Does boost::interprocess::windows_shared_memory require any special initialization when used from inside a DLL?

Question

I asked a boost-interprocess question before, and swore I'd stop using it, but alas, I am stuck and I really need this thing to work. So I'm still fighting with it.

I am having a strange crash when allocating and then immediately destroying a boost::interprocess::managed_windows_shared_memory::segment_manager but it only happens from within a Windows DLL project that I am building. I tried to reproduce it in a standalone program as a way to report it to Boost, but it does not reproduce outside my own DLL.

It also happens when I create the object normally and free it at a more sane time, but what I am trying to show here is that Boost is able to create an object, and that no time has gone by and no state has changed in the heap, and yet Boost is not able to free this object without crashing.

This does not happen in a standalone sample project (I built one, just to see if it would), but yet, NO other code that I am aware of is running in the project where it is crashing.

What is really weird is that it is crashing from the DLLMain function, and it is the very first thing in the DLLMain function is allocating and then destroying this C++ boost object. Something is strange about this boost object that it creates a whole lot of stuff (a redblack-tree) and then cannot even clean itself up.

The code below is almost but not quite enough to reproduce the issue. There is something wrong with my DLL, that renders the resulting Boost objects able to create themselves, but they crash at shutdown:

// BoostDllMain.cpp :
//
//  Attempt to demonstrate an insane situation in my code, where
//  boost::interprocess::managed_windows_shared_memory::segment_manager 
//  can be created, but freeing it causes access violations. The context
//  for object creation and destruction is DLL load and unload time.



#include "stdafx.h"

#include <objbase.h>
#include <windows.h>



#ifdef PERSISTENT_SHARED_MEM
#include <boost/interprocess/managed_shared_memory.hpp>
#else
#include <boost/interprocess/managed_windows_shared_memory.hpp>
#endif

#include <boost/interprocess/containers/map.hpp>
#include <boost/interprocess/allocators/allocator.hpp>
#include <boost/interprocess/containers/string.hpp>
#include <functional>
#include <utility>

#define SHARED_AREA_SIZE (1024*1024*8)  // 8 megabytes of shared memory should be enough to store more than 60K data points. 
                                    // In testing using current structure sizes, allocation Failed at the 61678th 
                                    // data point item when set to this value.



#ifdef PERSISTENT_SHARED_MEM
typedef boost::interprocess::managed_shared_memory                  mgr;
typedef boost::interprocess::managed_shared_memory::segment_manager seg;
#else
typedef boost::interprocess::managed_windows_shared_memory                  mgr;
typedef boost::interprocess::managed_windows_shared_memory::segment_manager seg;
#endif

using namespace boost::interprocess;

mgr *       segment1;
mgr *       segment2;

void Init(void) {

// Tweak C Runtime Debug Heap Flags.
int tmpFlag = _CrtSetDbgFlag( _CRTDBG_REPORT_FLAG );
tmpFlag |= _CRTDBG_LEAK_CHECK_DF;
tmpFlag |= _CRTDBG_CHECK_CRT_DF;
_CrtSetDbgFlag( tmpFlag );  

      segment1 = new mgr(   open_or_create
                           , "ED3_MEMORY" // This is a global memory area name

                           , SHARED_AREA_SIZE );    
      segment2 = new mgr(   open_or_create
                           , "ED3_MEMORY" // This is a global memory area name

                           , SHARED_AREA_SIZE );  
}

void Cleanup(void) {

     delete segment1;
     segment1 = NULL;


     delete segment2;
     segment2 = NULL;


}

//
extern "C"
BOOL WINAPI DllMain(IN HANDLE hInstance, IN DWORD dwReason, IN VOID *pReserved )
{



    switch ( dwReason )
    {
    case DLL_PROCESS_ATTACH:

        Init();

        break;

    case DLL_THREAD_ATTACH:
    case DLL_THREAD_DETACH:
        break;

    case DLL_PROCESS_DETACH:

        Cleanup();


        break;

    default:
        break;
    }

    return(1);
}

In short, with managed_windows_shared_memory, whatever object you create, is not even destroyable cleanly (without access violations) even right away, which is what I am trying to show above, where I create the object when the DLL loads, and destroy it when the DLL unloads.

Here's a stack traceback. if you can make any sense of it, you're probably a C++ compiler, rather than a human being, but here it is anyways:

>   mydll.dll!boost::interprocess::offset_ptr<boost::intrusive::compact_rbtree_node<boost::interprocess::offset_ptr<void,int,unsigned int,0> >,int,unsigned int,0>::offset_ptr<boost::intrusive::compact_rbtree_node<boost::interprocess::offset_ptr<void,int,unsigned int,0> >,int,unsigned int,0>(const boost::interprocess::offset_ptr<boost::intrusive::compact_rbtree_node<boost::interprocess::offset_ptr<void,int,unsigned int,0> >,int,unsigned int,0> & ptr={...})  Line 272 + 0xf bytes   C++
    mydll.dll!boost::intrusive::compact_rbtree_node_traits_impl<boost::interprocess::offset_ptr<void,int,unsigned int,0> >::get_left(const boost::interprocess::offset_ptr<boost::intrusive::compact_rbtree_node<boost::interprocess::offset_ptr<void,int,unsigned int,0> >,int,unsigned int,0> & n={...})  Line 142 + 0x1d bytes   C++
    mydll.dll!boost::intrusive::detail::tree_algorithms<boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1> >::dispose_subtree<boost::intrusive::detail::node_disposer<boost::intrusive::detail::null_disposer,boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int>,boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,1,boost::intrusive::default_tag,3>,std::less<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int> >,unsigned int,1> > > >(boost::interprocess::offset_ptr<boost::intrusive::compact_rbtree_node<boost::interprocess::offset_ptr<void,int,unsigned int,0> >,int,unsigned int,0> x={...}, boost::intrusive::detail::node_disposer<boost::intrusive::detail::null_disposer,boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int>,boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,1,boost::intrusive::default_tag,3>,std::less<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int> >,unsigned int,1> > > disposer={...})  Line 1298 + 0xd bytes  C++
    mydll.dll!boost::intrusive::detail::tree_algorithms<boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1> >::clear_and_dispose<boost::intrusive::detail::node_disposer<boost::intrusive::detail::null_disposer,boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int>,boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,1,boost::intrusive::default_tag,3>,std::less<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int> >,unsigned int,1> > > >(const boost::interprocess::offset_ptr<boost::intrusive::compact_rbtree_node<boost::interprocess::offset_ptr<void,int,unsigned int,0> >,int,unsigned int,0> & header={...}, boost::intrusive::detail::node_disposer<boost::intrusive::detail::null_disposer,boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int>,boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,1,boost::intrusive::default_tag,3>,std::less<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int> >,unsigned int,1> > > disposer={...})  Line 577 + 0x15 bytes   C++
    mydll.dll!boost::intrusive::rbtree_algorithms<boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1> >::clear_and_dispose<boost::intrusive::detail::node_disposer<boost::intrusive::detail::null_disposer,boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int>,boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,1,boost::intrusive::default_tag,3>,std::less<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int> >,unsigned int,1> > > >(const boost::interprocess::offset_ptr<boost::intrusive::compact_rbtree_node<boost::interprocess::offset_ptr<void,int,unsigned int,0> >,int,unsigned int,0> & header={...}, boost::intrusive::detail::node_disposer<boost::intrusive::detail::null_disposer,boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int>,boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,1,boost::intrusive::default_tag,3>,std::less<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int> >,unsigned int,1> > > disposer={...})  Line 451 + 0x16 bytes C++
    mydll.dll!boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int>,boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,1,boost::intrusive::default_tag,3>,std::less<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int> >,unsigned int,1> >::clear_and_dispose<boost::intrusive::detail::null_disposer>(boost::intrusive::detail::null_disposer disposer={...})  Line 1006 + 0x26 bytes C++
    mydll.dll!boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int>,boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,1,boost::intrusive::default_tag,3>,std::less<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int> >,unsigned int,1> >::clear()  Line 987  C++
    mydll.dll!boost::intrusive::detail::clear_on_destructor_base<boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int>,boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,1,boost::intrusive::default_tag,3>,std::less<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int> >,unsigned int,1> > >::~clear_on_destructor_base<boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int>,boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,1,boost::intrusive::default_tag,3>,std::less<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int> >,unsigned int,1> > >()  Line 27  C++
    mydll.dll!boost::intrusive::rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int>,boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,1,boost::intrusive::default_tag,3>,std::less<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int> >,unsigned int,1> >::~rbtree_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int>,boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,1,boost::intrusive::default_tag,3>,std::less<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int> >,unsigned int,1> >()  Line 284 + 0x14 bytes  C++
    mydll.dll!boost::intrusive::set_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int>,boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,1,boost::intrusive::default_tag,3>,std::less<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int> >,unsigned int,1> >::~set_impl<boost::intrusive::setopt<boost::intrusive::detail::base_hook_traits<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int>,boost::intrusive::rbtree_node_traits<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,1,boost::intrusive::default_tag,3>,std::less<boost::interprocess::ipcdetail::intrusive_value_type_impl<boost::intrusive::detail::generic_hook<boost::intrusive::get_set_node_algo<boost::interprocess::offset_ptr<void,int,unsigned int,0>,1>,boost::intrusive::default_tag,1,3>,char,unsigned int> >,unsigned int,1> >()  Line 139 + 0x14 bytes    C++
    mydll.dll!boost::interprocess::iset_index<boost::interprocess::ipcdetail::index_config<char,boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,boost::interprocess::offset_ptr<void,int,unsigned int,0>,0> > >::~iset_index<boost::interprocess::ipcdetail::index_config<char,boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,boost::interprocess::offset_ptr<void,int,unsigned int,0>,0> > >()  + 0x14 bytes    C++
    mydll.dll!boost::interprocess::segment_manager<char,boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,boost::interprocess::offset_ptr<void,int,unsigned int,0>,0>,boost::interprocess::iset_index>::header_t::~header_t()  + 0x3d bytes    C++
    mydll.dll!boost::interprocess::segment_manager<char,boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,boost::interprocess::offset_ptr<void,int,unsigned int,0>,0>,boost::interprocess::iset_index>::~segment_manager<char,boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,boost::interprocess::offset_ptr<void,int,unsigned int,0>,0>,boost::interprocess::iset_index>()  + 0x3d bytes  C++
    mydll.dll!boost::interprocess::segment_manager<char,boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,boost::interprocess::offset_ptr<void,int,unsigned int,0>,0>,boost::interprocess::iset_index>::`scalar deleting destructor'()  + 0x14 bytes   C++

In short I have

A. ruled out heap corruption from code written by me, because no other code has run in this DLL's context yet. Other objects can be created and freed, no problem, only this Boost object is unable to be created or destroyed in this DLL.

B. The DLL project is being compiled with the code generation set as "Multithreaded Debug DLL".

C. The destructor for boost::interprocess::managed_windows_shared_memory::segment_manager always crashes in the same place, it's not random in any way. That place is mydll.dll!boost::interprocess::offset_ptr<boost::intrusive::compact_rbtree_node<....

D. If I switch from the Windows shared memory, in this DLL context, to the other option, merely called shared_memory, it freezes up/deadlocks in get_last_bootup_time on a WMI call. This is a function from win32_api.hpp, that does a Window WMI function call and is trying to read class Win32_OperatingSystem property LastBootUpTime.

E. I'm starting to think that DLLs and Boost don't like each other, for weird weird reasons, perhaps involving CoInitialize, and dark black magic.

How do you debug something this crazy?

Answer 1

DllMain has some pretty harsh limitations based on the fact that you are holding the Loader Lock upon entry to this function, and the library loader won't calculate library dependencies properly if you load libraries in DllMain.

The really tricky part about all of this is that you can't hold the Loader Lock directly or indirectly. For example: you can't call LoadLibrary, synchronize with other threads, call CreateThread, call memory management functions from CRT, or call anything from User32. Please read the DLL best practices guide here (Microsoft), and look at the references at the end of the document.

Short answer: don't load this stuff in DllMain.