[Boost-users] [thread] race condition detected with valgrind drd

Subject: [Boost-users] [thread] race condition detected with valgrind drd
From: Jorge Moraleda (moraleda_at_[hidden])
Date: 2010-05-25 20:51:07

Dear all,

I must be doing something wrong, but I can't figure out what. I would
appreciate some help. Thank you in advance.

The following program:

#include <boost/thread.hpp>

void threadEntry()
{
}

int main (int argc, char *argv[])
{
         for(size_t t=0; t<10; t++) {
                 boost::thread(threadEntry);
         }
}

runs cleanly with valgrind drd, but this other program produces race
conditions when run with valgrind drd (see below). The only difference
is "new".

#include <boost/thread.hpp>

void threadEntry()
{
}

int main (int argc, char *argv[])
{
         for(size_t t=0; t<10; t++) {
                 new boost::thread(threadEntry);
         }
}

This problem is not due to the leak, because this other program:

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

void threadEntry()
{
}

int main (int argc, char *argv[])
{
        
         std::vector<boost::shared_ptr<boost::thread> > threads;
         for(size_t t=0; t<10; t++) {
                boost::shared_ptr<boost::thread> thread(new boost::thread( threadEntry ));
                threads.push_back(thread);
         }
        
         for (size_t i = 0; i < threads.size(); ++i) {
                threads[i]->join();
         }
}

which properly manages the heap also produces the same race conditions.

I compile using:
g++ -g -L /opt/boost/boost/stage/lib -lboost_thread threads.cpp

and I test the program using valgrind using:
valgrind --tool=drd ./a.out

The output of valgrind is:
==3822== drd, a thread error detector
==3822== Copyright (C) 2006-2009, and GNU GPL'd, by Bart Van Assche.
==3822== Using Valgrind-3.5.0-Debian and LibVEX; rerun with -h for
copyright info
==3822== Command: ./a.out
==3822==
==3822== Thread 3:
==3822== Conflicting store by thread 3 at 0x0504b350 size 8
==3822==    at 0x4E417B3: ??? (in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E41B28:
boost::detail::set_current_thread_data(boost::detail::thread_data_base*)
(in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E42124: thread_proxy (in
/usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4C32870: vgDrd_thread_wrapper (drd_pthread_intercepts.c:272)
==3822==    by 0x5D74A03: start_thread (pthread_create.c:300)
==3822==    by 0x58D680C: clone (clone.S:112)
==3822== Allocation context: BSS section of
/usr/local/lib/libboost_thread.so.1.42.0
==3822== Other segment start (thread 2)
==3822==    at 0x58D67D1: clone (clone.S:84)
==3822==    by 0x5D7493F: ??? (allocatestack.c:743)
==3822==    by 0x6B8A90F: ???
==3822== Other segment end (thread 2)
==3822==    at 0x5D7A7C4: pthread_once (pthread_once.S:119)
==3822==    by 0x4C28ADD: pthread_once (drd_pthread_intercepts.c:518)
==3822==    by 0x4E473B3: boost::detail::get_once_per_thread_epoch()
(in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E4172F: ??? (in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E41B28:
boost::detail::set_current_thread_data(boost::detail::thread_data_base*)
(in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E42124: thread_proxy (in
/usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4C32870: vgDrd_thread_wrapper (drd_pthread_intercepts.c:272)
==3822==    by 0x5D74A03: start_thread (pthread_create.c:300)
==3822==    by 0x58D680C: clone (clone.S:112)
==3822==
==3822== Conflicting store by thread 3 at 0x0504b350 size 8
==3822==    at 0x4E417F9: ??? (in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E41B28:
boost::detail::set_current_thread_data(boost::detail::thread_data_base*)
(in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E42124: thread_proxy (in
/usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4C32870: vgDrd_thread_wrapper (drd_pthread_intercepts.c:272)
==3822==    by 0x5D74A03: start_thread (pthread_create.c:300)
==3822==    by 0x58D680C: clone (clone.S:112)
==3822== Allocation context: BSS section of
/usr/local/lib/libboost_thread.so.1.42.0
==3822== Other segment start (thread 2)
==3822==    at 0x58D67D1: clone (clone.S:84)
==3822==    by 0x5D7493F: ??? (allocatestack.c:743)
==3822==    by 0x6B8A90F: ???
==3822== Other segment end (thread 2)
==3822==    at 0x5D7A7C4: pthread_once (pthread_once.S:119)
==3822==    by 0x4C28ADD: pthread_once (drd_pthread_intercepts.c:518)
==3822==    by 0x4E473B3: boost::detail::get_once_per_thread_epoch()
(in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E4172F: ??? (in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E41B28:
boost::detail::set_current_thread_data(boost::detail::thread_data_base*)
(in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E42124: thread_proxy (in
/usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4C32870: vgDrd_thread_wrapper (drd_pthread_intercepts.c:272)
==3822==    by 0x5D74A03: start_thread (pthread_create.c:300)
==3822==    by 0x58D680C: clone (clone.S:112)
==3822== Other segment start (thread 2)
==3822==    at 0x58D67D1: clone (clone.S:84)
==3822==    by 0x5D7493F: ??? (allocatestack.c:743)
==3822==    by 0x6B8A90F: ???
==3822== Other segment end (thread 2)
==3822==    at 0x5D7A7C4: pthread_once (pthread_once.S:119)
==3822==    by 0x4C28ADD: pthread_once (drd_pthread_intercepts.c:518)
==3822==    by 0x4E473B3: boost::detail::get_once_per_thread_epoch()
(in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E4172F: ??? (in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E41B28:
boost::detail::set_current_thread_data(boost::detail::thread_data_base*)
(in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E42124: thread_proxy (in
/usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4C32870: vgDrd_thread_wrapper (drd_pthread_intercepts.c:272)
==3822==    by 0x5D74A03: start_thread (pthread_create.c:300)
==3822==    by 0x58D680C: clone (clone.S:112)
==3822==
==3822== Conflicting load by thread 3 at 0x05f85288 size 8
==3822==    at 0x5D73AEE: __nptl_deallocate_tsd (pthread_create.c:153)
==3822==    by 0x5D74A11: start_thread (pthread_create.c:307)
==3822==    by 0x58D680C: clone (clone.S:112)
==3822== Allocation context: BSS section of /lib/libpthread-2.10.1.so
==3822== Other segment start (thread 2)
==3822==    at 0x58D67D1: clone (clone.S:84)
==3822==    by 0x5D7493F: ??? (allocatestack.c:743)
==3822==    by 0x6B8A90F: ???
==3822== Other segment end (thread 2)
==3822==    at 0x5D7A7C4: pthread_once (pthread_once.S:119)
==3822==    by 0x4C28ADD: pthread_once (drd_pthread_intercepts.c:518)
==3822==    by 0x4E473B3: boost::detail::get_once_per_thread_epoch()
(in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E4172F: ??? (in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E41B28:
boost::detail::set_current_thread_data(boost::detail::thread_data_base*)
(in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E42124: thread_proxy (in
/usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4C32870: vgDrd_thread_wrapper (drd_pthread_intercepts.c:272)
==3822==    by 0x5D74A03: start_thread (pthread_create.c:300)
==3822==    by 0x58D680C: clone (clone.S:112)
==3822==
==3822== Thread 4:
==3822== Conflicting load by thread 4 at 0x0504b350 size 8
==3822==    at 0x4E41724: ??? (in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E41B28:
boost::detail::set_current_thread_data(boost::detail::thread_data_base*)
(in /usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4E42124: thread_proxy (in
/usr/local/lib/libboost_thread.so.1.42.0)
==3822==    by 0x4C32870: vgDrd_thread_wrapper (drd_pthread_intercepts.c:272)
==3822==    by 0x5D74A03: start_thread (pthread_create.c:300)
==3822==    by 0x58D680C: clone (clone.S:112)
==3822== Allocation context: BSS section of
/usr/local/lib/libboost_thread.so.1.42.0
==3822== Other segment start (thread 3)
==3822==    (thread finished, call stack no longer available)
==3822== Other segment end (thread 3)
==3822==    (thread finished, call stack no longer available)
==3822== Other segment start (thread 3)
==3822==    (thread finished, call stack no longer available)
==3822== Other segment end (thread 3)
==3822==    (thread finished, call stack no longer available)
==3822==
==3822==
==3822== For counts of detected and suppressed errors, rerun with: -v
==3822== ERROR SUMMARY: 11 errors from 4 contexts (suppressed: 126 from 76)