Merge "Fix potential race condition on CTS TC pthread_gettid_np" into marshmallow-cts-dev

Root cause:
If start_routine thread exits before pthread_gettid_np is invokded, the "tid" field
will be cleared so that pthread_gettid_np will get "0" (which is cleared by kernel, 
due to the flag "CLONE_CHILD_CLEARTID" is set while calling clone system call inside
pthread_create).

Proposed patch:
Use a mutex to guarantee pthread_gettid_np will be invoked and returned before the
start_routine exits

Signed-off-by: Junjie Hu <junjie.hu@mediatek.com>

Change-Id: I22411f1b0f7446d76a0373cef4ccec858fac7018

libc/bionic/pthread_internal.h

@@ -130,13 +130,8 @@ __LIBC_HIDDEN__ void pthread_key_clean_all(void);
  */
 #define PTHREAD_STACK_SIZE_DEFAULT ((1 * 1024 * 1024) - SIGSTKSZ)
 
-// Leave room for a guard page in the internally created signal stacks.
-#if defined(__LP64__)
-// SIGSTKSZ is not big enough for 64-bit arch. See http://b/23041777.
-#define SIGNAL_STACK_SIZE (16 * 1024 + PAGE_SIZE)
-#else
+/* Leave room for a guard page in the internally created signal stacks. */
 #define SIGNAL_STACK_SIZE (SIGSTKSZ + PAGE_SIZE)
-#endif
 
 /* Needed by fork. */
 __LIBC_HIDDEN__ extern void __bionic_atfork_run_prepare();

tests/Android.mk

@@ -241,7 +241,12 @@ libBionicCtsGtestMain_src_files := gtest_main.cpp
 
 libBionicCtsGtestMain_cflags := $(test_cflags)
 
-libBionicCtsGtestMain_cppflags := $(test_cppflags) -DUSING_GTEST_OUTPUT_FORMAT
+libBionicCtsGtestMain_cppflags := $(test_cppflags) -DUSING_GTEST_OUTPUT_FORMAT \
+
+# Temporarily fix the job count to 1 for CTS since on some devices the
+# number of online cores is incorrectly read as the total number of cores
+# in the system. When b/24376925 is fixed, this should be removed.
+libBionicCtsGtestMain_cppflags += -DJOB_COUNT_FIXED=1
 
 module := libBionicCtsGtestMain
 module_tag := optional

tests/gtest_main.cpp

@@ -59,7 +59,7 @@ using testing::internal::COLOR_GREEN;
 using testing::internal::COLOR_YELLOW;
 using testing::internal::ColoredPrintf;
 
-constexpr int DEFAULT_GLOBAL_TEST_RUN_DEADLINE_MS = 60000;
+constexpr int DEFAULT_GLOBAL_TEST_RUN_DEADLINE_MS = 90000;
 constexpr int DEFAULT_GLOBAL_TEST_RUN_WARNLINE_MS = 2000;
 
 // The time each test can run before killed for the reason of timeout.
@@ -839,8 +839,12 @@ static bool RunTestInSeparateProc(int argc, char** argv, std::vector<TestCase>&
   return all_tests_passed;
 }
 
-static size_t GetProcessorCount() {
+static size_t GetDefaultJobCount() {
+#if defined(JOB_COUNT_FIXED)
+  return JOB_COUNT_FIXED;
+#else
   return static_cast<size_t>(sysconf(_SC_NPROCESSORS_ONLN));
+#endif
 }
 
 static void AddPathSeparatorInTestProgramPath(std::vector<char*>& args) {
@@ -950,7 +954,7 @@ static bool PickOptions(std::vector<char*>& args, IsolationTestOptions& options)
   }
 
   // Init default isolation test options.
-  options.job_count = GetProcessorCount();
+  options.job_count = GetDefaultJobCount();
   options.test_deadline_ms = DEFAULT_GLOBAL_TEST_RUN_DEADLINE_MS;
   options.test_warnline_ms = DEFAULT_GLOBAL_TEST_RUN_WARNLINE_MS;
   options.gtest_color = testing::GTEST_FLAG(color);

tests/pthread_test.cpp

@@ -27,7 +27,6 @@
 #include <sys/syscall.h>
 #include <time.h>
 #include <unistd.h>
-#include <unwind.h>
 
 #include <atomic>
 #include <regex>
@@ -1245,8 +1244,11 @@ TEST(pthread, pthread_attr_getstack_18908062) {
 }
 
 #if defined(__BIONIC__)
+static pthread_mutex_t gettid_mutex;
 static void* pthread_gettid_np_helper(void* arg) {
+  pthread_mutex_lock(&gettid_mutex);
   *reinterpret_cast<pid_t*>(arg) = gettid();
+  pthread_mutex_unlock(&gettid_mutex);
   return NULL;
 }
 #endif
@@ -1257,11 +1259,15 @@ TEST(pthread, pthread_gettid_np) {
 
   pid_t t_gettid_result;
   pthread_t t;
+  pthread_mutex_init(&gettid_mutex, NULL);
+  pthread_mutex_lock(&gettid_mutex);
   pthread_create(&t, NULL, pthread_gettid_np_helper, &t_gettid_result);
 
   pid_t t_pthread_gettid_np_result = pthread_gettid_np(t);
+  pthread_mutex_unlock(&gettid_mutex);
 
   pthread_join(t, NULL);
+  pthread_mutex_destroy(&gettid_mutex);
 
   ASSERT_EQ(t_gettid_result, t_pthread_gettid_np_result);
 #else
@@ -1572,26 +1578,3 @@ TEST_F(pthread_DeathTest, pthread_mutex_unlock_null_64) {
   GTEST_LOG_(INFO) << "This test tests bionic implementation details on 64 bit devices.";
 #endif
 }
-
-extern _Unwind_Reason_Code FrameCounter(_Unwind_Context* ctx, void* arg);
-
-static volatile bool signal_handler_on_altstack_done;
-
-static void SignalHandlerOnAltStack(int signo, siginfo_t*, void*) {
-  ASSERT_EQ(SIGUSR1, signo);
-  // Check if we have enough stack space for unwinding.
-  int count = 0;
-  _Unwind_Backtrace(FrameCounter, &count);
-  ASSERT_GT(count, 0);
-  // Check if we have enough stack space for logging.
-  std::string s(2048, '*');
-  GTEST_LOG_(INFO) << s;
-  signal_handler_on_altstack_done = true;
-}
-
-TEST(pthread, big_enough_signal_stack_for_64bit_arch) {
-  signal_handler_on_altstack_done = false;
-  ScopedSignalHandler handler(SIGUSR1, SignalHandlerOnAltStack, SA_SIGINFO | SA_ONSTACK);
-  kill(getpid(), SIGUSR1);
-  ASSERT_TRUE(signal_handler_on_altstack_done);
-}

tests/stack_unwinding_test.cpp

@@ -34,7 +34,7 @@
 #define noinline __attribute__((__noinline__))
 #define __unused __attribute__((__unused__))
 
-_Unwind_Reason_Code FrameCounter(_Unwind_Context* ctx __unused, void* arg) {
+static _Unwind_Reason_Code FrameCounter(_Unwind_Context* ctx __unused, void* arg) {
   int* count_ptr = reinterpret_cast<int*>(arg);
 
 #if SHOW_FRAME_LOCATIONS