При переходе моего кода на С++ 11, я бы очень хотел преобразовать свой код pthread в std:: thread. Тем не менее, я, кажется, получаю ложные условия гонки на очень простых программах в drd и helgrind.
#include <thread>
int main(int argc, char** argv)
{
std::thread t( []() { } );
t.join();
return 0;
}
Отказоустойчивый вывод helgrind. Я также получаю подобные ошибки в drd, используя gcc 4.6.1, valgrind 3.7.0 на Ubuntu 11.11 amd64.
Мои вопросы:
- Проверка здравомыслия: я делаю что-то неправильно? Другие получают похожие ложные отчеты о простых программах std:: thread?
- Какие текущие пользователи используют std:: thread для определения условий гонки?
Я не хочу переносить тонну кода с pthread на std::thread
до тех пор, пока не появятся некоторые важные инструменты, такие как helgrind/drd.
==19347== ---Thread-Announcement------------------------------------------
==19347==
==19347== Thread #1 is the program root thread
==19347==
==19347== ---Thread-Announcement------------------------------------------
==19347==
==19347== Thread #2 was created
==19347== at 0x564C85E: clone (clone.S:77)
==19347== by 0x4E37E7F: do_clone.constprop.3 (createthread.c:75)
==19347== by 0x4E39604: [email protected]@GLIBC_2.2.5 (createthread.c:256)
==19347== by 0x4C2B3DA: pthread_create_WRK (hg_intercepts.c:255)
==19347== by 0x4C2B55E: [email protected]* (hg_intercepts.c:286)
==19347== by 0x50BED02: std::thread::_M_start_thread(std::shared_ptr<std::thread::_Impl_base>) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.16)
==19347== by 0x400D51: _ZNSt6threadC1IZ4mainEUlvE_IEEEOT_DpOT0_ (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x400C60: main (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347==
==19347== ----------------------------------------------------------------
==19347==
==19347== Possible data race during write of size 8 at 0x5B8E060 by thread #1
==19347== Locks held: none
==19347== at 0x40165E: _ZNSt6thread5_ImplISt12_Bind_resultIvFZ4mainEUlvE_vEEED1Ev (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x401895: _ZNKSt19_Sp_destroy_inplaceINSt6thread5_ImplISt12_Bind_resultIvFZ4mainEUlvE_vEEEEEclEPS6_ (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x4016D8: _ZNSt19_Sp_counted_deleterIPNSt6thread5_ImplISt12_Bind_resultIvFZ4mainEUlvE_vEEEESt19_Sp_destroy_inplaceIS6_ESaIS6_ELN9__gnu_cxx12_Lock_policyE2EE10_M_disposeEv (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x401B83: std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release() (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x401B3E: std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count() (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x401A93: std::__shared_ptr<std::thread::_Impl_base, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr() (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x401AAD: std::shared_ptr<std::thread::_Impl_base>::~shared_ptr() (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x400D5D: _ZNSt6threadC1IZ4mainEUlvE_IEEEOT_DpOT0_ (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x400C60: main (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347==
==19347== This conflicts with a previous read of size 8 by thread #2
==19347== Locks held: none
==19347== at 0x50BEABE: ??? (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.16)
==19347== by 0x4C2B547: mythread_wrapper (hg_intercepts.c:219)
==19347== by 0x4E38EFB: start_thread (pthread_create.c:304)
==19347== by 0x564C89C: clone (clone.S:112)
==19347==
==19347== Address 0x5B8E060 is 32 bytes inside a block of size 64 alloc'd
==19347== at 0x4C29059: operator new(unsigned long) (vg_replace_malloc.c:287)
==19347== by 0x4012E9: _ZN9__gnu_cxx13new_allocatorISt23_Sp_counted_ptr_inplaceINSt6thread5_ImplISt12_Bind_resultIvFZ4mainEUlvE_vEEEESaIS8_ELNS_12_Lock_policyE2EEE8allocateEmPKv (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x40117C: _ZNSt14__shared_countILN9__gnu_cxx12_Lock_policyE2EEC1INSt6thread5_ImplISt12_Bind_resultIvFZ4mainEUlvE_vEEEESaISA_EIS9_EEESt19_Sp_make_shared_tagPT_RKT0_DpOT1_ (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x4010B9: _ZNSt12__shared_ptrINSt6thread5_ImplISt12_Bind_resultIvFZ4mainEUlvE_vEEEELN9__gnu_cxx12_Lock_policyE2EEC1ISaIS6_EIS5_EEESt19_Sp_make_shared_tagRKT_DpOT0_ (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x401063: _ZNSt10shared_ptrINSt6thread5_ImplISt12_Bind_resultIvFZ4mainEUlvE_vEEEEEC1ISaIS6_EIS5_EEESt19_Sp_make_shared_tagRKT_DpOT0_ (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x401009: _ZSt15allocate_sharedINSt6thread5_ImplISt12_Bind_resultIvFZ4mainEUlvE_vEEEESaIS6_EIS5_EESt10shared_ptrIT_ERKT0_DpOT1_ (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x400EF7: _ZSt11make_sharedINSt6thread5_ImplISt12_Bind_resultIvFZ4mainEUlvE_vEEEEIS5_EESt10shared_ptrIT_EDpOT0_ (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x400E17: _ZNSt6thread15_M_make_routineISt12_Bind_resultIvFZ4mainEUlvE_vEEEESt10shared_ptrINS_5_ImplIT_EEEOS7_ (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x400D2B: _ZNSt6threadC1IZ4mainEUlvE_IEEEOT_DpOT0_ (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347== by 0x400C60: main (in /mnt/home/kfeng/dev/robolab/cpp/sbx/sandbox)
==19347==
==19347== ----------------------------------------------------------------
==19347==