Crash in CAtlStringMgr::GetInstance under Windows XP

Question

I've written a DLL that creates an ATL CString object. I compile it with Visual Studio 2015 using the "Visual Studio 2015 - Windows XP (v140_xp)" platform toolset. The DLL is loaded using LoadLibrary/GetProcAddress.

It crashes under Windows XP in CAtlStringMrg::GetInstance when allocating the string object. The same application works well on Windows Vista and later.

Here is the disassembly:

    static IAtlStringMgr* GetInstance()
    {
#pragma warning(push)
#pragma warning(disable: 4640)
        static CWin32Heap strHeap( ::GetProcessHeap() );
1003B100 mov         eax,dword ptr fs:[0000002Ch] 
1003B106 mov         ecx,dword ptr [__tls_index (101B46C8h)] 
1003B10C push        esi 

*** This is the instruction that causes the crash. eax and ecx are zero. ***
1003B10D mov         esi,dword ptr [eax+ecx*4]

As you can see the code references __tls_index, thus it uses thread local storage. dumpbin also shows a .tls section that is not present when I compile my project with the old Visual Studio 2013.

Thread local storage is not supported on Windows XP when a DLL is loaded dynamically. This explains why the code above crashes.

However, I could not figure out why thread local storage is used. I can't find __declspec(thread) anywhere in the ATL sources.

I'm looking for a fix/workaround (other than going back from VS2015 to VS2013).

The issue has already been reported to Microsoft, but they did not comment/fix it yet: https://connect.microsoft.com/VisualStudio/feedback/details/1635157/crash-in-catlstringmrg-getinstance-under-windows-xp

Answer 1

Thanks to David to point me in the right direction. Here's the workaround:

Properties -> C/C++ -> Command Line -> add "/Zc:threadSafeInit-"

Related documents:

https://connect.microsoft.com/VisualStudio/feedback/details/1715018/dll-usage-of-thread-safe-magic-statics-may-crash-on-windows-xp

Access violation on static initialization

https://connect.microsoft.com/VisualStudio/feedback/details/1789709/visual-c-2015-runtime-broken-on-windows-server-2003-c-11-magic-statics

https://msdn.microsoft.com/en-us/library/vstudio/hh567368.aspx