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POWhy am I getting segfaults randomly?
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copied!<p>This is quite strange for me, but I'm getting an unexpected and random segmentation fault when I launch my program. Some times it works, some times it crashes.. The debugger of Dev-C++ points me to a line of the file : stl_construct.h</p> <pre><code>/** * @if maint * Constructs an object in existing memory by invoking an allocated * object's constructor with an initializer. * @endif */ template<typename _T1, typename _T2> inline void _Construct(_T1* __p, const _T2& __value) { // _GLIBCXX_RESOLVE_LIB_DEFECTS // 402. wrong new expression in [some_]allocator::construct -> ::new(static_cast<void*>(__p)) _T1(__value); } </code></pre> <p>I'm using the STL extensively by the way.. What should i do to detect the origin of the segfault? Are there any tools that can help? What are the reasons that can lead to random crashes like this.</p> <h3>Edit:</h3> <p>My program counts around 5000 lines of code. I don't know what piece of code I have to show in order to get some help since I have no clue about the origin of the problem, all I got from the debugger is that it has to do with the STL.</p> <h3>Edit:</h3> <p>I moved to <code>Code::Blocks</code> now, here is the call stack:</p> <pre><code>#0 00464635 std::_Construct<std::pair<double const, int>, std::pair<double const, int> >(__p=0xb543e8, __value=@0x10) (C:/Program Files/CodeBlocks/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../include/c++/3.4.5/bits/stl_construct.h:81) #1 00462306 std::_Rb_tree<double, std::pair<double const, int>, std::_Select1st<std::pair<double const, int> >, std::less<double>, std::allocator<std::pair<double const, int> > >::_M_create_node(this=0x406fe50, __x=@0x10) (C:/Program Files/CodeBlocks/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../include/c++/3.4.5/bits/stl_tree.h:367) #2 00461DA7 std::_Rb_tree<double, std::pair<double const, int>, std::_Select1st<std::pair<double const, int> >, std::less<double>, std::allocator<std::pair<double const, int> > >::_M_clone_node(this=0x406fe50, __x=0x0) (C:/Program Files/CodeBlocks/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../include/c++/3.4.5/bits/stl_tree.h:379) #3 004625C6 std::_Rb_tree<double, std::pair<double const, int>, std::_Select1st<std::pair<double const, int> >, std::less<double>, std::allocator<std::pair<double const, int> > >::_M_copy(this=0x406fe50, __x=0x0, __p=0x406fe54) (C:/Program Files/CodeBlocks/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../include/c++/3.4.5/bits/stl_tree.h:1029) #4 00462A9D std::_Rb_tree<double, std::pair<double const, int>, std::_Select1st<std::pair<double const, int> >, std::less<double>, std::allocator<std::pair<double const, int> > >::_Rb_tree(this=0x406fe50, __x=@0xb59a7c) (C:/Program Files/CodeBlocks/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../include/c++/3.4.5/bits/stl_tree.h:559) #5 0045A928 std::map<double, int, std::less<double>, std::allocator<std::pair<double const, int> > >::map(this=0x406fe50, __x=@0xb59a7c) (C:/Program Files/CodeBlocks/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../include/c++/3.4.5/bits/stl_map.h:166) #6 0040B7E2 VehicleManager::get_vehicles_distances(this=0xb59a50) (C:/Program Files/CodeBlocks/MinGW/projects/AHS/VehicleManager.cpp:232) #7 00407BDA Supervisor::IsMergeInstruction(id_vehicle=1) (C:/Program Files/CodeBlocks/MinGW/projects/AHS/Supervisor.cpp:77) #8 00408430 CheckingInstructionsThread(arg=0x476100) (C:/Program Files/CodeBlocks/MinGW/projects/AHS/Supervisor.cpp:264) #9 00413950 _glfwNewThread@4() (??:??) #10 75A24911 KERNEL32!AcquireSRWLockExclusive() (C:\Windows\system32\kernel32.dll:??) #11 00476100 std::__ioinit() (??:??) #12 0406FFD4 ??() (??:??) #13 76E5E4B6 ntdll!RtlInitializeNtUserPfn() (C:\Windows\system32\ntdll.dll:??) #14 00476100 std::__ioinit() (??:??) #15 70266582 ??() (??:??) #16 00000000 ??() (??:??) </code></pre> <p>A few more precisions :</p> <p>1/ It's a multi-threaded application. 2/ The method : get_vehicles_distances(); returns a map. 3/ It's possible that the map isn't initalised by the time when it's called by IsMergeInstruction(); </p> <h3>Edit:</h3> <p>Apparently the line that is causing the segfault is :</p> <pre><code>vehicles_distances_.erase(vehicles_distances_.begin(), vehicles_distances_.end()); </code></pre> <p>Where vehicles_distances_ is the Map. This line is a part of the method : VehicleManager::MoveAllVehicles();</p> <pre><code>void VehicleManager::MoveAllVehicles() { vehicles_distances_.erase(vehicles_distances_.begin(), vehicles_distances_.end()); vector<Vehicle>::iterator iter_end = VehicleManager::vehicles_.end(); for(vector<Vehicle>::iterator iter = VehicleManager::vehicles_.begin(); iter != iter_end; ++iter) { (*iter).MoveVehicle(); vehicles_distances_[(*iter).get_vec_vehicle_position().y] = (*iter).get_id_vehicle(); } } </code></pre> <p>What is wrong with that ?</p> <h3>Edit:</h3> <p>I tried to use map::clear(); as a replacement to map::erase(); but the same problem occurs!</p> <h3>Edit:</h3> <p>I think i get it... A thread is trying to make a use of vehicles_distances_ while it's cleared.. (?)</p> <h3>Edit:</h3> <p>Problem solved! So it was coming from the map::erase(); as expected. i bypassed the problem by creating another map variable where the pair <code><key, value></code> was inverted so i can update the map. (since the key that i need is the distance, and the distance isn't unique since it changes everytime but the id_vehicle is unique!). At the end i just took that map, inverted the <code><key, value></code> again and transferred it to the original map that can be redeclared in each cycle... </p> <p>Thanks everyone !</p>

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