Hi,

Can anyone please tell, When we use modprobe, which path it looks in to find the .ko modules. Because i am using like this

modprobe ./a.ko

it is giving me following error:

FATAL: Module ./a.ko not found

The documentation says that it looks into /lib/modules, i have copied the necessary .ko file into the above mentioned directory but still i am getting the error

Module: ./a.ko not found

Can anybody tell which path the modprobe looks into or what should i do to run modprobe?

Regards,
dinky

modprobe looks into /lib/modules/<kernel version> for modules to load
If you want to insert a module into the kernel from the current directory use

Hi,

Yes that is true. I have put the .ko module into /lib/modules/'uname -r'
folder. But Still Modprobe is giving the same error. Am i missing some thing?

Regards,
dinky

Take a look at the dmesg output to see if you find what the problem is.
Also you can try the insmod command, or run before modprobe
to adjust module dependencies in modules.dep

Hi,

I tried depmod -a
before running modprobe but still getting same problem. Do i need some special configuration in kernel config file?

The problem with insmod is as follows:

I have two modules a.ko and b.ko. b.ko is using the APIs of a.ko. I have exported the APIs from a.ko that i want to use in b.ko, But when i am doing insmod ./a.ko,

it is inserting it successfully but when i run

insmod ./b.ko

i am getting the following error:

insmod: error inserting 'b.ko': -1 unknown symbol in module and when i am using dmesg

i am getting the following info

b: Unknown symbol register_driver

SO here i am stuck. Any help will be appreciated. so thats why i tried using modprobe. What should i do to run it successfully?

Regards,
dinky

I think that the correct place to put not standard kernel modules is /lib/modules/`uname -r`/misc
And you can run
to see if it helps

Hi,

I tried
depmod -aev|grep register_driver

its output is nothing.

But also in /lib/modules/'uname -r'

there is no 'misc' folder exists in above mentioned directory, shall i create this folder misc or what should i do? really got stuck..

Regards,
dinky

and one question more why my module dependencies are not existing in modules.dep file??? any idea

Well, I don't think the misc directory is important, as depmod will find all the modules under /lib/modules/`uname -r` and build the necessary dependencies.
So I guess that the b.ko does not have any reference to symbols from the a.ko. You can see if that's the case grepping a.ko or b.ko in modules.dep:
If the dependencies exist you can unload a.ko and try to load b.ko directly to see if it loads also a.ko.

Hi bathory,

First very-2 thanks for supporting me. Yeah I have put the a.ko and b.ko files in /lib/modules/'uname-r' and then run the depmod -a and i am able to see dependencies in modules.dep But when i tried

modprobe ./b.ko

it is giving me error

FATAL: Module ./b.ko not found

what should i change that this modprobe will work.

Regards,
dinky

For what kernel version are you writing these modules. I'm not a programmer myself, but the output of
for a 2.6.x kernel, does not return any plain "register_driver" symbol

Hi bathory,

when i executed this

/proc/kallsyms | grep register_driver

i got the following output

f8def9a0 r __ksymtab_register_driver [a.ko]
f8def9e7 r __kstrtab_register_driver [a.ko]
f8def9bc r __kcrctab_register_driver [a.ko]
de21cf89 a __crc_register_driver [a.ko]
f8def130 T register_driver [a.ko]

I am using the kernel version 2.6.27.18-custom.

I do not know why this modprobe is not working...

regards,
dinky

Doh, I don't know either, since the symbol is exported.
Run
and see if it knows it depends on a.ko.
As a last resort try to force load it and see what happens

Hi Bathory,

Thanks for your support. i checked the modinfo ./b.ko

it is giving the following module information:

filename: ./b.ko
license: GPL
author: dinky
depends:
vermagic: 2.6.27.18-custom SMP mod_unload modversions 386


But in depends row, it does not know anything. why in depends it is not showing that it depends on a.

regards,
dinky

You should be able to answer to this, as you are the programmer