Here's backtrace I collected by attaching gdb to Xorg running without hid_ntrig loaded and then loading hid_ntrig.

Program received signal SIGSEGV, Segmentation fault.
0x0030bbfa in ?? () from /usr/lib/xorg/modules/input/wacom_drv.so
(gdb) backtrace full
#0  0x0030bbfa in ?? () from /usr/lib/xorg/modules/input/wacom_drv.so
No symbol table info available.
#1  0x080c1bda in xf86NewInputDevice (pInfo=0x9d07ae8, pdev=0xbfcc0fc4, 
    enable=1 '\001') at ../../../../hw/xfree86/common/xf86Xinput.c:846
        drv = 0x9d22478
        dev = <value optimized out>
        rval = 8
#2  0x080ca7d9 in device_added (udev_device=<value optimized out>)
    at ../../config/udev.c:194
        path = 0x9d92a08 "/dev/input/event10"
        name = 0x9cc4650 "N-Trig Pen"
        config_info = 0x9d07a60 "udev:/sys/devices/pci0000:00/0000:00:1d.1/usb7/7-2/7-2:1.1/input/input46/event10"
        syspath = 0x81e58bf "xkb"
        tags_prop = <value optimized out>
        key = <value optimized out>
        value = <value optimized out>
        tmp = <value optimized out>
        options = 0x9da47b8
        tmpo = <value optimized out>
        attrs = {product = 0x9cc4660 "N-Trig Pen", 
          vendor = 0x9d07ab8 "N-trig", 
          device = 0x9d8d438 "/dev/input/event10", pnp_id = 0x0, 
          usb_id = 0x9d8d400 "1b96:0001", tags = 0x0, flags = 0}
        dev = 0x0
        set = <value optimized out>
        entry = <value optimized out>
        parent = <value optimized out>
#3  0x080caec2 in wakeup_handler (data=0x0, err=3, read_mask=0x8208320)
    at ../../config/udev.c:255
        udev_fd = <value optimized out>
        udev_device = <value optimized out>
        action = <value optimized out>
#4  0x08073d62 in WakeupHandler (result=3, pReadmask=0x8208320)
    at ../../dix/dixutils.c:419
        i = 3
        j = <value optimized out>
#5  0x080a015a in WaitForSomething (pClientsReady=0x9c41c58)
    at ../../os/WaitFor.c:235
        i = <value optimized out>
        waittime = {tv_sec = 0, tv_usec = 165980}
        wt = 0xbfcc12d4
        timeout = <value optimized out>
        clientsReadable = {fds_bits = {0 <repeats 32 times>}}
        clientsWritable = {fds_bits = {162798544, 162600968, 135302580, 
            -1074004001, -268443654, 134629211, 6345857, 162798544, 
            -1077144872, -1077144952, 136269812, 48, 163856424, -1077145048, 
            134911582, 24, -1077144952, 1, 134694270, 136339532, 136269812, 
            -1077145016, 134921791, 163856424, -1077144952, 1, 134895583, 
            164272528, 15070467, -1077144904, 134894086, 163856424}}
        selecterr = 0
        nready = 0
        devicesReadable = {fds_bits = {0 <repeats 32 times>}}
        now = <value optimized out>
        someReady = <value optimized out>
#6  0x0806f68e in Dispatch () at ../../dix/dispatch.c:367
        clientReady = 0x9c41c58
        result = <value optimized out>
        client = <value optimized out>
        nready = <value optimized out>
        icheck = 0x8207818
        start_tick = <value optimized out>
#7  0x0806284c in main (argc=8, argv=0xbfcc1464, envp=0xbfcc1488)
    at ../../dix/main.c:287
        i = <value optimized out>
        alwaysCheckForInput = {0, 1}