strange IRQL

[alex_s]

I’ve got a bugcheck A while being inside KeWaitForMultipleObjects function with IRQL = 2 (dispatch level). How can it happen ? It can be seen that IRQL is tested before go to wait.

ULONG SignalUser(PUSER_DATA_STRUCT pud)
{
PVOID ObjPtr[2];
NTSTATUS ret_val = 0;

KdPrintEnter((“Enter to %sn”, __FUNCTION__));
if ( KeGetCurrentIrql() > PASSIVE_LEVEL )
{
KdPrintCont((“SignalUser: IRQL > PASSIVE_LEVELn”));
KdPrintReturn((“Return from %sn”, __FUNCTION__));
return 0;
}

if (g_isUserPresent == FALSE)
{
KdPrintCont((“SignalUser: g_isUserPresent == FALSEn”));
KdPrintReturn((“Return from %sn”, __FUNCTION__));
return 0;
}

if (STATUS_SUCCESS != KeWaitForMutexObject(&g_SignalMutex, Executive, KernelMode, FALSE, NULL))
{
KdPrintReturn((“Return from %sn”, __FUNCTION__));
return 0;
}

_BEGIN_BLOCK
RtlCopyMemory(g_pCurrData, pud, sizeof(USER_DATA_STRUCT));
ObjPtr[0] = &g_pWaitItem->hAllow;
ObjPtr[1] = &g_pWaitItem->hDeny;

//inform user space program to read the data
KeSetEvent(g_UserEventObject, 0, FALSE);

// wait for user space to answer
ret_val = KeWaitForMultipleObjects(2, ObjPtr, WaitAny, UserRequest, KernelMode, FALSE, NULL, NULL);

[Taras]

ObjPtr[0] = &g_pWaitItem->hAllow;
ObjPtr[1] = &g_pWaitItem->hDeny;

hAllow, hDeny – are they handle of events? KeWaitForMultipleObjects may operate only with direct pointer to KEVENT struct. If you have handles, you should retrieve direct pointer by call ObReferenceObjectByHandle

[Author]

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