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author | msg555 <msg555@gmail.com> | 2013-06-06 14:59:28 -0400 |
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committer | Elliott Hughes <enh@google.com> | 2013-06-12 17:30:58 -0700 |
commit | 0f020d18b138e24b1fe34074808e07ac412f35a4 (patch) | |
tree | 75e84d43c82a0e8013d7b1c34d4da1fec64e116c /tests/pthread_test.cpp | |
parent | 6a44d2271f372d0c65b05a5d3377bd00ce92824e (diff) | |
download | android_bionic-0f020d18b138e24b1fe34074808e07ac412f35a4.tar.gz android_bionic-0f020d18b138e24b1fe34074808e07ac412f35a4.tar.bz2 android_bionic-0f020d18b138e24b1fe34074808e07ac412f35a4.zip |
Handles spurious wake-ups in pthread_join()
Removed 'join_count' from pthread_internal_t and switched to using the flag
PTHREAD_ATTR_FLAG_JOINED to indicate if a thread is being joined. Combined with
a switch to a while loop in pthread_join, this fixes spurious wake-ups but
prevents a thread from being joined multiple times. This is fine for
two reasons:
1) The pthread_join specification allows for undefined behavior when multiple
threads try to join a single thread.
2) There is no thread safe way to allow multiple threads to join a single
thread with the pthread interface. The second thread calling pthread_join
could be pre-empted until the thread is destroyed and its handle reused for
a different thread. Therefore multi-join is always an error.
Bug: https://code.google.com/p/android/issues/detail?id=52255
Change-Id: I8b6784d47620ffdcdbfb14524e7402e21d46c5f7
Diffstat (limited to 'tests/pthread_test.cpp')
-rw-r--r-- | tests/pthread_test.cpp | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/tests/pthread_test.cpp b/tests/pthread_test.cpp index a86cadc6b..d754312f9 100644 --- a/tests/pthread_test.cpp +++ b/tests/pthread_test.cpp @@ -317,3 +317,25 @@ TEST(pthread, pthread_kill__no_such_thread) { ASSERT_EQ(ESRCH, pthread_kill(dead_thread, 0)); } + +TEST(pthread, pthread_join__multijoin) { + bool done = false; + + pthread_t t1; + ASSERT_EQ(0, pthread_create(&t1, NULL, SpinFn, &done)); + + pthread_t t2; + ASSERT_EQ(0, pthread_create(&t2, NULL, JoinFn, reinterpret_cast<void*>(t1))); + + sleep(1); // (Give t2 a chance to call pthread_join.) + + // Multiple joins to the same thread should fail. + ASSERT_EQ(EINVAL, pthread_join(t1, NULL)); + + done = true; + + // ...but t2's join on t1 still goes ahead (which we can tell because our join on t2 finishes). + void* join_result; + ASSERT_EQ(0, pthread_join(t2, &join_result)); + ASSERT_EQ(0, reinterpret_cast<int>(join_result)); +} |