11
Khi tôi chuyển mã của tôi sang C++ 11, tôi rất muốn chuyển mã pthread thành std :: thread. Tuy nhiên, tôi dường như nhận được điều kiện cuộc đua sai trên các chương trình rất đơn giản trong drd và trong helgrind.Trạng thái hiện tại của drd và helgrind hỗ trợ cho std :: thread
#include <thread>
int main(int argc, char** argv)
{
std::thread t([]() { });
t.join();
return 0;
}
Đoạn trích đầu ra Helgrind - Tôi cũng gặp lỗi tương tự trong drd, sử dụng gcc 4.6.1, valgrind 3.7.0 trên Ubuntu 11.11 amd64.
Câu hỏi của tôi là: kiểm tra
- sự tỉnh táo: Tôi có làm điều gì sai trái? Những người khác nhận được báo cáo sai tương tự về chương trình std :: thread đơn giản?
- Người dùng hiện tại của std :: thread sử dụng để phát hiện điều kiện chủng tộc là gì?
Tôi không muốn chuyển một tấn mã từ pthread sang std::thread cho đến khi một số công cụ quan trọng như helgrind/drd đã bắt kịp.
==19347== ---Thread-Announcement------------------------------------------
==19347==
==19347== Thread #1 is the program's 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==
+1 mẹo tuyệt vời! Tôi chắc chắn sẽ thử nó - thx. – kfmfe04
Lưu ý: chỉ phát hiện ra rằng có lỗi trong libstdC++ không cho phép std :: thread được chú thích đúng cách - xem thêm [gcc bug 51504] (http://gcc.gnu.org/bugzilla/show_bug.cgi ? id = 51504). – user251384