Pthread thread deadlock when faketime used

[slobodyanukma@…]

Following code deadlocked on pthread_cond_timedwait call if started like

LD_PRELOAD=/usr/lib/x86_64-linux-gnu/faketime/libfaketime.so.1 FAKETIME="+30d" ./a.out

#include <boost/thread.hpp>
#include <iostream>

using namespace std;

void f() {
	int n=50;
	while (n--) {
		cout << n << endl;
		boost::this_thread::sleep(boost::posix_time::seconds(1));
//		boost::this_thread::sleep_for( boost::chrono::seconds(1) );
//		sleep(1);
	}
}

int main(int argc, char* argv[]) {
	boost::thread th(f);
	th.join();
	return 0;
}

Here is backtarce:

#0  pthread_cond_timedwait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:238
#1  0x0000000000da8ed3 in boost::condition_variable::do_wait_until(boost::unique_lock<boost::mutex>&, timespec const&) ()
#2  0x0000000000da792f in boost::this_thread::hiden::sleep_until(timespec const&) ()
#3  0x0000000000978ff6 in boost::this_thread::sleep (abs_time=...) at /home/sl/project/Elephantdrive/devroot/3rdparty/boost/boost/thread/pthread/thread_data.hpp:249
#4  0x0000000000979065 in boost::this_thread::sleep<boost::posix_time::seconds> (rel_time=...) at /home/sl/project/Elephantdrive/devroot/3rdparty/boost/boost/thread/pthread/thread_data.hpp:255

But no deadlocks if used sleep(1) instead. I belive it is some pthread_cond_timedwait issue but will be good call sleep() or usleep() in boost's internals instead in according points if possible.

[viboes]

Can you use

boost::this_thread::no_interruption_point::sleep_for( boost::chrono::seconds(1) );

which is not interruptible and so don't need the use of cv?

[viboes]

I've a patch that uses pthread_condattr_setclock. I have no platform providing it (I'm using MacOS). The user will need to define BOOST_THREAD_HAS_CONDATTR_SET_CLOCK_MONOTONIC until I find a way to detect it.

can you check if this works for you?

Add to develop branch ​https://github.com/boostorg/thread/commit/9f883f6ad7377b88b79fa70cc5de68cbfb0213e4

[viboes]

​https://github.com/boostorg/thread/commit/730cb550e6d969520c3f39e0ddf5d80351bddf3a