diff --git a/dlls/ntoskrnl.exe/ntoskrnl.exe.spec b/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
index 2d1c82663d6..bdf2a4463c0 100644
--- a/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
+++ b/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
@@ -146,7 +146,7 @@
 @ stub ExFreeToPagedLookasideList
 @ stub ExGetCurrentProcessorCounts
 @ stub ExGetCurrentProcessorCpuUsage
-@ stub ExGetExclusiveWaiterCount
+@ stdcall ExGetExclusiveWaiterCount(ptr)
 @ stub ExGetPreviousMode
 @ stub ExGetSharedWaiterCount
 @ stdcall ExInitializeNPagedLookasideList(ptr ptr ptr long long long long)
diff --git a/dlls/ntoskrnl.exe/sync.c b/dlls/ntoskrnl.exe/sync.c
index c8cae7dd899..823ff2b5874 100644
--- a/dlls/ntoskrnl.exe/sync.c
+++ b/dlls/ntoskrnl.exe/sync.c
@@ -1087,3 +1087,22 @@ void WINAPI ExReleaseResourceLite( ERESOURCE *resource )
 {
     ExReleaseResourceForThreadLite( resource, (ERESOURCE_THREAD)KeGetCurrentThread() );
 }
+
+/***********************************************************************
+ *           ExGetExclusiveWaiterCount   (NTOSKRNL.EXE.@)
+ */
+ULONG WINAPI ExGetExclusiveWaiterCount( ERESOURCE *resource )
+{
+    ULONG count;
+    KIRQL irql;
+
+    TRACE("resource %p.\n", resource);
+
+    KeAcquireSpinLock( &resource->SpinLock, &irql );
+
+    count = resource->NumberOfExclusiveWaiters;
+
+    KeReleaseSpinLock( &resource->SpinLock, irql );
+
+    return count;
+}
diff --git a/include/ddk/wdm.h b/include/ddk/wdm.h
index 41c462f4a75..241f6d695ed 100644
--- a/include/ddk/wdm.h
+++ b/include/ddk/wdm.h
@@ -1524,6 +1524,7 @@ void      WINAPI ExDeleteNPagedLookasideList(PNPAGED_LOOKASIDE_LIST);
 NTSTATUS  WINAPI ExDeleteResourceLite(ERESOURCE*);
 void      WINAPI ExFreePool(PVOID);
 void      WINAPI ExFreePoolWithTag(PVOID,ULONG);
+ULONG     WINAPI ExGetExclusiveWaiterCount(ERESOURCE*);
 void      WINAPI ExInitializeNPagedLookasideList(PNPAGED_LOOKASIDE_LIST,PALLOCATE_FUNCTION,PFREE_FUNCTION,ULONG,SIZE_T,ULONG,USHORT);
 NTSTATUS  WINAPI ExInitializeResourceLite(ERESOURCE*);
 PSLIST_ENTRY WINAPI ExInterlockedPopEntrySList(PSLIST_HEADER,PKSPIN_LOCK);