imprecise mark and sweep native memory leak detector

libmemunreachable uses an imprecise mark and sweep pass over all memory
allocated by jemalloc in order to find unreachable allocations.

Change-Id: Ia70bbf31f5b40ff71dab28cfd6cd06c5ef01a2d4

4 files changed, 987 insertions, 0 deletions

diff --git a/libmemunreachable/tests/Allocator_test.cpp b/libmemunreachable/tests/Allocator_test.cpp
new file mode 100644
index 000000000..d8e473eba
--- /dev/null
+++ b/libmemunreachable/tests/Allocator_test.cpp
@@ -0,0 +1,273 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <Allocator.h>
+#include <sys/time.h>
+
+#include <chrono>
+#include <functional>
+#include <list>
+#include <vector>
+
+#include <gtest/gtest.h>
+#include <ScopedDisableMalloc.h>
+
+
+std::function<void()> ScopedAlarm::func_;
+
+using namespace std::chrono_literals;
+
+class AllocatorTest : public testing::Test {
+ protected:
+  AllocatorTest() : heap(), disable_malloc_() {}
+  virtual void SetUp() {
+    heap_count = 0;
+  }
+  virtual void TearDown() {
+    ASSERT_EQ(heap_count, 0);
+    ASSERT_TRUE(heap.empty());
+    ASSERT_FALSE(disable_malloc_.timed_out());
+  }
+  Heap heap;
+ private:
+  ScopedDisableMallocTimeout disable_malloc_;
+};
+
+TEST_F(AllocatorTest, simple) {
+  Allocator<char[100]> allocator(heap);
+  void *ptr = allocator.allocate();
+  ASSERT_TRUE(ptr != NULL);
+  allocator.deallocate(ptr);
+}
+
+TEST_F(AllocatorTest, multiple) {
+  Allocator<char[100]> allocator(heap);
+  void *ptr1 = allocator.allocate();
+  ASSERT_TRUE(ptr1 != NULL);
+  void *ptr2 = allocator.allocate();
+  ASSERT_TRUE(ptr2 != NULL);
+  ASSERT_NE(ptr1, ptr2);
+  allocator.deallocate(ptr1);
+  void *ptr3 = allocator.allocate();
+  ASSERT_EQ(ptr1, ptr3);
+  allocator.deallocate(ptr3);
+  allocator.deallocate(ptr2);
+}
+
+TEST_F(AllocatorTest, many) {
+  const int num = 4096;
+  const int size = 128;
+  Allocator<char[size]> allocator(heap);
+  void *ptr[num];
+  for (int i = 0; i < num; i++) {
+    ptr[i] = allocator.allocate();
+    memset(ptr[i], 0xaa, size);
+    *(reinterpret_cast<unsigned char*>(ptr[i])) = i;
+  }
+
+  for (int i = 0; i < num; i++) {
+    for (int j = 0; j < num; j++) {
+      if (i != j) {
+        ASSERT_NE(ptr[i], ptr[j]);
+      }
+    }
+  }
+
+  for (int i = 0; i < num; i++) {
+    ASSERT_EQ(*(reinterpret_cast<unsigned char*>(ptr[i])), i & 0xFF);
+    allocator.deallocate(ptr[i]);
+  }
+}
+
+TEST_F(AllocatorTest, large) {
+  const size_t size = 1024 * 1024;
+  Allocator<char[size]> allocator(heap);
+  void *ptr = allocator.allocate();
+  memset(ptr, 0xaa, size);
+  allocator.deallocate(ptr);
+}
+
+TEST_F(AllocatorTest, many_large) {
+  const int num = 128;
+  const int size = 1024 * 1024;
+  Allocator<char[size]> allocator(heap);
+  void *ptr[num];
+  for (int i = 0; i < num; i++) {
+    ptr[i] = allocator.allocate();
+    memset(ptr[i], 0xaa, size);
+    *(reinterpret_cast<unsigned char*>(ptr[i])) = i;
+  }
+
+  for (int i = 0; i < num; i++) {
+    ASSERT_EQ(*(reinterpret_cast<unsigned char*>(ptr[i])), i & 0xFF);
+    allocator.deallocate(ptr[i]);
+  }
+}
+
+TEST_F(AllocatorTest, copy) {
+  Allocator<char[100]> a(heap);
+  Allocator<char[200]> b = a;
+  Allocator<char[300]> c(b);
+  Allocator<char[100]> d(a);
+  Allocator<char[100]> e(heap);
+
+  ASSERT_EQ(a, b);
+  ASSERT_EQ(a, c);
+  ASSERT_EQ(a, d);
+  ASSERT_EQ(a, e);
+
+  void* ptr1 = a.allocate();
+  void* ptr2 = b.allocate();
+  void* ptr3 = c.allocate();
+  void* ptr4 = d.allocate();
+
+  b.deallocate(ptr1);
+  d.deallocate(ptr2);
+  a.deallocate(ptr3);
+  c.deallocate(ptr4);
+}
+
+TEST_F(AllocatorTest, stl_vector) {
+  auto v = allocator::vector<int>(Allocator<int>(heap));
+  for (int i = 0; i < 1024; i++) {
+    v.push_back(i);
+  }
+  for (int i = 0; i < 1024; i++) {
+    ASSERT_EQ(v[i], i);
+  }
+  v.clear();
+}
+
+TEST_F(AllocatorTest, stl_list) {
+  auto v = allocator::list<int>(Allocator<int>(heap));
+  for (int i = 0; i < 1024; i++) {
+    v.push_back(i);
+  }
+  int i = 0;
+  for (auto iter = v.begin(); iter != v.end(); iter++, i++) {
+    ASSERT_EQ(*iter, i);
+  }
+  v.clear();
+}
+
+TEST_F(AllocatorTest, shared) {
+  Allocator<int> allocator(heap);
+
+  Allocator<int>::shared_ptr ptr = allocator.make_shared(0);
+  {
+    auto ptr2 = ptr;
+  }
+  ASSERT_NE(ptr, nullptr);
+}
+
+TEST_F(AllocatorTest, unique) {
+  Allocator<int> allocator(heap);
+
+  Allocator<int>::unique_ptr ptr = allocator.make_unique(0);
+
+  ASSERT_NE(ptr, nullptr);
+}
+
+class DisableMallocTest : public ::testing::Test {
+ protected:
+  void alarm(std::chrono::microseconds us) {
+    std::chrono::seconds s = std::chrono::duration_cast<std::chrono::seconds>(us);
+    itimerval t = itimerval();
+    t.it_value.tv_sec = s.count();
+    t.it_value.tv_usec = (us - s).count();
+    setitimer(ITIMER_REAL, &t, NULL);
+  }
+};
+
+TEST_F(DisableMallocTest, reenable) {
+  ASSERT_EXIT({
+    alarm(100ms);
+    void *ptr1 = malloc(128);
+    ASSERT_NE(ptr1, nullptr);
+    free(ptr1);
+    {
+      ScopedDisableMalloc disable_malloc;
+    }
+    void *ptr2 = malloc(128);
+    ASSERT_NE(ptr2, nullptr);
+    free(ptr2);
+    _exit(1);
+  }, ::testing::ExitedWithCode(1), "");
+}
+
+TEST_F(DisableMallocTest, deadlock_allocate) {
+  ASSERT_DEATH({
+    void *ptr = malloc(128);
+    ASSERT_NE(ptr, nullptr);
+    free(ptr);
+    {
+      alarm(100ms);
+      ScopedDisableMalloc disable_malloc;
+      void* ptr = malloc(128);
+      ASSERT_NE(ptr, nullptr);
+      free(ptr);
+    }
+  }, "");
+}
+
+TEST_F(DisableMallocTest, deadlock_new) {
+  ASSERT_DEATH({
+    char* ptr = new(char);
+    ASSERT_NE(ptr, nullptr);
+    delete(ptr);
+    {
+      alarm(100ms);
+      ScopedDisableMalloc disable_malloc;
+      char* ptr = new(char);
+      ASSERT_NE(ptr, nullptr);
+      delete(ptr);
+    }
+  }, "");
+}
+
+TEST_F(DisableMallocTest, deadlock_delete) {
+  ASSERT_DEATH({
+    char* ptr = new(char);
+    ASSERT_NE(ptr, nullptr);
+    {
+      alarm(250ms);
+      ScopedDisableMalloc disable_malloc;
+      delete(ptr);
+    }
+  }, "");
+}
+
+TEST_F(DisableMallocTest, deadlock_free) {
+  ASSERT_DEATH({
+    void *ptr = malloc(128);
+    ASSERT_NE(ptr, nullptr);
+    {
+      alarm(100ms);
+      ScopedDisableMalloc disable_malloc;
+      free(ptr);
+    }
+  }, "");
+}
+
+TEST_F(DisableMallocTest, deadlock_fork) {
+  ASSERT_DEATH({
+    {
+      alarm(100ms);
+      ScopedDisableMalloc disable_malloc;
+      fork();
+    }
+  }, "");
+}
diff --git a/libmemunreachable/tests/HeapWalker_test.cpp b/libmemunreachable/tests/HeapWalker_test.cpp
new file mode 100644
index 000000000..9921eb65e
--- /dev/null
+++ b/libmemunreachable/tests/HeapWalker_test.cpp
@@ -0,0 +1,145 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "HeapWalker.h"
+
+#include <gtest/gtest.h>
+#include <ScopedDisableMalloc.h>
+#include "Allocator.h"
+
+class HeapWalkerTest : public ::testing::Test {
+ public:
+  HeapWalkerTest() : disable_malloc_(), heap_() {}
+
+  void TearDown() {
+    ASSERT_TRUE(heap_.empty());
+    if (!HasFailure()) {
+      ASSERT_FALSE(disable_malloc_.timed_out());
+    }
+  }
+
+ protected:
+  ScopedDisableMallocTimeout disable_malloc_;
+  Heap heap_;
+};
+
+TEST_F(HeapWalkerTest, allocation) {
+  HeapWalker heap_walker(heap_);
+  ASSERT_TRUE(heap_walker.Allocation(3, 4));
+  ASSERT_TRUE(heap_walker.Allocation(2, 3));
+  ASSERT_TRUE(heap_walker.Allocation(4, 5));
+  ASSERT_TRUE(heap_walker.Allocation(6, 7));
+  ASSERT_TRUE(heap_walker.Allocation(0, 1));
+}
+
+TEST_F(HeapWalkerTest, overlap) {
+  HeapWalker heap_walker(heap_);
+  ASSERT_TRUE(heap_walker.Allocation(2, 3));
+  ASSERT_TRUE(heap_walker.Allocation(3, 4));
+  ASSERT_FALSE(heap_walker.Allocation(2, 3));
+  ASSERT_FALSE(heap_walker.Allocation(1, 3));
+  ASSERT_FALSE(heap_walker.Allocation(1, 4));
+  ASSERT_FALSE(heap_walker.Allocation(1, 5));
+  ASSERT_FALSE(heap_walker.Allocation(3, 4));
+  ASSERT_FALSE(heap_walker.Allocation(3, 5));
+  ASSERT_TRUE(heap_walker.Allocation(4, 5));
+  ASSERT_TRUE(heap_walker.Allocation(1, 2));
+}
+
+TEST_F(HeapWalkerTest, zero) {
+  HeapWalker heap_walker(heap_);
+  ASSERT_TRUE(heap_walker.Allocation(2, 2));
+  ASSERT_FALSE(heap_walker.Allocation(2, 2));
+  ASSERT_TRUE(heap_walker.Allocation(3, 3));
+  ASSERT_TRUE(heap_walker.Allocation(1, 1));
+  ASSERT_FALSE(heap_walker.Allocation(2, 3));
+}
+
+#define buffer_begin(buffer) reinterpret_cast<uintptr_t>(buffer)
+#define buffer_end(buffer) (reinterpret_cast<uintptr_t>(buffer) + sizeof(buffer))
+
+TEST_F(HeapWalkerTest, leak) {
+  void* buffer1[16]{};
+  char buffer2[16]{};
+  buffer1[0] = &buffer2[0] - sizeof(void*);
+  buffer1[1] = &buffer2[15] + sizeof(void*);
+
+  HeapWalker heap_walker(heap_);
+  heap_walker.Allocation(buffer_begin(buffer2), buffer_end(buffer2));
+
+  allocator::vector<Range> leaked(heap_);
+  size_t num_leaks = 0;
+  size_t leaked_bytes = 0;
+  ASSERT_EQ(true, heap_walker.Leaked(leaked, 100, &num_leaks, &leaked_bytes));
+
+  EXPECT_EQ(1U, num_leaks);
+  EXPECT_EQ(16U, leaked_bytes);
+  ASSERT_EQ(1U, leaked.size());
+  EXPECT_EQ(buffer_begin(buffer2), leaked[0].begin);
+  EXPECT_EQ(buffer_end(buffer2), leaked[0].end);
+}
+
+TEST_F(HeapWalkerTest, live) {
+  const int from_buffer_entries = 4;
+  const int to_buffer_bytes = 16;
+
+  for (int i = 0; i < from_buffer_entries; i++) {
+    for (int j = 0; j < to_buffer_bytes; j++) {
+      void* buffer1[from_buffer_entries]{};
+      char buffer2[to_buffer_bytes]{};
+      buffer1[i] = &buffer2[j];
+
+      HeapWalker heap_walker(heap_);
+      heap_walker.Allocation(buffer_begin(buffer2), buffer_end(buffer2));
+      heap_walker.Root(buffer_begin(buffer1), buffer_end(buffer1));
+
+      allocator::vector<Range> leaked(heap_);
+      size_t num_leaks = SIZE_T_MAX;
+      size_t leaked_bytes = SIZE_T_MAX;
+      ASSERT_EQ(true, heap_walker.Leaked(leaked, 100, &num_leaks, &leaked_bytes));
+
+      EXPECT_EQ(0U, num_leaks);
+      EXPECT_EQ(0U, leaked_bytes);
+      EXPECT_EQ(0U, leaked.size());
+    }
+  }
+}
+
+TEST_F(HeapWalkerTest, unaligned) {
+  const int from_buffer_entries = 4;
+  const int to_buffer_bytes = 16;
+  void* buffer1[from_buffer_entries]{};
+  char buffer2[to_buffer_bytes]{};
+
+  buffer1[1] = &buffer2;
+
+  for (unsigned int i = 0; i < sizeof(uintptr_t); i++) {
+    for (unsigned int j = 0; j < sizeof(uintptr_t); j++) {
+      HeapWalker heap_walker(heap_);
+      heap_walker.Allocation(buffer_begin(buffer2), buffer_end(buffer2));
+      heap_walker.Root(buffer_begin(buffer1) + i, buffer_end(buffer1) - j);
+
+      allocator::vector<Range> leaked(heap_);
+      size_t num_leaks = SIZE_T_MAX;
+      size_t leaked_bytes = SIZE_T_MAX;
+      ASSERT_EQ(true, heap_walker.Leaked(leaked, 100, &num_leaks, &leaked_bytes));
+
+      EXPECT_EQ(0U, num_leaks);
+      EXPECT_EQ(0U, leaked_bytes);
+      EXPECT_EQ(0U, leaked.size());
+    }
+  }
+}
diff --git a/libmemunreachable/tests/MemUnreachable_test.cpp b/libmemunreachable/tests/MemUnreachable_test.cpp
new file mode 100644
index 000000000..0747b12b6
--- /dev/null
+++ b/libmemunreachable/tests/MemUnreachable_test.cpp
@@ -0,0 +1,218 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/prctl.h>
+
+#include <gtest/gtest.h>
+
+#include <memunreachable/memunreachable.h>
+
+void* ptr;
+
+class HiddenPointer {
+ public:
+  HiddenPointer(size_t size = 256) {
+    Set(malloc(size));
+  }
+  ~HiddenPointer() {
+    Free();
+  }
+  void* Get() {
+    return reinterpret_cast<void*>(~ptr_);
+  }
+  void Free() {
+    free(Get());
+    Set(nullptr);
+  }
+ private:
+  void Set(void* ptr) {
+    ptr_ = ~reinterpret_cast<uintptr_t>(ptr);
+  }
+  volatile uintptr_t ptr_;
+};
+
+static void Ref(void* ptr) {
+  write(0, ptr, 0);
+}
+
+TEST(MemunreachableTest, clean) {
+  UnreachableMemoryInfo info;
+
+  ASSERT_TRUE(LogUnreachableMemory(true, 100));
+
+  ASSERT_TRUE(GetUnreachableMemory(info));
+  ASSERT_EQ(0U, info.leaks.size());
+}
+
+TEST(MemunreachableTest, stack) {
+  HiddenPointer hidden_ptr;
+
+  {
+    void* ptr = hidden_ptr.Get();
+    Ref(ptr);
+
+    UnreachableMemoryInfo info;
+
+    ASSERT_TRUE(GetUnreachableMemory(info));
+    ASSERT_EQ(0U, info.leaks.size());
+
+    Ref(ptr);
+  }
+
+  {
+    UnreachableMemoryInfo info;
+
+    ASSERT_TRUE(GetUnreachableMemory(info));
+    ASSERT_EQ(1U, info.leaks.size());
+  }
+
+  hidden_ptr.Free();
+
+  {
+    UnreachableMemoryInfo info;
+
+    ASSERT_TRUE(GetUnreachableMemory(info));
+    ASSERT_EQ(0U, info.leaks.size());
+  }
+}
+
+TEST(MemunreachableTest, global) {
+  HiddenPointer hidden_ptr;
+
+  ptr = hidden_ptr.Get();
+
+  {
+    UnreachableMemoryInfo info;
+
+    ASSERT_TRUE(GetUnreachableMemory(info));
+    ASSERT_EQ(0U, info.leaks.size());
+  }
+
+  ptr = NULL;
+
+  {
+    UnreachableMemoryInfo info;
+
+    ASSERT_TRUE(GetUnreachableMemory(info));
+    ASSERT_EQ(1U, info.leaks.size());
+  }
+
+  hidden_ptr.Free();
+
+  {
+    UnreachableMemoryInfo info;
+
+    ASSERT_TRUE(GetUnreachableMemory(info));
+    ASSERT_EQ(0U, info.leaks.size());
+  }
+}
+
+TEST(MemunreachableTest, tls) {
+  HiddenPointer hidden_ptr;
+  pthread_key_t key;
+  pthread_key_create(&key, NULL);
+
+  pthread_setspecific(key, hidden_ptr.Get());
+
+  {
+    UnreachableMemoryInfo info;
+
+    ASSERT_TRUE(GetUnreachableMemory(info));
+    ASSERT_EQ(0U, info.leaks.size());
+  }
+
+  pthread_setspecific(key, nullptr);
+
+  {
+    UnreachableMemoryInfo info;
+
+    ASSERT_TRUE(GetUnreachableMemory(info));
+    ASSERT_EQ(1U, info.leaks.size());
+  }
+
+  hidden_ptr.Free();
+
+  {
+    UnreachableMemoryInfo info;
+
+    ASSERT_TRUE(GetUnreachableMemory(info));
+    ASSERT_EQ(0U, info.leaks.size());
+  }
+
+  pthread_key_delete(key);
+}
+
+TEST(MemunreachableTest, twice) {
+  HiddenPointer hidden_ptr;
+
+  {
+    UnreachableMemoryInfo info;
+
+    ASSERT_TRUE(GetUnreachableMemory(info));
+    ASSERT_EQ(1U, info.leaks.size());
+  }
+
+  {
+    UnreachableMemoryInfo info;
+
+    ASSERT_TRUE(GetUnreachableMemory(info));
+    ASSERT_EQ(1U, info.leaks.size());
+  }
+
+  hidden_ptr.Free();
+
+  {
+    UnreachableMemoryInfo info;
+
+    ASSERT_TRUE(GetUnreachableMemory(info));
+    ASSERT_EQ(0U, info.leaks.size());
+  }
+}
+
+TEST(MemunreachableTest, log) {
+  HiddenPointer hidden_ptr;
+
+  ASSERT_TRUE(LogUnreachableMemory(true, 100));
+
+  hidden_ptr.Free();
+
+  {
+    UnreachableMemoryInfo info;
+
+    ASSERT_TRUE(GetUnreachableMemory(info));
+    ASSERT_EQ(0U, info.leaks.size());
+  }
+}
+
+TEST(MemunreachableTest, notdumpable) {
+  ASSERT_EQ(0, prctl(PR_SET_DUMPABLE, 0));
+
+  HiddenPointer hidden_ptr;
+
+  ASSERT_TRUE(LogUnreachableMemory(true, 100));
+
+  ASSERT_EQ(0, prctl(PR_SET_DUMPABLE, 1));
+}
+
+TEST(MemunreachableTest, leak_lots) {
+  std::vector<HiddenPointer> hidden_ptrs;
+  hidden_ptrs.resize(1024);
+
+  ASSERT_TRUE(LogUnreachableMemory(true, 100));
+}
diff --git a/libmemunreachable/tests/ThreadCapture_test.cpp b/libmemunreachable/tests/ThreadCapture_test.cpp
new file mode 100644
index 000000000..cefe94e6a
--- /dev/null
+++ b/libmemunreachable/tests/ThreadCapture_test.cpp
@@ -0,0 +1,351 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "ThreadCapture.h"
+
+#include <fcntl.h>
+#include <pthread.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+
+#include <algorithm>
+#include <functional>
+#include <memory>
+#include <thread>
+
+#include <gtest/gtest.h>
+
+#include <android-base/unique_fd.h>
+
+#include "Allocator.h"
+#include "ScopedDisableMalloc.h"
+#include "ScopedPipe.h"
+
+using namespace std::chrono_literals;
+
+class ThreadListTest : public ::testing::TestWithParam<int> {
+ public:
+  ThreadListTest() : stop_(false) {}
+
+  ~ThreadListTest() {
+    // pthread_join may return before the entry in /proc/pid/task/ is gone,
+    // loop until ListThreads only finds the main thread so the next test
+    // doesn't fail.
+    WaitForThreads();
+  }
+
+  virtual void TearDown() {
+    ASSERT_TRUE(heap.empty());
+  }
+
+ protected:
+  template<class Function>
+  void StartThreads(unsigned int threads, Function&& func) {
+    threads_.reserve(threads);
+    tids_.reserve(threads);
+    for (unsigned int i = 0; i < threads; i++) {
+      threads_.emplace_back([&, i, threads, this]() {
+        {
+          std::lock_guard<std::mutex> lk(m_);
+          tids_.push_back(gettid());
+          if (tids_.size() == threads) {
+            cv_start_.notify_one();
+          }
+        }
+
+        func();
+
+        {
+          std::unique_lock<std::mutex> lk(m_);
+          cv_stop_.wait(lk, [&] {return stop_;});
+        }
+      });
+    }
+
+    {
+      std::unique_lock<std::mutex> lk(m_);
+      cv_start_.wait(lk, [&]{ return tids_.size() == threads; });
+    }
+  }
+
+  void StopThreads() {
+    {
+      std::lock_guard<std::mutex> lk(m_);
+      stop_ = true;
+    }
+    cv_stop_.notify_all();
+
+    for (auto i = threads_.begin(); i != threads_.end(); i++) {
+      i->join();
+    }
+    threads_.clear();
+    tids_.clear();
+  }
+
+  std::vector<pid_t>& tids() {
+    return tids_;
+  }
+
+  Heap heap;
+
+ private:
+  void WaitForThreads() {
+    auto tids = TidList{heap};
+    ThreadCapture thread_capture{getpid(), heap};
+
+    for (unsigned int i = 0; i < 100; i++) {
+      EXPECT_TRUE(thread_capture.ListThreads(tids));
+      if (tids.size() == 1) {
+        break;
+      }
+      std::this_thread::sleep_for(10ms);
+    }
+    EXPECT_EQ(1U, tids.size());
+  }
+
+  std::mutex m_;
+  std::condition_variable cv_start_;
+  std::condition_variable cv_stop_;
+  bool stop_;
+  std::vector<pid_t> tids_;
+
+  std::vector<std::thread> threads_;
+};
+
+TEST_F(ThreadListTest, list_one) {
+  ScopedDisableMallocTimeout disable_malloc;
+
+  ThreadCapture thread_capture(getpid(), heap);
+
+  auto expected_tids = allocator::vector<pid_t>(1, getpid(), heap);
+  auto list_tids = allocator::vector<pid_t>(heap);
+
+  ASSERT_TRUE(thread_capture.ListThreads(list_tids));
+
+  ASSERT_EQ(expected_tids, list_tids);
+
+  if (!HasFailure()) {
+    ASSERT_FALSE(disable_malloc.timed_out());
+  }
+}
+
+TEST_P(ThreadListTest, list_some) {
+  const unsigned int threads = GetParam() - 1;
+
+  StartThreads(threads, [](){});
+  std::vector<pid_t> expected_tids = tids();
+  expected_tids.push_back(getpid());
+
+  auto list_tids = allocator::vector<pid_t>(heap);
+
+  {
+    ScopedDisableMallocTimeout disable_malloc;
+
+    ThreadCapture thread_capture(getpid(), heap);
+
+    ASSERT_TRUE(thread_capture.ListThreads(list_tids));
+
+    if (!HasFailure()) {
+      ASSERT_FALSE(disable_malloc.timed_out());
+    }
+  }
+
+  StopThreads();
+
+  std::sort(list_tids.begin(), list_tids.end());
+  std::sort(expected_tids.begin(), expected_tids.end());
+
+  ASSERT_EQ(expected_tids.size(), list_tids.size());
+  EXPECT_TRUE(std::equal(expected_tids.begin(), expected_tids.end(), list_tids.begin()));
+}
+
+INSTANTIATE_TEST_CASE_P(ThreadListTest, ThreadListTest, ::testing::Values(1, 2, 10, 1024));
+
+class ThreadCaptureTest : public ThreadListTest {
+ public:
+  ThreadCaptureTest() {}
+  ~ThreadCaptureTest() {}
+  void Fork(std::function<void()>&& child_init,
+      std::function<void()>&& child_cleanup,
+      std::function<void(pid_t)>&& parent) {
+
+    ScopedPipe start_pipe;
+    ScopedPipe stop_pipe;
+
+    int pid = fork();
+
+    if (pid == 0) {
+      // child
+      child_init();
+      EXPECT_EQ(1, TEMP_FAILURE_RETRY(write(start_pipe.Sender(), "+", 1))) << strerror(errno);
+      char buf;
+      EXPECT_EQ(1, TEMP_FAILURE_RETRY(read(stop_pipe.Receiver(), &buf, 1))) << strerror(errno);
+      child_cleanup();
+      _exit(0);
+    } else {
+      // parent
+      ASSERT_GT(pid, 0);
+      char buf;
+      ASSERT_EQ(1, TEMP_FAILURE_RETRY(read(start_pipe.Receiver(), &buf, 1))) << strerror(errno);
+
+      parent(pid);
+
+      ASSERT_EQ(1, TEMP_FAILURE_RETRY(write(stop_pipe.Sender(), "+", 1))) << strerror(errno);
+      siginfo_t info{};
+      ASSERT_EQ(0, TEMP_FAILURE_RETRY(waitid(P_PID, pid, &info, WEXITED))) << strerror(errno);
+    }
+  }
+};
+
+TEST_P(ThreadCaptureTest, capture_some) {
+  const unsigned int threads = GetParam();
+
+  Fork([&](){
+    // child init
+    StartThreads(threads - 1, [](){});
+  },
+  [&](){
+    // child cleanup
+    StopThreads();
+  },
+  [&](pid_t child){
+    // parent
+    ASSERT_GT(child, 0);
+
+    {
+      ScopedDisableMallocTimeout disable_malloc;
+
+      ThreadCapture thread_capture(child, heap);
+      auto list_tids = allocator::vector<pid_t>(heap);
+
+      ASSERT_TRUE(thread_capture.ListThreads(list_tids));
+      ASSERT_EQ(threads, list_tids.size());
+
+      ASSERT_TRUE(thread_capture.CaptureThreads());
+
+      auto thread_info = allocator::vector<ThreadInfo>(heap);
+      ASSERT_TRUE(thread_capture.CapturedThreadInfo(thread_info));
+      ASSERT_EQ(threads, thread_info.size());
+      ASSERT_TRUE(thread_capture.ReleaseThreads());
+
+      if (!HasFailure()) {
+        ASSERT_FALSE(disable_malloc.timed_out());
+      }
+}
+  });
+}
+
+INSTANTIATE_TEST_CASE_P(ThreadCaptureTest, ThreadCaptureTest, ::testing::Values(1, 2, 10, 1024));
+
+TEST_F(ThreadCaptureTest, capture_kill) {
+  int ret = fork();
+
+  if (ret == 0) {
+    // child
+    sleep(10);
+  } else {
+    // parent
+    ASSERT_GT(ret, 0);
+
+    {
+      ScopedDisableMallocTimeout disable_malloc;
+
+      ThreadCapture thread_capture(ret, heap);
+      thread_capture.InjectTestFunc([&](pid_t tid){
+        syscall(SYS_tgkill, ret, tid, SIGKILL);
+        usleep(10000);
+      });
+      auto list_tids = allocator::vector<pid_t>(heap);
+
+      ASSERT_TRUE(thread_capture.ListThreads(list_tids));
+      ASSERT_EQ(1U, list_tids.size());
+
+      ASSERT_FALSE(thread_capture.CaptureThreads());
+
+      if (!HasFailure()) {
+        ASSERT_FALSE(disable_malloc.timed_out());
+      }
+    }
+  }
+}
+
+TEST_F(ThreadCaptureTest, capture_signal) {
+  const int sig = SIGUSR1;
+
+  ScopedPipe pipe;
+
+  // For signal handler
+  static ScopedPipe* g_pipe;
+
+  Fork([&](){
+    // child init
+    pipe.CloseReceiver();
+
+    g_pipe = &pipe;
+
+    struct sigaction act{};
+    act.sa_handler = [](int){
+      char buf = '+';
+      write(g_pipe->Sender(), &buf, 1);
+      g_pipe->CloseSender();
+    };
+    sigaction(sig, &act, NULL);
+    sigset_t set;
+    sigemptyset(&set);
+    sigaddset(&set, sig);
+    pthread_sigmask(SIG_UNBLOCK, &set, NULL);
+  },
+  [&](){
+    // child cleanup
+    g_pipe = nullptr;
+    pipe.Close();
+  },
+  [&](pid_t child){
+    // parent
+    ASSERT_GT(child, 0);
+    pipe.CloseSender();
+
+    {
+      ScopedDisableMallocTimeout disable_malloc;
+
+      ThreadCapture thread_capture(child, heap);
+      thread_capture.InjectTestFunc([&](pid_t tid){
+        syscall(SYS_tgkill, child, tid, sig);
+        usleep(10000);
+      });
+      auto list_tids = allocator::vector<pid_t>(heap);
+
+      ASSERT_TRUE(thread_capture.ListThreads(list_tids));
+      ASSERT_EQ(1U, list_tids.size());
+
+      ASSERT_TRUE(thread_capture.CaptureThreads());
+
+      auto thread_info = allocator::vector<ThreadInfo>(heap);
+      ASSERT_TRUE(thread_capture.CapturedThreadInfo(thread_info));
+      ASSERT_EQ(1U, thread_info.size());
+      ASSERT_TRUE(thread_capture.ReleaseThreads());
+
+      usleep(100000);
+      char buf;
+      ASSERT_EQ(1, TEMP_FAILURE_RETRY(read(pipe.Receiver(), &buf, 1)));
+      ASSERT_EQ(buf, '+');
+
+      if (!HasFailure()) {
+        ASSERT_FALSE(disable_malloc.timed_out());
+      }
+    }
+  });
+}