[boost] [asio] Race conditions detected with valgrind drd in example/http/server2

Subject: [boost] [asio] Race conditions detected with valgrind drd in example/http/server2
From: Jorge Moraleda (moraleda_at_[hidden])
Date: 2010-06-04 21:46:27

When testing boost.asio (example/http/server2) for race conditions
using valgrind drd, some
errors are reported right after the first connection to the server is
made. I am using Valgrind-3.6.0.SVN and gcc version 4.4.4 (Debian
4.4.4-4). This is an up to date Debian sid 64 bit system.

To reproduce:

g++ -l boost_thread -l boost_system
/opt/boost/boost/doc/html/boost_asio/example/http/server2/*cpp

valgrind --tool=drd ./a.out 127.0.0.1 31174 8 /tmp

While it is running type "http://localhost:31174/main.cpp" in your
browser (where main.cpp is a file in /tmp). Then several race
conditions occur. These are the valgrind error messages:

==7737== drd, a thread error detector
==7737== Copyright (C) 2006-2010, and GNU GPL'd, by Bart Van Assche.
==7737== Using Valgrind-3.6.0.SVN and LibVEX; rerun with -h for copyright info
==7737== Command: ./a.out 127.0.0.1 31174 8 /tmp
==7737==
==7737== Thread 4:
==7737== Conflicting load by thread 4 at 0x061875f0 size 8
==7737==    at 0x40DB72:
boost::asio::detail::op_queue<boost::asio::detail::reactor_op>::front()
(in /tmp/a.out)
==7737==    by 0x417974: boost::asio::detail::epoll_reactor::run(bool,
boost::asio::detail::op_queue<boost::asio::detail::task_io_service_operation<boost::asio::detail::epoll_reactor>
>&) (in /tmp/a.out)
==7737==    by 0x41C809:
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::do_one(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&,
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::idle_thread_info*)
(in /tmp/a.out)
==7737==    by 0x41A026:
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::run(boost::system::error_code&)
(in /tmp/a.out)
==7737==    by 0x417D26: boost::asio::io_service::run() (in /tmp/a.out)
==7737==    by 0x430358: unsigned long boost::_mfi::mf0<unsigned long,
boost::asio::io_service>::call<boost::shared_ptr<boost::asio::io_service>
>(boost::shared_ptr<boost::asio::io_service>&, void const*) const (in
/tmp/a.out)
==7737==    by 0x42FF74: unsigned long boost::_mfi::mf0<unsigned long,
boost::asio::io_service>::operator()<boost::shared_ptr<boost::asio::io_service>
>(boost::shared_ptr<boost::asio::io_service>&) const (in /tmp/a.out)
==7737==    by 0x42FE1E: unsigned long
boost::_bi::list1<boost::_bi::value<boost::shared_ptr<boost::asio::io_service>
> >::operator()<unsigned long, boost::_mfi::mf0<unsigned long,
boost::asio::io_service>, boost::_bi::list0>(boost::_bi::type<unsigned
long>, boost::_mfi::mf0<unsigned long, boost::asio::io_service>&,
boost::_bi::list0&, long) (in /tmp/a.out)
==7737==    by 0x42FD66: boost::_bi::bind_t<unsigned long,
boost::_mfi::mf0<unsigned long, boost::asio::io_service>,
boost::_bi::list1<boost::_bi::value<boost::shared_ptr<boost::asio::io_service>
> > >::operator()() (in /tmp/a.out)
==7737==    by 0x42EE79:
boost::detail::thread_data<boost::_bi::bind_t<unsigned long,
boost::_mfi::mf0<unsigned long, boost::asio::io_service>,
boost::_bi::list1<boost::_bi::value<boost::shared_ptr<boost::asio::io_service>
> > > >::run() (in /tmp/a.out)
==7737==    by 0x4E41F5F: thread_proxy (in
/usr/local/lib/libboost_thread.so.1.43.0)
==7737==    by 0x4C2EA60: vgDrd_thread_wrapper (drd_pthread_intercepts.c:272)
==7737== Address 0x61875f0 is at offset 80 from 0x61875a0. Allocation context:
==7737==    at 0x4C26FD1: operator new(unsigned long) (vg_replace_malloc.c:261)
==7737==    by 0x43BDC8:
__gnu_cxx::new_allocator<std::_List_node<std::pair<int,
boost::asio::detail::epoll_reactor::descriptor_state> >
>::allocate(unsigned long, void const*) (in /tmp/a.out)
==7737==    by 0x43B72D: std::_List_base<std::pair<int,
boost::asio::detail::epoll_reactor::descriptor_state>,
std::allocator<std::pair<int,
boost::asio::detail::epoll_reactor::descriptor_state> >
>::_M_get_node() (in /tmp/a.out)
==7737==    by 0x43AD64: std::list<std::pair<int,
boost::asio::detail::epoll_reactor::descriptor_state>,
std::allocator<std::pair<int,
boost::asio::detail::epoll_reactor::descriptor_state> >
>::_M_create_node(std::pair<int,
boost::asio::detail::epoll_reactor::descriptor_state> const&) (in
/tmp/a.out)
==7737==    by 0x43A0FC: std::list<std::pair<int,
boost::asio::detail::epoll_reactor::descriptor_state>,
std::allocator<std::pair<int,
boost::asio::detail::epoll_reactor::descriptor_state> >
>::insert(std::_List_iterator<std::pair<int,
boost::asio::detail::epoll_reactor::descriptor_state> >,
std::pair<int, boost::asio::detail::epoll_reactor::descriptor_state>
const&) (in /tmp/a.out)
==7737==    by 0x439A77: boost::asio::detail::hash_map<int,
boost::asio::detail::epoll_reactor::descriptor_state>::values_insert(std::_List_iterator<std::pair<int,
boost::asio::detail::epoll_reactor::descriptor_state> >,
std::pair<int, boost::asio::detail::epoll_reactor::descriptor_state>
const&) (in /tmp/a.out)
==7737==    by 0x438B60: boost::asio::detail::hash_map<int,
boost::asio::detail::epoll_reactor::descriptor_state>::insert(std::pair<int,
boost::asio::detail::epoll_reactor::descriptor_state> const&) (in
/tmp/a.out)
==7737==    by 0x43811B:
boost::asio::detail::epoll_reactor::register_descriptor(int,
boost::asio::detail::epoll_reactor::descriptor_state*&) (in
/tmp/a.out)
==7737==    by 0x43DE25:
boost::asio::detail::reactive_socket_service<boost::asio::ip::tcp>::assign(boost::asio::detail::reactive_socket_service<boost::asio::ip::tcp>::implementation_type&,
boost::asio::ip::tcp const&, int const&, boost::system::error_code&)
(in /tmp/a.out)
==7737==    by 0x43D954:
boost::asio::stream_socket_service<boost::asio::ip::tcp>::assign(boost::asio::detail::reactive_socket_service<boost::asio::ip::tcp>::implementation_type&,
boost::asio::ip::tcp const&, int const&, boost::system::error_code&)
(in /tmp/a.out)
==7737==    by 0x43D689:
boost::asio::basic_socket<boost::asio::ip::tcp,
boost::asio::stream_socket_service<boost::asio::ip::tcp>
>::assign(boost::asio::ip::tcp const&, int const&,
boost::system::error_code&) (in /tmp/a.out)
==7737==    by 0x43D274:
boost::asio::detail::reactive_socket_service<boost::asio::ip::tcp>::accept_op_base<boost::asio::basic_socket<boost::asio::ip::tcp,
boost::asio::stream_socket_service<boost::asio::ip::tcp> >
>::do_perform(boost::asio::detail::reactor_op*) (in /tmp/a.out)
==7737== Other segment start (thread 3)
==7737==    at 0x4C2F283: pthread_mutex_lock (drd_pthread_intercepts.c:578)
==7737==    by 0x40AC2B: boost::asio::detail::posix_mutex::lock() (in
/tmp/a.out)
==7737==    by 0x40D4CF:
boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>::scoped_lock(boost::asio::detail::posix_mutex&)
(in /tmp/a.out)
==7737==    by 0x4380D4:
boost::asio::detail::epoll_reactor::register_descriptor(int,
boost::asio::detail::epoll_reactor::descriptor_state*&) (in
/tmp/a.out)
==7737==    by 0x43DE25:
boost::asio::detail::reactive_socket_service<boost::asio::ip::tcp>::assign(boost::asio::detail::reactive_socket_service<boost::asio::ip::tcp>::implementation_type&,
boost::asio::ip::tcp const&, int const&, boost::system::error_code&)
(in /tmp/a.out)
==7737==    by 0x43D954:
boost::asio::stream_socket_service<boost::asio::ip::tcp>::assign(boost::asio::detail::reactive_socket_service<boost::asio::ip::tcp>::implementation_type&,
boost::asio::ip::tcp const&, int const&, boost::system::error_code&)
(in /tmp/a.out)
==7737==    by 0x43D689:
boost::asio::basic_socket<boost::asio::ip::tcp,
boost::asio::stream_socket_service<boost::asio::ip::tcp>
>::assign(boost::asio::ip::tcp const&, int const&,
boost::system::error_code&) (in /tmp/a.out)
==7737==    by 0x43D274:
boost::asio::detail::reactive_socket_service<boost::asio::ip::tcp>::accept_op_base<boost::asio::basic_socket<boost::asio::ip::tcp,
boost::asio::stream_socket_service<boost::asio::ip::tcp> >
>::do_perform(boost::asio::detail::reactor_op*) (in /tmp/a.out)
==7737==    by 0x40AF7A: boost::asio::detail::reactor_op::perform()
(in /tmp/a.out)
==7737==    by 0x41798B: boost::asio::detail::epoll_reactor::run(bool,
boost::asio::detail::op_queue<boost::asio::detail::task_io_service_operation<boost::asio::detail::epoll_reactor>
>&) (in /tmp/a.out)
==7737==    by 0x41C809:
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::do_one(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&,
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::idle_thread_info*)
(in /tmp/a.out)
==7737==    by 0x41A026:
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::run(boost::system::error_code&)
(in /tmp/a.out)
==7737== Other segment end (thread 3)
==7737==    at 0x4C2FE7F: pthread_mutex_unlock (drd_pthread_intercepts.c:631)
==7737==    by 0x40AC45: boost::asio::detail::posix_mutex::unlock()
(in /tmp/a.out)
==7737==    by 0x40D500:
boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>::~scoped_lock()
(in /tmp/a.out)
==7737==    by 0x438273:
boost::asio::detail::epoll_reactor::register_descriptor(int,
boost::asio::detail::epoll_reactor::descriptor_state*&) (in
/tmp/a.out)
==7737==    by 0x43DE25:
boost::asio::detail::reactive_socket_service<boost::asio::ip::tcp>::assign(boost::asio::detail::reactive_socket_service<boost::asio::ip::tcp>::implementation_type&,
boost::asio::ip::tcp const&, int const&, boost::system::error_code&)
(in /tmp/a.out)
==7737==    by 0x43D954:
boost::asio::stream_socket_service<boost::asio::ip::tcp>::assign(boost::asio::detail::reactive_socket_service<boost::asio::ip::tcp>::implementation_type&,
boost::asio::ip::tcp const&, int const&, boost::system::error_code&)
(in /tmp/a.out)
==7737==    by 0x43D689:
boost::asio::basic_socket<boost::asio::ip::tcp,
boost::asio::stream_socket_service<boost::asio::ip::tcp>
>::assign(boost::asio::ip::tcp const&, int const&,
boost::system::error_code&) (in /tmp/a.out)
==7737==    by 0x43D274:
boost::asio::detail::reactive_socket_service<boost::asio::ip::tcp>::accept_op_base<boost::asio::basic_socket<boost::asio::ip::tcp,
boost::asio::stream_socket_service<boost::asio::ip::tcp> >
>::do_perform(boost::asio::detail::reactor_op*) (in /tmp/a.out)
==7737==    by 0x40AF7A: boost::asio::detail::reactor_op::perform()
(in /tmp/a.out)
==7737==    by 0x41798B: boost::asio::detail::epoll_reactor::run(bool,
boost::asio::detail::op_queue<boost::asio::detail::task_io_service_operation<boost::asio::detail::epoll_reactor>
>&) (in /tmp/a.out)
==7737==    by 0x41C809:
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::do_one(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&,
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::idle_thread_info*)
(in /tmp/a.out)
==7737==    by 0x41A026:
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::run(boost::system::error_code&)
(in /tmp/a.out)
==7737==
==7737== Thread 3:
==7737== Probably a race condition: condition variable 0x8583c40 has
been signaled but the associated mutex 0x61820f8 is not locked by the
signalling thread.
==7737==    at 0x4C283F9: pthread_cond_signal@* (drd_pthread_intercepts.c:736)
==7737==    by 0x4119FE: void
boost::asio::detail::posix_event::signal_and_unlock<boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>
>(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&)
(in /tmp/a.out)
==7737==    by 0x4108F2:
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::wake_one_idle_thread_and_unlock(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&)
(in /tmp/a.out)
==7737==    by 0x40F1C2:
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::wake_one_thread_and_unlock(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&)
(in /tmp/a.out)
==7737==    by 0x40DA56:
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::init_task()
(in /tmp/a.out)
==7737==    by 0x40B941:
boost::asio::detail::epoll_reactor::init_task() (in /tmp/a.out)
==7737==    by 0x4148D8:
boost::asio::detail::reactive_socket_service<boost::asio::ip::tcp>::reactive_socket_service(boost::asio::io_service&)
(in /tmp/a.out)
==7737==    by 0x414035:
boost::asio::stream_socket_service<boost::asio::ip::tcp>::stream_socket_service(boost::asio::io_service&)
(in /tmp/a.out)
==7737==    by 0x413893: boost::asio::io_service::service*
boost::asio::detail::service_registry::create<boost::asio::stream_socket_service<boost::asio::ip::tcp>
>(boost::asio::io_service&) (in /tmp/a.out)
==7737==    by 0x40ADB8:
boost::asio::detail::service_registry::do_use_service(boost::asio::io_service::service::key
const&, boost::asio::io_service::service*
(*)(boost::asio::io_service&)) (in /tmp/a.out)
==7737==    by 0x412B7E:
boost::asio::stream_socket_service<boost::asio::ip::tcp>&
boost::asio::detail::service_registry::use_service<boost::asio::stream_socket_service<boost::asio::ip::tcp>
>() (in /tmp/a.out)
==7737==    by 0x411B3A:
boost::asio::stream_socket_service<boost::asio::ip::tcp>&
boost::asio::use_service<boost::asio::stream_socket_service<boost::asio::ip::tcp>
>(boost::asio::io_service&) (in /tmp/a.out)
==7737== cond 0x8583c40 was first observed at:
==7737==    at 0x4C27C59: pthread_cond_init@* (drd_pthread_intercepts.c:652)
==7737==    by 0x417573:
boost::asio::detail::posix_event::posix_event() (in /tmp/a.out)
==7737==    by 0x419F07:
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::idle_thread_info::idle_thread_info()
(in /tmp/a.out)
==7737==    by 0x419FBC:
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::run(boost::system::error_code&)
(in /tmp/a.out)
==7737==    by 0x417D26: boost::asio::io_service::run() (in /tmp/a.out)
==7737==    by 0x430358: unsigned long boost::_mfi::mf0<unsigned long,
boost::asio::io_service>::call<boost::shared_ptr<boost::asio::io_service>
>(boost::shared_ptr<boost::asio::io_service>&, void const*) const (in
/tmp/a.out)
==7737==    by 0x42FF74: unsigned long boost::_mfi::mf0<unsigned long,
boost::asio::io_service>::operator()<boost::shared_ptr<boost::asio::io_service>
>(boost::shared_ptr<boost::asio::io_service>&) const (in /tmp/a.out)
==7737==    by 0x42FE1E: unsigned long
boost::_bi::list1<boost::_bi::value<boost::shared_ptr<boost::asio::io_service>
> >::operator()<unsigned long, boost::_mfi::mf0<unsigned long,
boost::asio::io_service>, boost::_bi::list0>(boost::_bi::type<unsigned
long>, boost::_mfi::mf0<unsigned long, boost::asio::io_service>&,
boost::_bi::list0&, long) (in /tmp/a.out)
==7737==    by 0x42FD66: boost::_bi::bind_t<unsigned long,
boost::_mfi::mf0<unsigned long, boost::asio::io_service>,
boost::_bi::list1<boost::_bi::value<boost::shared_ptr<boost::asio::io_service>
> > >::operator()() (in /tmp/a.out)
==7737==    by 0x42EE79:
boost::detail::thread_data<boost::_bi::bind_t<unsigned long,
boost::_mfi::mf0<unsigned long, boost::asio::io_service>,
boost::_bi::list1<boost::_bi::value<boost::shared_ptr<boost::asio::io_service>
> > > >::run() (in /tmp/a.out)
==7737==    by 0x4E41F5F: thread_proxy (in
/usr/local/lib/libboost_thread.so.1.43.0)
==7737==    by 0x4C2EA60: vgDrd_thread_wrapper (drd_pthread_intercepts.c:272)
==7737== mutex 0x61820f8 was first observed at:
==7737==    at 0x4C2EC6B: pthread_mutex_init (drd_pthread_intercepts.c:537)
==7737==    by 0x40AB63:
boost::asio::detail::posix_mutex::posix_mutex() (in /tmp/a.out)
==7737==    by 0x410B72:
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>::task_io_service(boost::asio::io_service&)
(in /tmp/a.out)
==7737==    by 0x40F679: boost::asio::io_service::service*
boost::asio::detail::service_registry::create<boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>
>(boost::asio::io_service&) (in /tmp/a.out)
==7737==    by 0x40ADB8:
boost::asio::detail::service_registry::do_use_service(boost::asio::io_service::service::key
const&, boost::asio::io_service::service*
(*)(boost::asio::io_service&)) (in /tmp/a.out)
==7737==    by 0x40DDDE:
boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>&
boost::asio::detail::service_registry::use_service<boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor>
>() (in /tmp/a.out)
==7737==    by 0x417C48: boost::asio::io_service::io_service() (in /tmp/a.out)
==7737==    by 0x416921:
http::server2::io_service_pool::io_service_pool(unsigned long) (in
/tmp/a.out)
==7737==    by 0x437816: http::server2::server::server(std::string
const&, std::string const&, std::string const&, unsigned long) (in
/tmp/a.out)
==7737==    by 0x43064D: main (in /tmp/a.out)
==7737==
^C==7737==
==7737== For counts of detected and suppressed errors, rerun with: -v
==7737== ERROR SUMMARY: 3 errors from 2 contexts (suppressed: 225 from 194)