[Sanitizers] TSan allocator set errno on failure.

[alekseyshl]

Summary

Set proper errno code on allocation failures and change realloc, pvalloc,
aligned_alloc, memalign and posix_memalign implementation to satisfy
their man-specified requirements.

Modify allocator API implementation to bring it closer to other
sanitizers allocators.

[dvyukov]

lib/tsan/rtl/tsan_mman.cc

175

Please don't prefix functions, variables and types in tsan with tsan. It's all tsan already. It's just plain pointless to prefix everything in tsan with tsan, everything in asan with asan, etc, and does not add any information for reader about purpose of a function or a type.

Also, diff will be much smaller if you name this function user_alloc and rename the old one to, say, user_alloc_noerrno. It will be just few lines instead of churning the whole codebase.

[alekseyshl]

• Do not use "tsan_" prefix.

[alekseyshl]

lib/tsan/rtl/tsan_mman.cc

175

Well, not sure about a few lines, but will do. It just seem weird to mention errno in the code which does not care about errno at all. Maybe user_alloc_internal?

[dvyukov]

lib/tsan/rtl/tsan_mman.cc

175

Much better now. Thanks.
user_alloc_internal is fine.

lib/tsan/tests/unit/tsan_mman_test.cc

73

Is there a particular reason for this change? If not, then I would prefer to leave the current behavior. It worked for 5 years. We don't know what will happen with this one.

test/tsan/allocator_returns_null.cc

40

Are C++ tsan tests run on windows? That's surprising to me.

[dvyukov]

lib/tsan/tests/unit/tsan_mman_test.cc

73

Note: the current behavior is correct according to both POSIX, linux man pages and C:

If size is 0, either a null pointer or a unique pointer that can be successfully passed to free() shall be returned.

If size was equal to 0, either NULL or a pointer suitable to be passed to free() is returned.

[alekseyshl]

lib/tsan/tests/unit/tsan_mman_test.cc

73

Wait, that's what the man I quoted in comments: "if size is equal to zero, and ptr is not NULL, then the call is equivalent to free(ptr)", so I'm freeing the pointer and it seems only natural to return NULL in this case, cause what else would I return?

What you're saying is correct for user_realloc(thr, pc, NULL, 0) case.

[alekseyshl]

• Address comments

[alekseyshl]

lib/tsan/tests/unit/tsan_mman_test.cc

73

What I mean to say, it seems strange to return a dangling pointer and stdlib's realloc returns NULL in this case anyway.

user_realloc(thr, pc, NULL, 0) is tested first hand in this test.

test/tsan/allocator_returns_null.cc

40

Yep, got carried away unifying tests with other sanitizers.

[dvyukov]

lib/tsan/tests/unit/tsan_mman_test.cc

73

Okay, let's try this.

lib/tsan/rtl/tsan_fd.cc

 static FdContext fdctx;
 
 static bool bogusfd(int fd) {
   // Apparently a bogus fd value.
   return fd < 0 || fd >= kTableSize;
 }
 
 static FdSync *allocsync(ThreadState *thr, uptr pc) {
-  FdSync *s = (FdSync*)user_alloc(thr, pc, sizeof(FdSync), kDefaultAlignment,
-      false);
+  FdSync *s = (FdSync*)user_alloc_internal(thr, pc, sizeof(FdSync),
+      kDefaultAlignment, false);
   atomic_store(&s->rc, 1, memory_order_relaxed);
   return s;
 }
 
 static FdSync *ref(FdSync *s) {
   if (s && atomic_load(&s->rc, memory_order_relaxed) != (u64)-1)
     atomic_fetch_add(&s->rc, 1, memory_order_relaxed);
   return s;

 static FdDesc *fddesc(ThreadState *thr, uptr pc, int fd) {
   CHECK_GE(fd, 0);
   CHECK_LT(fd, kTableSize);
   atomic_uintptr_t *pl1 = &fdctx.tab[fd / kTableSizeL2];
   uptr l1 = atomic_load(pl1, memory_order_consume);
   if (l1 == 0) {
     uptr size = kTableSizeL2 * sizeof(FdDesc);
     // We need this to reside in user memory to properly catch races on it.
-    void *p = user_alloc(thr, pc, size, kDefaultAlignment, false);
+    void *p = user_alloc_internal(thr, pc, size, kDefaultAlignment, false);
     internal_memset(p, 0, size);
     MemoryResetRange(thr, (uptr)&fddesc, (uptr)p, size);
     if (atomic_compare_exchange_strong(pl1, &l1, (uptr)p, memory_order_acq_rel))
       l1 = (uptr)p;
     else
       user_free(thr, pc, p, false);
   }
   return &((FdDesc*)l1)[fd % kTableSizeL2];  // NOLINT

lib/tsan/rtl/tsan_interceptors.cc

void *p = 0;
     p = user_alloc(thr, pc, size);
   }
   invoke_malloc_hook(p, size);
   return p;
 }
 
 TSAN_INTERCEPTOR(void*, __libc_memalign, uptr align, uptr sz) {
   SCOPED_TSAN_INTERCEPTOR(__libc_memalign, align, sz);
-  return user_alloc(thr, pc, sz, align);
+  return user_memalign(thr, pc, align, sz);
 }
 
 TSAN_INTERCEPTOR(void*, calloc, uptr size, uptr n) {
   if (cur_thread()->in_symbolizer)
     return InternalCalloc(size, n);
   void *p = 0;
   {
     SCOPED_INTERCEPTOR_RAW(calloc, size, n);
TSAN_INTERCEPTOR(int, munmap, void *addr, long_t sz) {
   }
   int res = REAL(munmap)(addr, sz);
   return res;
 }
 
 #if SANITIZER_LINUX
 TSAN_INTERCEPTOR(void*, memalign, uptr align, uptr sz) {
   SCOPED_INTERCEPTOR_RAW(memalign, align, sz);
-  return user_alloc(thr, pc, sz, align);
+  return user_memalign(thr, pc, align, sz);
 }
 #define TSAN_MAYBE_INTERCEPT_MEMALIGN TSAN_INTERCEPT(memalign)
 #else
 #define TSAN_MAYBE_INTERCEPT_MEMALIGN
 #endif
 
 #if !SANITIZER_MAC
 TSAN_INTERCEPTOR(void*, aligned_alloc, uptr align, uptr sz) {
-  SCOPED_INTERCEPTOR_RAW(memalign, align, sz);
-  return user_alloc(thr, pc, sz, align);
+  SCOPED_INTERCEPTOR_RAW(aligned_alloc, align, sz);
+  return user_aligned_alloc(thr, pc, align, sz);
 }
 
 TSAN_INTERCEPTOR(void*, valloc, uptr sz) {
   SCOPED_INTERCEPTOR_RAW(valloc, sz);
-  return user_alloc(thr, pc, sz, GetPageSizeCached());
+  return user_valloc(thr, pc, sz);
 }
 #endif
 
 #if SANITIZER_LINUX
 TSAN_INTERCEPTOR(void*, pvalloc, uptr sz) {
   SCOPED_INTERCEPTOR_RAW(pvalloc, sz);
-  sz = RoundUp(sz, GetPageSizeCached());
-  return user_alloc(thr, pc, sz, GetPageSizeCached());
+  return user_pvalloc(thr, pc, sz);
 }
 #define TSAN_MAYBE_INTERCEPT_PVALLOC TSAN_INTERCEPT(pvalloc)
 #else
 #define TSAN_MAYBE_INTERCEPT_PVALLOC
 #endif
 
 #if !SANITIZER_MAC
 TSAN_INTERCEPTOR(int, posix_memalign, void **memptr, uptr align, uptr sz) {
   SCOPED_INTERCEPTOR_RAW(posix_memalign, memptr, align, sz);
-  *memptr = user_alloc(thr, pc, sz, align);
-  return 0;
+  return user_posix_memalign(thr, pc, memptr, align, sz);
 }
 #endif
 
 // __cxa_guard_acquire and friends need to be intercepted in a special way -
 // regular interceptors will break statically-linked libstdc++. Linux
 // interceptors are especially defined as weak functions (so that they don't
 // cause link errors when user defines them as well). So they silently
 // auto-disable themselves when such symbol is already present in the binary. If

lib/tsan/rtl/tsan_libdispatch_mac.cc

static dispatch_queue_t GetTargetQueueFromSource(dispatch_source_t source) {
   return tq;
 }
 
 static tsan_block_context_t *AllocContext(ThreadState *thr, uptr pc,
                                           dispatch_queue_t queue,
                                           void *orig_context,
                                           dispatch_function_t orig_work) {
   tsan_block_context_t *new_context =
-      (tsan_block_context_t *)user_alloc(thr, pc, sizeof(tsan_block_context_t));
+      (tsan_block_context_t *)user_alloc_internal(thr, pc,
+                                                  sizeof(tsan_block_context_t));
   new_context->queue = queue;
   new_context->orig_context = orig_context;
   new_context->orig_work = orig_work;
   new_context->free_context_in_callback = true;
   new_context->submitted_synchronously = false;
   new_context->is_barrier_block = false;
   new_context->non_queue_sync_object = 0;
   return new_context;

lib/tsan/rtl/tsan_malloc_mac.cc

 using namespace __tsan;
 #define COMMON_MALLOC_ZONE_NAME "tsan"
 #define COMMON_MALLOC_ENTER()
 #define COMMON_MALLOC_SANITIZER_INITIALIZED (cur_thread()->is_inited)
 #define COMMON_MALLOC_FORCE_LOCK()
 #define COMMON_MALLOC_FORCE_UNLOCK()
 #define COMMON_MALLOC_MEMALIGN(alignment, size) \
   void *p =                                     \
-      user_alloc(cur_thread(), StackTrace::GetCurrentPc(), size, alignment)
+      user_memalign(cur_thread(), StackTrace::GetCurrentPc(), alignment, size)
 #define COMMON_MALLOC_MALLOC(size)                             \
   if (cur_thread()->in_symbolizer) return InternalAlloc(size); \
   SCOPED_INTERCEPTOR_RAW(malloc, size);                        \
   void *p = user_alloc(thr, pc, size)
 #define COMMON_MALLOC_REALLOC(ptr, size)                              \
   if (cur_thread()->in_symbolizer) return InternalRealloc(ptr, size); \
   SCOPED_INTERCEPTOR_RAW(realloc, ptr, size);                         \
   void *p = user_realloc(thr, pc, ptr, size)
 #define COMMON_MALLOC_CALLOC(count, size)                              \
   if (cur_thread()->in_symbolizer) return InternalCalloc(count, size); \
   SCOPED_INTERCEPTOR_RAW(calloc, size, count);                         \
   void *p = user_calloc(thr, pc, size, count)
 #define COMMON_MALLOC_VALLOC(size)                            \
   if (cur_thread()->in_symbolizer)                            \
     return InternalAlloc(size, nullptr, GetPageSizeCached()); \
   SCOPED_INTERCEPTOR_RAW(valloc, size);                       \
-  void *p = user_alloc(thr, pc, size, GetPageSizeCached())
+  void *p = user_valloc(thr, pc, size)
 #define COMMON_MALLOC_FREE(ptr)                              \
   if (cur_thread()->in_symbolizer) return InternalFree(ptr); \
   SCOPED_INTERCEPTOR_RAW(free, ptr);                         \
   user_free(thr, pc, ptr)
 #define COMMON_MALLOC_SIZE(ptr) uptr size = user_alloc_usable_size(ptr);
 #define COMMON_MALLOC_FILL_STATS(zone, stats)
 #define COMMON_MALLOC_REPORT_UNKNOWN_REALLOC(ptr, zone_ptr, zone_name) \
   (void)zone_name; \
   Report("mz_realloc(%p) -- attempting to realloc unallocated memory.\n", ptr);
 #define COMMON_MALLOC_NAMESPACE __tsan
 
 #include "sanitizer_common/sanitizer_malloc_mac.inc"
 
 #endif

lib/tsan/rtl/tsan_mman.h

 void InitializeAllocator();
 void InitializeAllocatorLate();
 void ReplaceSystemMalloc();
 void AllocatorProcStart(Processor *proc);
 void AllocatorProcFinish(Processor *proc);
 void AllocatorPrintStats();
 
 // For user allocations.
-void *user_alloc(ThreadState *thr, uptr pc, uptr sz,
+void *user_alloc_internal(ThreadState *thr, uptr pc, uptr sz,
                           uptr align = kDefaultAlignment, bool signal = true);
-void *user_calloc(ThreadState *thr, uptr pc, uptr sz, uptr n);
 // Does not accept NULL.
 void user_free(ThreadState *thr, uptr pc, void *p, bool signal = true);
+// Interceptor implementations.
+void *user_alloc(ThreadState *thr, uptr pc, uptr sz);
+void *user_calloc(ThreadState *thr, uptr pc, uptr sz, uptr n);
 void *user_realloc(ThreadState *thr, uptr pc, void *p, uptr sz);
-void *user_alloc_aligned(ThreadState *thr, uptr pc, uptr sz, uptr align);
+void *user_memalign(ThreadState *thr, uptr pc, uptr align, uptr sz);
+int user_posix_memalign(ThreadState *thr, uptr pc, void **memptr, uptr align,
+                        uptr sz);
+void *user_aligned_alloc(ThreadState *thr, uptr pc, uptr align, uptr sz);
+void *user_valloc(ThreadState *thr, uptr pc, uptr sz);
+void *user_pvalloc(ThreadState *thr, uptr pc, uptr sz);
 uptr user_alloc_usable_size(const void *p);
 
 // Invoking malloc/free hooks that may be installed by the user.
 void invoke_malloc_hook(void *ptr, uptr size);
 void invoke_free_hook(void *ptr);
 
 enum MBlockType {
   MBlockScopedBuf,

lib/tsan/rtl/tsan_mman.cc

static void SignalUnsafeCall(ThreadState *thr, uptr pc) {
   if (IsFiredSuppression(ctx, ReportTypeSignalUnsafe, stack))
     return;
   ThreadRegistryLock l(ctx->thread_registry);
   ScopedReport rep(ReportTypeSignalUnsafe);
   rep.AddStack(stack, true);
   OutputReport(thr, rep);
 }
 
-void *user_alloc(ThreadState *thr, uptr pc, uptr sz, uptr align, bool signal) {
+void *user_alloc_internal(ThreadState *thr, uptr pc, uptr sz, uptr align,
+                          bool signal) {
   if ((sz >= (1ull << 40)) || (align >= (1ull << 40)))
     return Allocator::FailureHandler::OnBadRequest();
   void *p = allocator()->Allocate(&thr->proc()->alloc_cache, sz, align);
-  if (p == 0)
+  if (UNLIKELY(p == 0))
     return 0;
   if (ctx && ctx->initialized)
     OnUserAlloc(thr, pc, (uptr)p, sz, true);
   if (signal)
     SignalUnsafeCall(thr, pc);
   return p;
 }
 
-void *user_calloc(ThreadState *thr, uptr pc, uptr size, uptr n) {
-  if (CheckForCallocOverflow(size, n))
-    return Allocator::FailureHandler::OnBadRequest();
-  void *p = user_alloc(thr, pc, n * size);
-  if (p)
-    internal_memset(p, 0, n * size);
-  return p;
-}
-
 void user_free(ThreadState *thr, uptr pc, void *p, bool signal) {
   ScopedGlobalProcessor sgp;
   if (ctx && ctx->initialized)
     OnUserFree(thr, pc, (uptr)p, true);
   allocator()->Deallocate(&thr->proc()->alloc_cache, p);
   if (signal)
     SignalUnsafeCall(thr, pc);
 }
 
+void *user_alloc(ThreadState *thr, uptr pc, uptr sz) {
+  return SetErrnoOnNull(user_alloc_internal(thr, pc, sz, kDefaultAlignment));
+}
+
+void *user_calloc(ThreadState *thr, uptr pc, uptr size, uptr n) {
+  if (UNLIKELY(CheckForCallocOverflow(size, n)))
+    return SetErrnoOnNull(Allocator::FailureHandler::OnBadRequest());
+  void *p = user_alloc_internal(thr, pc, n * size);
+  if (p)
+    internal_memset(p, 0, n * size);
+  return SetErrnoOnNull(p);
+}
+
 void OnUserAlloc(ThreadState *thr, uptr pc, uptr p, uptr sz, bool write) {
   DPrintf("#%d: alloc(%zu) = %p\n", thr->tid, sz, p);
   ctx->metamap.AllocBlock(thr, pc, p, sz);
   if (write && thr->ignore_reads_and_writes == 0)
     MemoryRangeImitateWrite(thr, pc, (uptr)p, sz);
   else
     MemoryResetRange(thr, pc, (uptr)p, sz);
 }
 
 void OnUserFree(ThreadState *thr, uptr pc, uptr p, bool write) {
   CHECK_NE(p, (void*)0);
   uptr sz = ctx->metamap.FreeBlock(thr->proc(), p);
   DPrintf("#%d: free(%p, %zu)\n", thr->tid, p, sz);
   if (write && thr->ignore_reads_and_writes == 0)
     MemoryRangeFreed(thr, pc, (uptr)p, sz);
 }
 
 void *user_realloc(ThreadState *thr, uptr pc, void *p, uptr sz) {
   // FIXME: Handle "shrinking" more efficiently,
   // it seems that some software actually does this.
-  void *p2 = user_alloc(thr, pc, sz);
-  if (p2 == 0)
-    return 0;
-  if (p) {
-    uptr oldsz = user_alloc_usable_size(p);
-    internal_memcpy(p2, p, min(oldsz, sz));
+  if (!p)
+    return SetErrnoOnNull(user_alloc_internal(thr, pc, sz));
+  if (!sz) {
     user_free(thr, pc, p);
+    return nullptr;
   }
-  return p2;
+  void *new_p = user_alloc_internal(thr, pc, sz);
+  if (new_p) {
+    uptr old_sz = user_alloc_usable_size(p);
+    internal_memcpy(new_p, p, min(old_sz, sz));
+    user_free(thr, pc, p);
+  }
+  return SetErrnoOnNull(new_p);
+}
+
+void *user_memalign(ThreadState *thr, uptr pc, uptr align, uptr sz) {
+  if (UNLIKELY(!IsPowerOfTwo(align))) {
+    errno = errno_EINVAL;
+    return Allocator::FailureHandler::OnBadRequest();
+  }
+  return SetErrnoOnNull(user_alloc_internal(thr, pc, sz, align));
+}
+
+int user_posix_memalign(ThreadState *thr, uptr pc, void **memptr, uptr align,
+                        uptr sz) {
+  if (UNLIKELY(!CheckPosixMemalignAlignment(align))) {
+    Allocator::FailureHandler::OnBadRequest();
+    return errno_EINVAL;
+  }
+  void *ptr = user_alloc_internal(thr, pc, sz, align);
+  if (UNLIKELY(!ptr))
+    return errno_ENOMEM;
+  CHECK(IsAligned((uptr)ptr, align));
+  *memptr = ptr;
+  return 0;
+}
+
+void *user_aligned_alloc(ThreadState *thr, uptr pc, uptr align, uptr sz) {
+  if (UNLIKELY(!CheckAlignedAllocAlignmentAndSize(align, sz))) {
+    errno = errno_EINVAL;
+    return Allocator::FailureHandler::OnBadRequest();
+  }
+  return SetErrnoOnNull(user_alloc_internal(thr, pc, sz, align));
+}
+
+void *user_valloc(ThreadState *thr, uptr pc, uptr sz) {
+  return SetErrnoOnNull(user_alloc_internal(thr, pc, sz, GetPageSizeCached()));
+}
+
+void *user_pvalloc(ThreadState *thr, uptr pc, uptr sz) {
+  uptr PageSize = GetPageSizeCached();
+  // pvalloc(0) should allocate one page.
+  sz = sz ? RoundUpTo(sz, PageSize) : PageSize;
+  return SetErrnoOnNull(user_alloc_internal(thr, pc, sz, PageSize));
 }
 
 uptr user_alloc_usable_size(const void *p) {
   if (p == 0)
     return 0;
   MBlock *b = ctx->metamap.GetBlock((uptr)p);
   if (!b)
     return 0;  // Not a valid pointer.

lib/tsan/tests/unit/tsan_mman_test.cc

 TEST(Mman, UserRealloc) {
   ThreadState *thr = cur_thread();
   uptr pc = 0;
   {
     void *p = user_realloc(thr, pc, 0, 0);
     // Realloc(NULL, N) is equivalent to malloc(N), thus must return
     // non-NULL pointer.
     EXPECT_NE(p, (void*)0);
+    user_free(thr, pc, p);
   }
   {
     void *p = user_realloc(thr, pc, 0, 100);
     EXPECT_NE(p, (void*)0);
     memset(p, 0xde, 100);
     user_free(thr, pc, p);
   }
   {
     void *p = user_alloc(thr, pc, 100);
     EXPECT_NE(p, (void*)0);
     memset(p, 0xde, 100);
+    // Realloc(P, 0) is equivalent to free(P) and returns NULL.
     void *p2 = user_realloc(thr, pc, p, 0);
-    EXPECT_NE(p2, (void*)0);
+    EXPECT_EQ(p2, (void*)0);
   }
   {
     void *p = user_realloc(thr, pc, 0, 100);
     EXPECT_NE(p, (void*)0);
     memset(p, 0xde, 100);
     void *p2 = user_realloc(thr, pc, p, 10000);
     EXPECT_NE(p2, (void*)0);
     for (int i = 0; i < 100; i++)
TEST(Mman, Stats) {
   user_free(thr, 0, p);
 
   EXPECT_EQ(alloc0, __sanitizer_get_current_allocated_bytes());
   EXPECT_GE(__sanitizer_get_heap_size(), heap0);
   EXPECT_EQ(free0, __sanitizer_get_free_bytes());
   EXPECT_EQ(unmapped0, __sanitizer_get_unmapped_bytes());
 }
 
-TEST(Mman, CallocOverflow) {
-#if SANITIZER_DEBUG
-  // EXPECT_DEATH clones a thread with 4K stack,
-  // which is overflown by tsan memory accesses functions in debug mode.
-  return;
-#endif
+TEST(Mman, Valloc) {
+  ThreadState *thr = cur_thread();
+
+  void *p = user_valloc(thr, 0, 100);
+  EXPECT_NE(p, (void*)0);
+  user_free(thr, 0, p);
+
+  p = user_pvalloc(thr, 0, 100);
+  EXPECT_NE(p, (void*)0);
+  user_free(thr, 0, p);
+
+  p = user_pvalloc(thr, 0, 0);
+  EXPECT_NE(p, (void*)0);
+  EXPECT_EQ(GetPageSizeCached(), __sanitizer_get_allocated_size(p));
+  user_free(thr, 0, p);
+}
+
+#if !SANITIZER_DEBUG
+
+TEST(Mman, CallocOverflow) {
   ThreadState *thr = cur_thread();
   uptr pc = 0;
   size_t kArraySize = 4096;
   volatile size_t kMaxSizeT = std::numeric_limits<size_t>::max();
   volatile size_t kArraySize2 = kMaxSizeT / kArraySize + 10;
   volatile void *p = NULL;
   EXPECT_DEATH(p = user_calloc(thr, pc, kArraySize, kArraySize2),
                "allocator is terminating the process instead of returning 0");
   EXPECT_EQ(0L, p);
 }
 
+TEST(Mman, Memalign) {
+  ThreadState *thr = cur_thread();
+
+  void *p = user_memalign(thr, 0, 8, 100);
+  EXPECT_NE(p, (void*)0);
+  user_free(thr, 0, p);
+
+  p = NULL;
+  EXPECT_DEATH(p = user_memalign(thr, 0, 7, 100),
+               "allocator is terminating the process instead of returning 0");
+  EXPECT_EQ(0L, p);
+}
+
+TEST(Mman, PosixMemalign) {
+  ThreadState *thr = cur_thread();
+
+  void *p = NULL;
+  int res = user_posix_memalign(thr, 0, &p, 8, 100);
+  EXPECT_NE(p, (void*)0);
+  EXPECT_EQ(res, 0);
+  user_free(thr, 0, p);
+
+  p = NULL;
+  // Alignment is not a power of two, although is a multiple of sizeof(void*).
+  EXPECT_DEATH(res = user_posix_memalign(thr, 0, &p, 3 * sizeof(p), 100),
+               "allocator is terminating the process instead of returning 0");
+  EXPECT_EQ(0L, p);
+  // Alignment is not a multiple of sizeof(void*), although is a power of 2.
+  EXPECT_DEATH(res = user_posix_memalign(thr, 0, &p, 2, 100),
+               "allocator is terminating the process instead of returning 0");
+  EXPECT_EQ(0L, p);
+}
+
+TEST(Mman, AlignedAlloc) {
+  ThreadState *thr = cur_thread();
+
+  void *p = user_aligned_alloc(thr, 0, 8, 64);
+  EXPECT_NE(p, (void*)0);
+  user_free(thr, 0, p);
+
+  p = NULL;
+  // Alignement is not a power of 2.
+  EXPECT_DEATH(p = user_aligned_alloc(thr, 0, 7, 100),
+               "allocator is terminating the process instead of returning 0");
+  EXPECT_EQ(0L, p);
+  // Size is not a multiple of alignment.
+  EXPECT_DEATH(p = user_aligned_alloc(thr, 0, 8, 100),
+               "allocator is terminating the process instead of returning 0");
+  EXPECT_EQ(0L, p);
+}
+
+#endif
+
 }  // namespace __tsan

test/tsan/allocator_returns_null.cc

 // RUN: %env_tsan_opts=allocator_may_return_null=1 not %run %t new 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=CHECK-nCRASH
 // RUN: %env_tsan_opts=allocator_may_return_null=0 not %run %t new-nothrow 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=CHECK-nnCRASH
 // RUN: %env_tsan_opts=allocator_may_return_null=1     %run %t new-nothrow 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=CHECK-nnNULL
 
 #include <assert.h>
-#include <string.h>
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <limits>
 #include <new>
 
 int main(int argc, char **argv) {
   // Disable stderr buffering. Needed on Windows.
   setvbuf(stderr, NULL, _IONBF, 0);
 
   assert(argc == 2);
   const char *action = argv[1];
   fprintf(stderr, "%s:\n", action);
 
+  // The limit enforced in tsan_mman.cc, user_alloc_internal function.
   static const size_t kMaxAllowedMallocSizePlusOne = (1ULL << 40) + 1;
 
   void *x = 0;
   if (!strcmp(action, "malloc")) {
     x = malloc(kMaxAllowedMallocSizePlusOne);
   } else if (!strcmp(action, "calloc")) {
     x = calloc((kMaxAllowedMallocSizePlusOne / 4) + 1, 4);
   } else if (!strcmp(action, "calloc-overflow")) {
int main(int argc, char **argv) {
   } else if (!strcmp(action, "new")) {
     x = operator new(kMaxAllowedMallocSizePlusOne);
   } else if (!strcmp(action, "new-nothrow")) {
     x = operator new(kMaxAllowedMallocSizePlusOne, std::nothrow);
   } else {
     assert(0);
   }
 
+  fprintf(stderr, "errno: %d\n", errno);
+
   // The NULL pointer is printed differently on different systems, while (long)0
   // is always the same.
   fprintf(stderr, "x: %lx\n", (long)x);
   free(x);
+
   return x != 0;
 }
 
 // CHECK-mCRASH: malloc:
 // CHECK-mCRASH: ThreadSanitizer's allocator is terminating the process
 // CHECK-cCRASH: calloc:
 // CHECK-cCRASH: ThreadSanitizer's allocator is terminating the process
 // CHECK-coCRASH: calloc-overflow:
 // CHECK-coCRASH: ThreadSanitizer's allocator is terminating the process
 // CHECK-rCRASH: realloc:
 // CHECK-rCRASH: ThreadSanitizer's allocator is terminating the process
 // CHECK-mrCRASH: realloc-after-malloc:
 // CHECK-mrCRASH: ThreadSanitizer's allocator is terminating the process
 // CHECK-nCRASH: new:
 // CHECK-nCRASH: ThreadSanitizer's allocator is terminating the process
 // CHECK-nnCRASH: new-nothrow:
 // CHECK-nnCRASH: ThreadSanitizer's allocator is terminating the process
 
 // CHECK-mNULL: malloc:
+// CHECK-mNULL: errno: 12
 // CHECK-mNULL: x: 0
 // CHECK-cNULL: calloc:
+// CHECK-cNULL: errno: 12
 // CHECK-cNULL: x: 0
 // CHECK-coNULL: calloc-overflow:
+// CHECK-coNULL: errno: 12
 // CHECK-coNULL: x: 0
 // CHECK-rNULL: realloc:
+// CHECK-rNULL: errno: 12
 // CHECK-rNULL: x: 0
 // CHECK-mrNULL: realloc-after-malloc:
+// CHECK-mrNULL: errno: 12
 // CHECK-mrNULL: x: 0
 // CHECK-nnNULL: new-nothrow:
 // CHECK-nnNULL: x: 0