/proc/modules not showing any output

/proc/modules not showing any output

[Praveen Kumar]

Hi All,

Compiled the vanila kernel 4.20.0-rc6 build, and was trying to get
module information, but /proc/modules is not showing any output ( both
on arm64 and x86_64 )

root@ubuntu:~# uname -a
Linux ubuntu 4.20.0-rc6-00082-g65e08c5e8631 #7 SMP PREEMPT Fri Dec 14
15:54:30 IST 2018 aarch64 aarch64 aarch64 GNU/Linux

root@ubuntu:~# cat /proc/modules
root@ubuntu:~#

Tried with older version 4.4.162-78-default modules were properly shown.

Can you please help if there is something which I am missing during
compilation or is there any potential bug here ? Thanks in advance.

Regards,

~Praveen.

Re: /proc/modules not showing any output

[Greg KH]

On Wed, Dec 19, 2018 at 06:52:39PM +0530, Praveen Kumar wrote:
> Hi All,
> 
> Compiled the vanila kernel 4.20.0-rc6 build, and was trying to get
> module information, but /proc/modules is not showing any output ( both
> on arm64 and x86_64 )
> 
> root@ubuntu:~# uname -a
> Linux ubuntu 4.20.0-rc6-00082-g65e08c5e8631 #7 SMP PREEMPT Fri Dec 14
> 15:54:30 IST 2018 aarch64 aarch64 aarch64 GNU/Linux
> 
> root@ubuntu:~# cat /proc/modules
> root@ubuntu:~#
> 
> Tried with older version 4.4.162-78-default modules were properly shown.
> 
> Can you please help if there is something which I am missing during
> compilation or is there any potential bug here ? Thanks in advance.

Are you sure your .config file has enabled modules?  Have you actually
loaded any?  If you do not load any, nothing will show up in that proc
file :)

thanks,

greg k-h

Re: /proc/modules not showing any output

[Praveen Kumar]

On Wed, Dec 19, 2018 at 8:36 PM Greg KH <greg@kroah.com> wrote:
>
> On Wed, Dec 19, 2018 at 06:52:39PM +0530, Praveen Kumar wrote:
> > Hi All,
> >
> > Compiled the vanila kernel 4.20.0-rc6 build, and was trying to get
> > module information, but /proc/modules is not showing any output ( both
> > on arm64 and x86_64 )
> >
> > root@ubuntu:~# uname -a
> > Linux ubuntu 4.20.0-rc6-00082-g65e08c5e8631 #7 SMP PREEMPT Fri Dec 14
> > 15:54:30 IST 2018 aarch64 aarch64 aarch64 GNU/Linux
> >
> > root@ubuntu:~# cat /proc/modules
> > root@ubuntu:~#
> >
> > Tried with older version 4.4.162-78-default modules were properly shown.
> >
> > Can you please help if there is something which I am missing during
> > compilation or is there any potential bug here ? Thanks in advance.
>
> Are you sure your .config file has enabled modules?  Have you actually
> loaded any?  If you do not load any, nothing will show up in that proc
> file :)
>

Thanks Greg for the reply.
I think I did compile with enabled modules.
kern-xen-dev:/mnt/kernel/linux # cat .config | grep MODULE
CONFIG_MODULES_USE_ELF_RELA=y
CONFIG_ARCH_HAS_STRICT_MODULE_RWX=y
CONFIG_STRICT_MODULE_RWX=y
CONFIG_MODULES=y                              <<<<<<<<
# CONFIG_MODULE_FORCE_LOAD is not set
CONFIG_MODULE_UNLOAD=y
CONFIG_MODULE_FORCE_UNLOAD=y
# CONFIG_MODULE_SRCVERSION_ALL is not set
# CONFIG_MODULE_SIG is not set
# CONFIG_MODULE_COMPRESS is not set
CONFIG_MODULES_TREE_LOOKUP=y

I added a new kernel module and was able to see the module added.

kern-xen-dev:/mnt/kernel/linuxfs # insmod linuxfs.ko
kern-xen-dev:/mnt/kernel/linuxfs # cat /proc/modules
linuxfs 16384 0 - Live 0xffffffffc01c1000 (O)

I think, on my test machine, by default, there are many modules which
get added during boot up, which with vanilla kernel is not happening.
Thanks for your input.

Regards,

~Praveen.

Re: /proc/modules not showing any output

[Praveen Kumar]

On Wed, Dec 19, 2018 at 9:28 PM Aruna Hewapathirane
<aruna.hewapathirane@gmail.com> wrote:
>
> <snip>
>>
>> I think, on my test machine, by default, there are many modules which
>> get added during boot up, which with vanilla kernel is not happening.
>> Thanks for your input.
>>
>> Regards,
>>
>> ~Praveen.
>>
>
> What does lsmod show you in the vanilla kernel ? If you want the same modules to load in the vanilla
> kernel folow steps given below:
>
> 1 -boot into the older 4.4.162-78-defaultkernel
> 2 - change into the vanilla kernel source 4.20.0-rc6 builddirectory
> 3 - $ lsmod > lsmod.txt
> 4 - $ make LSMOD="lsmod.txt" localmodconfig
>
> Boot into your newly compiled vanilla kernel and run lsmod and smile :-)
>
> Hope this helps - Aruna
>
Thanks Aruna. This helps.