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Fix potential race condition on CTS TC pthread_gettid_np

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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
(cherry picked from commit 4f80102935)
This commit is contained in:
Junjie Hu 2015-11-11 12:52:25 +08:00 committed by Elliott Hughes
parent 6209b99a73
commit de1246202a
1 changed files with 7 additions and 0 deletions
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7
tests/pthread_test.cpp Normal file → Executable file
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@ -1303,8 +1303,11 @@ 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
@ -1315,11 +1318,15 @@ 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