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Fix deadlock in timer_delete.

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If the callback function for a timer did a timer_delete, the function
would never return. The problem was that the timer_delete function would try
to wait until the timer thread has finished. Waiting for yourself to finish
doesn't work very well.

Bug: 13397340
Change-Id: Ica123a5bafbc8660c8a4a909e5c2dead55ca429d
This commit is contained in:
Christopher Ferris
2014-03-20 20:47:45 -07:00
parent 2cc58603d5
commit 753ad778bc
2 changed files with 54 additions and 5 deletions
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46
tests/time_test.cpp
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@@ -341,3 +341,49 @@ TEST(time, timer_create_multiple) {
EXPECT_EQ(1, counter2.value);
EXPECT_EQ(0, counter3.value);
}
struct TimerDeleteData {
timer_t timer_id;
pthread_t thread_id;
volatile bool complete;
};
static void TimerDeleteCallback(sigval_t value) {
TimerDeleteData* tdd = reinterpret_cast<TimerDeleteData*>(value.sival_ptr);
tdd->thread_id = pthread_self();
timer_delete(tdd->timer_id);
tdd->complete = true;
}
TEST(time, timer_delete_from_timer_thread) {
TimerDeleteData tdd;
sigevent_t se;
memset(&se, 0, sizeof(se));
se.sigev_notify = SIGEV_THREAD;
se.sigev_notify_function = TimerDeleteCallback;
se.sigev_value.sival_ptr = &tdd;
tdd.complete = false;
ASSERT_EQ(0, timer_create(CLOCK_REALTIME, &se, &tdd.timer_id));
itimerspec ts;
ts.it_value.tv_sec = 0;
ts.it_value.tv_nsec = 100;
ts.it_interval.tv_sec = 0;
ts.it_interval.tv_nsec = 0;
ASSERT_EQ(0, timer_settime(tdd.timer_id, TIMER_ABSTIME, &ts, NULL));
time_t cur_time = time(NULL);
while (!tdd.complete && (time(NULL) - cur_time) < 5);
ASSERT_TRUE(tdd.complete);
#if defined(__BIONIC__)
// Since bionic timers are implemented by creating a thread to handle the
// callback, verify that the thread actually completes.
cur_time = time(NULL);
while (pthread_detach(tdd.thread_id) != ESRCH && (time(NULL) - cur_time) < 5);
ASSERT_EQ(ESRCH, pthread_detach(tdd.thread_id));
#endif
}