given that Android currently doesn't support ELF TLS. It is used to
+// store sanitizer thread specific data.
+static const int TLS_SLOT_SANITIZER = 8; // TODO(kostyak): 6 for Q!!
+
+ALWAYS_INLINE uptr *getAndroidTlsPtr() {
+  return reinterpret_cast<uptr *>(&__get_tls()[TLS_SLOT_SANITIZER]);
+}
+
+#endif // SCUDO_ANDROID
+
+} // namespace scudo
+
+#endif // SCUDO_LINUX
+
+#endif // SCUDO_LINUX_H_
diff --git a/lib/scudo/standalone/mutex.h b/lib/scudo/standalone/mutex.h
new file mode 100644
index 000000000..6de3810b4
--- /dev/null
+++ b/lib/scudo/standalone/mutex.h
@@ -0,0 +1,108 @@
+//===-- mutex.h -------------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SCUDO_MUTEX_H_
+#define SCUDO_MUTEX_H_
+
+#include "atomic_helpers.h"
+#include "common.h"
+
+namespace scudo {
+
+class StaticSpinMutex {
+public:
+  void init() { atomic_store_relaxed(&State, 0); }
+
+  void lock() {
+    if (tryLock())
+      return;
+    lockSlow();
+  }
+
+  bool tryLock() {
+    return atomic_exchange(&State, 1, memory_order_acquire) == 0;
+  }
+
+  void unlock() { atomic_store(&State, 0, memory_order_release); }
+
+  void checkLocked() { CHECK_EQ(atomic_load_relaxed(&State), 1); }
+
+private:
+  atomic_u8 State;
+
+  void NOINLINE lockSlow() {
+    for (u32 I = 0;; I++) {
+      if (I < 10)
+        yieldProcessor(10);
+      else
+        yieldPlatform();
+      if (atomic_load_relaxed(&State) == 0 &&
+          atomic_exchange(&State, 1, memory_order_acquire) == 0)
+        return;
+    }
+  }
+};
+
+class SpinMutex : public StaticSpinMutex {
+public:
+  SpinMutex() { init(); }
+
+private:
+  SpinMutex(const SpinMutex &) = delete;
+  void operator=(const SpinMutex &) = delete;
+};
+
+enum MutexState { MtxUnlocked = 0, MtxLocked = 1, MtxSleeping = 2 };
+
+class BlockingMutex {
+public:
+  explicit constexpr BlockingMutex(LinkerInitialized) : OpaqueStorage{0} {}
+  BlockingMutex() { memset(this, 0, sizeof(*this)); }
+  void wait();
+  void wake();
+  void lock() {
+    atomic_u32 *M = reinterpret_cast<atomic_u32 *>(&OpaqueStorage);
+    if (atomic_exchange(M, MtxLocked, memory_order_acquire) == MtxUnlocked)
+      return;
+    while (atomic_exchange(M, MtxSleeping, memory_order_acquire) != MtxUnlocked)
+      wait();
+  }
+  void unlock() {
+    atomic_u32 *M = reinterpret_cast<atomic_u32 *>(&OpaqueStorage);
+    const u32 V = atomic_exchange(M, MtxUnlocked, memory_order_release);
+    DCHECK_NE(V, MtxUnlocked);
+    if (V == MtxSleeping)
+      wake();
+  }
+  void checkLocked() {
+    atomic_u32 *M = reinterpret_cast<atomic_u32 *>(&OpaqueStorage);
+    CHECK_NE(MtxUnlocked, atomic_load_relaxed(M));
+  }
+
+private:
+  uptr OpaqueStorage[1];
+};
+
+template <typename MutexType> class GenericScopedLock {
+public:
+  explicit GenericScopedLock(MutexType *M) : Mutex(M) { Mutex->lock(); }
+  ~GenericScopedLock() { Mutex->unlock(); }
+
+private:
+  MutexType *Mutex;
+
+  GenericScopedLock(const GenericScopedLock &) = delete;
+  void operator=(const GenericScopedLock &) = delete;
+};
+
+typedef GenericScopedLock<StaticSpinMutex> SpinMutexLock;
+typedef GenericScopedLock<BlockingMutex> BlockingMutexLock;
+
+} // namespace scudo
+
+#endif // SCUDO_MUTEX_H_
diff --git a/lib/scudo/standalone/tests/CMakeLists.txt b/lib/scudo/standalone/tests/CMakeLists.txt
index 67038d2b3..fe63dcf04 100644
--- a/lib/scudo/standalone/tests/CMakeLists.txt
+++ b/lib/scudo/standalone/tests/CMakeLists.txt
@@ -34,11 +34,14 @@ macro(add_scudo_unittest testname)
   if(COMPILER_RT_HAS_SCUDO_STANDALONE)
     foreach(arch ${SCUDO_TEST_ARCH})
       set(ScudoUnitTestsObjects)
+      add_library("RTScudoStandalone.test.${arch}"
+        $<TARGET_OBJECTS:RTScudoStandalone.${arch}>)
       generate_compiler_rt_tests(ScudoUnitTestsObjects ScudoUnitTests
         "${testname}-${arch}-Test" ${arch}
-        SOURCES ${TEST_SOURCES} ${COMPILER_RT_GTEST_SOURCE} 
+        SOURCES ${TEST_SOURCES} ${COMPILER_RT_GTEST_SOURCE}
         COMPILE_DEPS ${TEST_HEADERS}
         DEPS gtest scudo_standalone
+        RUNTIME RTScudoStandalone.test.${arch}
         CFLAGS ${SCUDO_UNITTEST_CFLAGS}
         LINK_FLAGS ${LINK_FLAGS})
     endforeach()
@@ -48,6 +51,8 @@ endmacro()
 set(SCUDO_UNIT_TEST_SOURCES
   atomic_test.cc
   list_test.cc
+  map_test.cc
+  mutex_test.cc
   scudo_unit_test_main.cc)
 
 add_scudo_unittest(ScudoUnitTest
diff --git a/lib/scudo/standalone/tests/atomic_test.cc b/lib/scudo/standalone/tests/atomic_test.cc
index 0ef0fa751..3095451b9 100644
--- a/lib/scudo/standalone/tests/atomic_test.cc
+++ b/lib/scudo/standalone/tests/atomic_test.cc
@@ -45,7 +45,7 @@ void checkStoreLoad() {
   EXPECT_EQ(Val.Magic1, (Type)-3);
 }
 
-TEST(ScudoStandalone, AtomicStoreLoad) {
+TEST(ScudoAtomicTest, AtomicStoreLoad) {
   checkStoreLoad<atomic_u8, memory_order_relaxed, memory_order_relaxed>();
   checkStoreLoad<atomic_u8, memory_order_consume, memory_order_relaxed>();
   checkStoreLoad<atomic_u8, memory_order_acquire, memory_order_relaxed>();
@@ -101,7 +101,7 @@ template <typename T> void checkAtomicCompareExchange() {
   }
 }
 
-TEST(ScudoStandalone, AtomicCompareExchangeTest) {
+TEST(ScudoAtomicTest, AtomicCompareExchangeTest) {
   checkAtomicCompareExchange<atomic_u8>();
   checkAtomicCompareExchange<atomic_u16>();
   checkAtomicCompareExchange<atomic_u32>();
diff --git a/lib/scudo/standalone/tests/list_test.cc b/lib/scudo/standalone/tests/list_test.cc
index bf3d71fa1..e4053d8b0 100644
--- a/lib/scudo/standalone/tests/list_test.cc
+++ b/lib/scudo/standalone/tests/list_test.cc
@@ -58,7 +58,7 @@ static void checkList(List *L, ListItem *I1, ListItem *I2 = nullptr,
   EXPECT_TRUE(L->empty());
 }
 
-TEST(ScudoSandalone, IntrusiveList) {
+TEST(ScudoListTest, IntrusiveList) {
   ListItem Items[6];
   EXPECT_EQ(StaticList.size(), 0U);
 
@@ -167,7 +167,7 @@ TEST(ScudoSandalone, IntrusiveList) {
   EXPECT_TRUE(L2.empty());
 }
 
-TEST(ScudoStandalone, IntrusiveListAppendEmpty) {
+TEST(ScudoListTest, IntrusiveListAppendEmpty) {
   ListItem I;
   List L;
   L.clear();
diff --git a/lib/scudo/standalone/tests/map_test.cc b/lib/scudo/standalone/tests/map_test.cc
new file mode 100644
index 000000000..ee627d614
--- /dev/null
+++ b/lib/scudo/standalone/tests/map_test.cc
@@ -0,0 +1,65 @@
+//===-- map_test.cc----------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "common.h"
+
+#include "gtest/gtest.h"
+
+#include <string.h>
+
+const char *MappingName = "scudo:test";
+
+TEST(ScudoMapTest, MapNoAccessUnmap) {
+  const scudo::uptr Size = 4 * scudo::getPageSizeCached();
+  scudo::u64 PlatformData = 0;
+  void *P = scudo::map(nullptr, Size, MappingName, MAP_NOACCESS, &PlatformData);
+  EXPECT_NE(P, nullptr);
+  EXPECT_DEATH(memset(P, 0xaa, Size), "");
+  scudo::unmap(P, Size, UNMAP_ALL, &PlatformData);
+}
+
+TEST(ScudoMapTest, MapUnmap) {
+  const scudo::uptr Size = 4 * scudo::getPageSizeCached();
+  scudo::u64 PlatformData = 0;
+  void *P = scudo::map(nullptr, Size, MappingName, 0, &PlatformData);
+  EXPECT_NE(P, nullptr);
+  memset(P, 0xaa, Size);
+  scudo::unmap(P, Size, 0, &PlatformData);
+  EXPECT_DEATH(memset(P, 0xbb, Size), "");
+}
+
+TEST(ScudoMapTest, MapWithGuardUnmap) {
+  const scudo::uptr PageSize = scudo::getPageSizeCached();
+  const scudo::uptr Size = 4 * PageSize;
+  scudo::u64 PlatformData = 0;
+  void *P = scudo::map(nullptr, Size + 2 * PageSize, MappingName, MAP_NOACCESS,
+                       &PlatformData);
+  EXPECT_NE(P, nullptr);
+  void *Q =
+      reinterpret_cast<void *>(reinterpret_cast<scudo::uptr>(P) + PageSize);
+  EXPECT_EQ(scudo::map(Q, Size, MappingName, 0, &PlatformData), Q);
+  memset(Q, 0xaa, Size);
+  EXPECT_DEATH(memset(Q, 0xaa, Size + 1), "");
+  scudo::unmap(P, Size + 2 * PageSize, UNMAP_ALL, &PlatformData);
+}
+
+TEST(ScudoMapTest, MapGrowUnmap) {
+  const scudo::uptr PageSize = scudo::getPageSizeCached();
+  const scudo::uptr Size = 4 * PageSize;
+  scudo::u64 PlatformData = 0;
+  void *P = scudo::map(nullptr, Size, MappingName, MAP_NOACCESS, &PlatformData);
+  EXPECT_NE(P, nullptr);
+  void *Q =
+      reinterpret_cast<void *>(reinterpret_cast<scudo::uptr>(P) + PageSize);
+  EXPECT_EQ(scudo::map(Q, PageSize, MappingName, 0, &PlatformData), Q);
+  memset(Q, 0xaa, PageSize);
+  Q = reinterpret_cast<void *>(reinterpret_cast<scudo::uptr>(Q) + PageSize);
+  EXPECT_EQ(scudo::map(Q, PageSize, MappingName, 0, &PlatformData), Q);
+  memset(Q, 0xbb, PageSize);
+  scudo::unmap(P, Size, UNMAP_ALL, &PlatformData);
+}
diff --git a/lib/scudo/standalone/tests/mutex_test.cc b/lib/scudo/standalone/tests/mutex_test.cc
new file mode 100644
index 000000000..9e898ebc9
--- /dev/null
+++ b/lib/scudo/standalone/tests/mutex_test.cc
@@ -0,0 +1,121 @@
+//===-- mutex_test.cc--------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "mutex.h"
+
+#include "gtest/gtest.h"
+
+#include <string.h>
+
+template <typename MutexType> class TestData {
+public:
+  explicit TestData(MutexType *M) : Mutex(M) {
+    for (scudo::u32 I = 0; I < Size; I++)
+      Data[I] = 0;
+  }
+
+  void write() {
+    Lock L(Mutex);
+    T V0 = Data[0];
+    for (scudo::u32 I = 0; I < Size; I++) {
+      EXPECT_EQ(Data[I], V0);
+      Data[I]++;
+    }
+  }
+
+  void tryWrite() {
+    if (!Mutex->tryLock())
+      return;
+    T V0 = Data[0];
+    for (scudo::u32 I = 0; I < Size; I++) {
+      EXPECT_EQ(Data[I], V0);
+      Data[I]++;
+    }
+    Mutex->unlock();
+  }
+
+  void backoff() {
+    volatile T LocalData[Size] = {};
+    for (scudo::u32 I = 0; I < Size; I++) {
+      LocalData[I]++;
+      EXPECT_EQ(LocalData[I], 1U);
+    }
+  }
+
+private:
+  typedef scudo::GenericScopedLock<MutexType> Lock;
+  static const scudo::u32 Size = 64U;
+  typedef scudo::u64 T;
+  MutexType *Mutex;
+  ALIGNED(SCUDO_CACHE_LINE_SIZE) T Data[Size];
+};
+
+const scudo::u32 NumberOfThreads = 8;
+#if SCUDO_DEBUG
+const scudo::u32 NumberOfIterations = 4 * 1024;
+#else
+const scudo::u32 NumberOfIterations = 16 * 1024;
+#endif
+
+template <typename MutexType> static void *lockThread(void *Param) {
+  TestData<MutexType> *Data = reinterpret_cast<TestData<MutexType> *>(Param);
+  for (scudo::u32 I = 0; I < NumberOfIterations; I++) {
+    Data->write();
+    Data->backoff();
+  }
+  return 0;
+}
+
+template <typename MutexType> static void *tryThread(void *Param) {
+  TestData<MutexType> *Data = reinterpret_cast<TestData<MutexType> *>(Param);
+  for (scudo::u32 I = 0; I < NumberOfIterations; I++) {
+    Data->tryWrite();
+    Data->backoff();
+  }
+  return 0;
+}
+
+template <typename MutexType> static void checkLocked(MutexType *M) {
+  scudo::GenericScopedLock<MutexType> L(M);
+  M->checkLocked();
+}
+
+TEST(ScudoMutexTest, SpinMutex) {
+  scudo::SpinMutex M;
+  M.init();
+  TestData<scudo::SpinMutex> Data(&M);
+  pthread_t Threads[NumberOfThreads];
+  for (scudo::u32 I = 0; I < NumberOfThreads; I++)
+    pthread_create(&Threads[I], 0, lockThread<scudo::SpinMutex>, &Data);
+  for (scudo::u32 I = 0; I < NumberOfThreads; I++)
+    pthread_join(Threads[I], 0);
+}
+
+TEST(ScudoMutexTest, SpinMutexTry) {
+  scudo::SpinMutex M;
+  M.init();
+  TestData<scudo::SpinMutex> Data(&M);
+  pthread_t Threads[NumberOfThreads];
+  for (scudo::u32 I = 0; I < NumberOfThreads; I++)
+    pthread_create(&Threads[I], 0, tryThread<scudo::SpinMutex>, &Data);
+  for (scudo::u32 I = 0; I < NumberOfThreads; I++)
+    pthread_join(Threads[I], 0);
+}
+
+TEST(ScudoMutexTest, BlockingMutex) {
+  scudo::u64 MutexMemory[1024] = {};
+  scudo::BlockingMutex *M =
+      new (MutexMemory) scudo::BlockingMutex(scudo::LINKER_INITIALIZED);
+  TestData<scudo::BlockingMutex> Data(M);
+  pthread_t Threads[NumberOfThreads];
+  for (scudo::u32 I = 0; I < NumberOfThreads; I++)
+    pthread_create(&Threads[I], 0, lockThread<scudo::BlockingMutex>, &Data);
+  for (scudo::u32 I = 0; I < NumberOfThreads; I++)
+    pthread_join(Threads[I], 0);
+  checkLocked(M);
+}