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!cs

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The !cs extension displays one or more critical sections or the whole critical section tree.

!cs [-s] [-l] [-o] 
!cs [-s] [-o] Address 
!cs [-s] [-l] [-o] StartAddress EndAddress 
!cs [-s] [-o] -d InfoAddress 
!cs [-s] -t [TreeAddress] 
!cs -?

Parameters

Parameter Description
-s Displays each critical section's initialization stack trace, if this information is available.
-l Display only the locked critical sections.
-o Displays the owner's stack for any locked critical section that is being displayed.
Address Specifies the address of the critical section to display. If you omit this parameter, the debugger displays all critical sections in the current process.
StartAddress Specifies the beginning of the address range to search for critical sections.
EndAddress Specifies the end of the address range to search for critical sections.
-d Displays critical sections that are associated with DebugInfo.
InfoAddress Specifies the address of the DebugInfo.
-t Displays a critical section tree. Before you can use the -t option, you must activate Application Verifier for the target process and select the Check lock usage option.
TreeAddress Specifies the address of the root of the critical section tree. If you omit this parameter or specify zero, the debugger displays the critical section tree for the current process.
-? Displays some Help text for this extension in the Debugger Command window.

DLL

Exts.dll

Additional Information

For other commands and extensions that can display critical section information, see Displaying a Critical Section. For more information about critical sections, see the Microsoft Windows SDK documentation, the Windows Driver Kit (WDK) documentation, and Microsoft Windows Internals by Mark Russinovich and David Solomon.

Remarks

The !cs extension requires full symbols (including type information) for the process that is being debugged and for Ntdll.dll.

The following examples shows you how to use !cs. The following command displays information about the critical section at address 0x7803B0F8 and shows its initialization stack trace.

0:001> !cs -s 0x7803B0F8
Critical section   = 0x7803B0F8 (MSVCRT!__app_type+0x4)
DebugInfo          = 0x6A262080
NOT LOCKED
LockSemaphore      = 0x0
SpinCount          = 0x0

Stack trace for DebugInfo = 0x6A262080:

0x6A2137BD: ntdll!RtlInitializeCriticalSectionAndSpinCount+0x9B
0x6A207A4C: ntdll!LdrpCallInitRoutine+0x14
0x6A205569: ntdll!LdrpRunInitializeRoutines+0x1D9
0x6A20DCE1: ntdll!LdrpInitializeProcess+0xAE5

The following command displays information about the critical section whose DebugInfo is at address 0x6A262080.

0:001> !cs -d 0x6A262080
DebugInfo          = 0x6A262080
Critical section   = 0x7803B0F8 (MSVCRT!__app_type+0x4)
NOT LOCKED
LockSemaphore      = 0x0
SpinCount          = 0x0

The following command displays information about all of the active critical sections in the current process.

## 0:001> !cs

DebugInfo          = 0x6A261D60
Critical section   = 0x6A262820 (ntdll!RtlCriticalSectionLock+0x0)
LOCKED
LockCount          = 0x0
OwningThread       = 0x460
RecursionCount     = 0x1
LockSemaphore      = 0x0
## SpinCount          = 0x0

DebugInfo          = 0x6A261D80
Critical section   = 0x6A262580 (ntdll!DeferedCriticalSection+0x0)
NOT LOCKED
LockSemaphore      = 0x7FC
## SpinCount          = 0x0

DebugInfo          = 0x6A262600
Critical section   = 0x6A26074C (ntdll!LoaderLock+0x0)
NOT LOCKED
LockSemaphore      = 0x0
## SpinCount          = 0x0

DebugInfo          = 0x77fbde20
Critical section   = 0x77c8ba60 (GDI32!semColorSpaceCache+0x0)
LOCKED
LockCount          = 0x0
OwningThread       = 0x00000dd8
RecursionCount     = 0x1
LockSemaphore      = 0x0
## SpinCount          = 0x00000000

...

The following command displays the critical section tree.

0:001> !cs -t

Tree root 00bb08c0

Level     Node       CS    Debug  InitThr EnterThr  WaitThr TryEnThr LeaveThr EnterCnt  WaitCnt
## 


    0 00bb08c0 77c7e020 77fbcae0      4c8      4c8        0        0      4c8        c        0
 1 00dd6fd0 0148cfe8 01683fe0      4c8      4c8        0        0      4c8        2        0
 2 00bb0aa0 008e8b84 77fbcc20      4c8        0        0        0        0        0        0
    3 00bb09e0 008e8704 77fbcba0      4c8        0        0        0        0        0        0
    4 00bb0a40 008e8944 77fbcbe0      4c8        0        0        0        0        0        0
    5 00bb0a10 008e8824 77fbcbc0      4c8        0        0        0        0        0        0
    5 00bb0a70 008e8a64 77fbcc00      4c8        0        0        0        0        0        0
    3 00bb0b00 008e8dc4 77fbcc60      4c8        0        0        0        0        0        0
    4 00bb0ad0 008e8ca4 77fbcc40      4c8        0        0        0        0        0        0
    4 00bb0b30 008e8ee4 77fbcc80      4c8        0        0        0        0        0        0
    5 00dd4fd0 0148afe4 0167ffe0      4c8        0        0        0        0        0        0
    2 00bb0e90 77c2da98 00908fe0      4c8      4c8        0        0      4c8       3a        0
 3 00bb0d70 77c2da08 008fcfe0      4c8        0        0        0        0        0        0

The following items appear in this !cs -t display:

  • InitThr is the thread ID for the thread that initialized the CS.

  • EnterThr is the ID of the thread that called EnterCriticalSection last time.

  • WaitThr is the ID of the thread that found the critical section that another thread owned and waited for it last time.

  • TryEnThr is the ID of the thread that called TryEnterCriticalSection last time.

  • LeaveThr is the ID of the thread that called LeaveCriticalSection last time

  • EnterCnt is the count of EnterCriticalSection.

  • WaitCnt is the contention count.

See also

!ntsdexts.locks

Displaying a Critical Section

Critical Section Time Outs (user mode)