Good afternoon
I have a kmdf driver that can read and write to a file.
Through a custom application I can send IOCTL requests. If I send a request from one process to write, from another process to read, everything is fine. But if I send a read request and then a write request, both requests do not complete and seem to hang.
This is the loop I have in my custom application

do
    {
        printf("Enter command (read/write): ");
        scanf("%s", command);

        bufLength = 25;

        if (strcmp(command, "read") == 0)
        {
            if (!DoFileRead(hDevice, bufLength))
            {
                break;
            }
        }
        else if (strcmp(command, "write") == 0)
        {
            if (!DoFileWrite(hDevice, bufLength))
            {
                break;
            }
        }
    }
    WHILE(TRUE);

Handler code in the driver

VOID
FileEvtIoDeviceControl(
    IN WDFQUEUE         Queue,
    IN WDFREQUEST       Request,
    IN size_t           OutputBufferLength,
    IN size_t           InputBufferLength,
    IN ULONG            IoControlCode
    )
{
    NTSTATUS            status = STATUS_SUCCESS;
    NTSTATUS            rstatus = STATUS_SUCCESS;
    IO_STATUS_BLOCK             ioStatus;
    PCHAR inBuf = NULL;
    PCHAR outBuf = NULL;
    PCHAR               data = "this String is from Device Driver !!!";
    ULONG               datalen = (ULONG) strlen(data)+1;
    PCHAR               buffer = NULL;
    PREQUEST_CONTEXT    reqContext = NULL;
    size_t               bufSize;
    PCONTROL_DEVICE_EXTENSION   devExt;
    FILE_POSITION_INFORMATION   position;
    ULONG_PTR                   bytesWritten = 0;
    ULONG_PTR                   bytesRead = 0;
    WDFDEVICE device;
    UNREFERENCED_PARAMETER( Queue );
    PAGED_CODE();
    switch (IoControlCode)
    {
        case IOCTL_WRITE:
        status = WdfRequestRetrieveInputBuffer(Request, 0, &inBuf, &bufSize);
        if(!NT_SUCCESS(status)) {
            status = STATUS_INSUFFICIENT_RESOURCES;
            break;
        }
        devExt = ControlGetData(WdfIoQueueGetDevice(Queue));
        if(devExt->FileHandle) {
            position.CurrentByteOffset.QuadPart = 0;

            status = ZwSetInformationFile(devExt->FileHandle,
                                    &ioStatus,
                                    &position,
                                    sizeof(FILE_POSITION_INFORMATION),
                                    FilePositionInformation);
            if (NT_SUCCESS(status))
            {

                status = ZwWriteFile(devExt->FileHandle, NULL,
                                    NULL, NULL, &ioStatus, inBuf,
                                    (ULONG)InputBufferLength, 0, NULL);
                if (!NT_SUCCESS(status))
                {
                    //...
                }
                status = ioStatus.Status;
                bytesWritten =  ioStatus.Information;
            }
        }
        WdfRequestCompleteWithInformation(Request, status, bytesWritten);
        if (devExt->PendingRequest) {
            rstatus = WdfRequestRetrieveOutputBuffer(devExt->PendingRequest, 0, &outBuf, &bufSize);
            if (!NT_SUCCESS(rstatus))
            {
                WdfRequestComplete(devExt->PendingRequest, rstatus);
                return;
            }
            position.CurrentByteOffset.QuadPart = 0;
            rstatus = ZwSetInformationFile(devExt->FileHandle,
                                        &ioStatus,
                                        &position,
                                        sizeof(FILE_POSITION_INFORMATION),
                                        FilePositionInformation);
            if (NT_SUCCESS(rstatus))
            {
                rstatus = ZwReadFile(devExt->FileHandle,NULL,NULL,NULL,
                                    &ioStatus,outBuf,(ULONG)OutputBufferLength,
                                    0,NULL
                );
                if (!NT_SUCCESS(rstatus))
                {
                      //...
                }
                else
                {
                    WdfRequestCompleteWithInformation(devExt->PendingRequest, rstatus, ioStatus.Information);
                    devExt->isDataAdded = FALSE;
                    devExt->PendingRequest = NULL;
                }
            }
        } else {
            devExt->isDataAdded = TRUE;
        }
        return;
        break;
    case IOCTL_READ:
        status = WdfRequestRetrieveOutputBuffer(Request, 0, &outBuf, &bufSize);
        if(!NT_SUCCESS(status)) {
            WdfRequestComplete(Request, status);
            return;
        }
        devExt = ControlGetData(WdfIoQueueGetDevice(Queue));
        if(devExt->FileHandle) 
        {
            if (!devExt->isDataAdded)
            {
                if (!devExt->PendingRequest)
                {
                    KdPrint(("FileEvtIoRead, data not available...n"));
                    devExt->PendingRequest = Request;
                }
                else
                {
                    WdfRequestComplete(Request, STATUS_UNSUCCESSFUL);
                }
                return;
            }
            position.CurrentByteOffset.QuadPart = 0;
            status = ZwSetInformationFile(devExt->FileHandle,
                                &ioStatus,
                                &position,
                                sizeof(FILE_POSITION_INFORMATION),
                                FilePositionInformation);
            if (NT_SUCCESS(status)) {
                status = ZwReadFile (devExt->FileHandle,NULL,NULL,NULL,
                                    &ioStatus,outBuf,(ULONG)OutputBufferLength,
                                    0,NULL
                                    );
                if (!NT_SUCCESS(status)) {
                    //...
                }
                else
                {
                    devExt->isDataAdded = FALSE;
                }
                status = ioStatus.Status;
                bytesRead = ioStatus.Information;
            }
        }
        WdfRequestSetInformation(Request, bytesRead);
        break;
    default:
        status = STATUS_INVALID_DEVICE_REQUEST;
        break;
    }
    WdfRequestComplete( Request, status);

}

Tried changing the end of the queries, but nothing works