From 4f8010293506d4e08d184e66bf4af44ef3483611 Mon Sep 17 00:00:00 2001 From: Junjie Hu Date: Wed, 11 Nov 2015 12:52:25 +0800 Subject: [PATCH] Fix potential race condition on CTS TC pthread_gettid_np 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 Change-Id: I22411f1b0f7446d76a0373cef4ccec858fac7018 --- tests/pthread_test.cpp | 7 +++++++ 1 file changed, 7 insertions(+) mode change 100644 => 100755 tests/pthread_test.cpp diff --git a/tests/pthread_test.cpp b/tests/pthread_test.cpp old mode 100644 new mode 100755 index 8ae28d81e..f15cdabf6 --- a/tests/pthread_test.cpp +++ b/tests/pthread_test.cpp @@ -1244,8 +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(arg) = gettid(); + pthread_mutex_unlock(&gettid_mutex); return NULL; } #endif @@ -1256,11 +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