sorry for the cryptic question title. I'm having a strange problem and i have no idea why it is happening. Fortunately, the code involved is pretty simple. But beofre we get to it, let me briefly describe my app. It is a multithreaded app that serves a large amount of data. Something like an in-ram database. It is possible to have multiple "databases" in it and load/unload them at runtime. Now the problem is with the memory deallocation. Please see the code bellow (names of classes etc are changed, but this should not matter):
void SS::AllocTree( double*** pba, int i, int d, int b, int split )
{
this->m_tree = new my_tree( pba, i, d, b, split );
}
void SS::DeallocTree()
{
delete this->m_tree;
this->m_tree = NULL;
}
Every time delete this->m_tree is called, the program crashes. The stack trace looks like this:
mydll.dll!_free_base(void * pBlock=0x0000000008496f70) Line 109 + 0x14 bytes C
mydll.dll!_free_dbg_nolock(void * pUserData=0x0000000008496fa0, int nBlockUse=0x00000001) Line 1428 C++
mydll.dll!_free_dbg(void * pUserData=0x0000000008496fa0, int nBlockUse=0x00000001) Line 1258 + 0xe bytes C++
mydll.dll!operator delete(void * pUserData=0x0000000008496fa0) Line 54 + 0x12 bytes C++
mydll.dll!my_tree::`vector deleting destructor'() + 0x94 bytes C++
myprog.exe!SS::DeallocTree() Line 57 + 0x34 bytes C++
myprog.exe!SSUnloader(void * arg=0x00000000084d6f80) Line 1038 C++
msvcr90d.dll!_callthreadstart() Line 295 C
msvcr90d.dll!_threadstart(void * ptd=0x00000000084dad30) Line 277 C
Here is the stack trace for the allocation of the tree:
msvcr90d.dll!malloc(unsigned __int64 nSize=0x0000000000000058) Line 56 + 0x21 bytes C++
msvcr90d.dll!operator new(unsigned __int64 size=0x0000000000000058) Line 59 + 0xa bytes C++
myprog.exe!SS::AllocTree(double * * * pba=0x0000000008458ff0, int i=0x00000bde, int d=0x00000010, int b=0x00000008, int split=0x00000001) Line 52 + 0xa bytes C++
myprog.exe!SSLoader(void * arg=0x000000000843cf80) Line 932 C++
msvcr90d.dll!_callthreadstart() Line 295 C
msvcr90d.dll!_threadstart(void * ptd=0x0000000008440d30) Line 277 C
As you can see the loading/unloading is done by a separate thread specifically created for this task. Nothe that i do not use any fancy things, no custom heaps or anything, no custom operator new/delete in my dll or my program. I have no idea why does the program go into my dll and call delete there but with new, this does not happen. If I change the DeallocTree() to look like this:
void SS::DeallocTree()
{
::operator delete( this->m_tree );
this->m_tree = NULL;
}
Then everything works fine. However, i am not sure if this is correct. Shouldnt i do something similar for operator new? And how can i be sure this same problem does not occur anywhere else? For completness sake i am also attaching the stack trace for this version of DeallocTree():
msvcr90d.dll!operator delete(void * pUserData=0x00000000086f5fa0) Line 45 + 0xa bytes C++
myprog.exe!SS::DeallocTree() Line 58 C++
myprog.exe!SSUnloader(void * arg=0x0000000008735f80) Line 1038 C++
msvcr90d.dll!_callthreadstart() Line 295 C
msvcr90d.dll!_threadstart(void * ptd=0x0000000008739d30) Line 277 C
Can someone explain to me what is going on here?
EDIT:
To clarify:
my.dll is loaded dynamically - VS 2008 output:
myprog.exe': Loaded 'C:*\Debug\mydll.dll', Symbols loaded.
Note: i am correctly using debug version of the dll with debug version of my program and vice versa with release.
**my_tree is declared as: my_tree* m_tree; // the tree
