I recently get a memory dump of a hanging process. So I opened it with windbg 6.10.3.233
  The main thread was looking like this:
  0:00> ~0 kb  
ChildEBP RetAddr  Args to Child           
0012c72c 7c90e9c0 7c91901b 0000056c 00000000 ntdll!KiFastSystemCallRet   
0012c730 7c91901b 0000056c 00000000 00000000 ntdll!ZwWaitForSingleObject+0xc   
0012c7b8 7c90104b 0097e4c0 7c910945 7c97e4c0 ntdll!RtlpWaitForCriticalSection+0x132   
0012c7c0 7c910945 7c97e4c0 ffffffff 00000000 ntdll!RtlEnterCriticalSection+0x46   
0012c800 7c80e2cf ffffffff 7c80e038 00000000 ntdll!RtlAcquirePebLock+0x28   
0012c868 7c80e00d 7c80e038 00020690 00000000 kernel32!BasepComputeProcessPath+0x5f   
0012c8a8 7c801b83 00000000 00000000 0012d7a0 kernel32!BaseComputeProcessDllPath+0xe3   
0012c908 7c801d6e 7ffdfc00 00000000 00000000 kernel32!LoadLibraryExW+0x12f   
0012c91c 7c801da4 06057954 00000000 00000000 kernel32!LoadLibraryExA+0x1f   
0012c938 060b4823 06057954 7c911993 03f41ea8 kernel32!LoadLibraryA+0x94
  Sieextpub's very usefull !critlist extension showed me were whose holding the critical section:
  0:000> !critlist  
CritSec at 7c97e4c0.  Owned by thread 6.
Waiting Threads: 0 21    
CritSec at 7c97c0d8.  Owned by thread 21.
Waiting Threads: 22 
  SOS!Threads told me that it's a managed thread from the thread pool:
  0:006> !Threads  
ThreadCount: 5   
UnstartedThread: 0   
BackgroundThread: 5   
PendingThread: 0   
DeadThread: 0   
Hosted Runtime: no   
                                    PreEmptive   GC Alloc           Lock   
     ID OSID ThreadOBJ    State     GC       Context       Domain   Count APT Exception   
 0    1  ea4 001886e0      4220 Enabled  00000000:00000000 0019c7b8     1 STA System.Runtime.InteropServices.SEHException (0177d128)   
 2    2  2c0 001a6210      b220 Enabled  00000000:00000000 0019c7b8     0 MTA (Finalizer)   
 3    3  d7c 001efbd0    80a220 Enabled  00000000:00000000 0019c7b8     0 MTA (Threadpool Completion Port)   
 4    4  894 00223760   880b220 Enabled  00000000:00000000 0019c7b8     0 MTA (Threadpool Completion Port)   
 6    5  650 00224310   180b220 Enabled  017d2770:017d4608 0019c7b8     0 MTA (Threadpool Worker)
  Now I wanted to get the Stack Dump for thread number 6: 
  0:006> !CLRStack  
OS Thread Id: 0x650 (6)   
ESP       EIP  
0522f3bc 7c913da4 [NDirectMethodFrameStandalone: 0522f3bc]    
0522f3d4 79364aef    
0522f8f8 793644ae    
0522f900 793821b0    
0522f90c 793820f6    
0522f928 79381dbe    
0522f950 79381d16    
0522f968 793a2014    
0522f980 04189669    
0522f9a0 041892b2    
0522fa08 0418916f    
0522fa38 79407caa    
0522fa3c 79373ecd    
0522fa54 79407e18    
0522fa68 79407d90    
0522fbf8 79e7c74b [GCFrame: 0522fbf8] 
    Oops? OK - sometimes !DumpStack does a better job:
  0:006> !DumpStack  
OS Thread Id: 0x650 (6)   
Current frame: ntdll!RtlGetFullPathName_Ustr+0x653   
ChildEBP RetAddr  Caller,Callee   
0522f2d0 79e75002 mscorwks!FrameWithCookie<HelperMethodFrame>::FrameWithCookie<HelperMethodFrame>+0x1e, calling mscorwks!HelperMethodFrame::HelperMethodFrame   
0522f318 7c91056d ntdll!RtlFreeHeap+0x647, calling ntdll!_SEH_epilog   
0522f33c 7c9141e4 ntdll!RtlGetFullPathName_U+0x33, calling ntdll!RtlGetFullPathName_Ustr   
0522f364 7c80b86c kernel32!GetFullPathNameW+0x1a, calling ntdll!RtlGetFullPathName_U   
0522f37c 015da1c3 015da1c3   
0522f3a4 79364aef 79364aef, calling 796c00cc   
0522f3c4 79364aef 79364aef, calling 796c00cc   
0522f8f0 793644ae 793644ae, calling 793644b8   
0522f8f8 793821b0 793821b0, calling 79364480   
0522f904 793820f6 793820f6, calling 79382120   
0522f920 79381dbe 79381dbe, calling 79381fac   
0522f934 79381d16 79381d16, calling 79381d54   
0522f95c 793a2014 793a2014, calling 79381cd4   
0522f978 04189669 04189669   
0522f994 041892b2 041892b2, calling 04189600   
0522fa00 0418916f 0418916f, calling 04189208   
0522fa30 79407caa 79407caa   
0522fa34 79373ecd 79373ecd   
0522fa48 79407e18 79407e18, calling 79373e4c   
0522fa60 79407d90 79407d90, calling 79407dc8   
0522fa74 79e7c74b mscorwks!CallDescrWorker+0x33   
0522fa84 79e7c6cc mscorwks!CallDescrWorkerWithHandler+0xa3, calling mscorwks!CallDescrWorker   
0522fb04 79f00eca mscorwks!DispatchCallBody+0x1e, calling mscorwks!CallDescrWorkerWithHandler   
0522fb24 79f00e75 mscorwks!DispatchCallDebuggerWrapper+0x3d, calling mscorwks!DispatchCallBody   
0522fb88 79f00f03 mscorwks!DispatchCallNoEH+0x51, calling mscorwks!DispatchCallDebuggerWrapper   
0522fbbc 79f6e39d mscorwks!QueueUserWorkItemManagedCallback+0x6c, calling mscorwks!DispatchCallNoEH   
0522fc1c 79ef3207 mscorwks!Thread::DoADCallBack+0x32a   
0522fc30 79ef31a3 mscorwks!Thread::ShouldChangeAbortToUnload+0xe3, calling mscorwks!Thread::DoADCallBack+0x2db   
0522fc58 79e744d0 mscorwks!Thread::EnterRuntimeNoThrow+0x94, calling ntdll!RtlSetLastWin32Error   
0522fc5c 79e744d7 mscorwks!Thread::EnterRuntimeNoThrow+0x9b, calling mscorwks!_EH_epilog3   
0522fcc4 79ef30c3 mscorwks!Thread::ShouldChangeAbortToUnload+0x30a, calling mscorwks!Thread::ShouldChangeAbortToUnload+0x32   
0522fd00 79ef4826 mscorwks!Thread::ShouldChangeAbortToUnload+0x33e, calling mscorwks!Thread::ShouldChangeAbortToUnload+0x29d   
0522fd28 79ef48cf mscorwks!ManagedThreadBase::ThreadPool+0x13, calling mscorwks!Thread::ShouldChangeAbortToUnload+0x319   
0522fd40 79f6e2d8 mscorwks!ManagedPerAppDomainTPCount::DispatchWorkItem+0xdb, calling mscorwks!ManagedThreadBase::ThreadPool   
0522fd94 79f022c7 mscorwks!PerAppDomainTPCountList::GetAppDomainIndexForThreadpoolDispatch+0x35   
0522fda8 79f0202a mscorwks!ThreadpoolMgr::ExecuteWorkRequest+0xaf   
0522fdbc 79f021a0 mscorwks!ThreadpoolMgr::WorkerThreadStart+0x223, calling mscorwks!ThreadpoolMgr::ExecuteWorkRequest   
0522fe14 79f95a2e mscorwks!Thread::intermediateThreadProc+0x49   
0522ffa0 79f95a1c mscorwks!Thread::intermediateThreadProc+0x37, calling mscorwks!_alloca_probe_16   
0522ffb4 7c80b683 kernel32!BaseThreadStart+0x37
   
  Not really better, eh?
  So I launched my good old 6.7.5.0 (which lives side by side with the latest windbg on my machine - thanks to xcopy) and surprise:
  [click image to enlarge]
   
 
  The call stack window did a wonderful job and I even got pointed to the corresponding source code.
  As it is the same sos, a !DumpStack did not do the job in 6.7.5.0 either.
   
  So please Microsoft, give us back the this very very helpful feature of 6.7.5.0!
Or at least make SOS working like the stack window of 6.7.5.0.