Unknown symbol device_create_file

[ml01172]

Hi,

I am trying to write a driver for my barcode reader, and I am in the
middle of the process. At the current state, I am testing it and
compiler reports no errors. But once I try to insert it as module, it
reports the following error:
insmod: error inserting 'usbTest.ko': -1 Unknown symbol in module

/var/log/syslog reports the following lines:
Mar 19 22:54:45 darko kernel: Symbol usb_register_driver is being used
by a non-GPL module, which will not be allowed in the future
Mar 19 22:54:45 darko kernel: Please see the file Documentation/
feature-removal-schedule.txt in the kernel source tree for more
details.
Mar 19 22:54:45 darko kernel: usbTest: Unknown symbol
device_create_file
Mar 19 22:54:45 darko kernel: Symbol usb_deregister is being used by a
non-GPL module, which will not be allowed in the future
Mar 19 22:54:45 darko kernel: Please see the file Documentation/
feature-removal-schedule.txt in the kernel source tree for more
details.
Mar 19 22:54:45 darko kernel: usbTest: Unknown symbol
device_remove_file

Though I don't know why usb_register is said to be not allowed in the
future, at the moment I am more interested in how it can't find the
device_remove_file and device_create symbols if:
1. compiler reports no errors;
2. /proc/kallsyms enlists them:
...
ffffffff803cd65b T device_create_file
ffffffff803cd694 T device_remove_file
...

Am I supposed to link differently or something, I am not sure, but I
know my deadline is due

This is what compiler says:

make -C /usr/src/linux M=/usr/home/ml01172/DeviceDrivers/usbTest
modules
make[1]: Entering directory `/usr/src/linux-2.6.19.2'
Building modules, stage 2.
MODPOST 1 modules
make[1]: Leaving directory `/usr/src/linux-2.6.19.2'

As you can see, my kernel is 2.6.19.2, so if you can help me, please
do so

And yes, my Makefile is as following:

ifneq ($(KERNELRELEASE),)
obj-m := usbTest.o

else
KERNELDIR ?= /usr/src/linux
PWD := $(shell pwd)

default:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules

clean:
rm -rf *.ko *.o *~

endif


Thanks

Darko

[digvijay.gahlot]

Add MODULE_LICENSE("GPL") in your module code and then recompile it.
i.e.
MODULE_LICENSE("GPL");

[ml01172]

Thanks a lot, that seems to help. Actually, although I didn't know those things are related, I had already tried to insert that statement, but as far as I remember (I'm pretty sure) it rejected it as unknown during compilation. Now I tried, and it compiled successfully, plus the symbol (not this one I've talked about, but another one I switched to (with the same problem though)) is now recognized.

Thank you a lot,

Darko