It seems that the extremely useful
!locks command is broken in 188.8.131.52x, the current and previous release of WinDbg from the debugging tools for Windows.
You’ll get errors like:
0:007> !locks NTSDEXTS: Unable to resolve ntdll!RTL_CRITICAL_SECTION_DEBUG type NTSDEXTS: Please check your symbols
The suggested solution seems to be to roll-back to version 184.108.40.206, available from here, or you can just replace the version of
ntsdexts.dll in the
c:\program files\debugging tools for windows (x86)\winxp directory with the one from the earlier release.
Judging by the error message, I’m guessing that the new version may work if you happen to be using a debug (checked) build of the Windows kernel, but I don’t have one around to try it with.