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From:   Praveen Kumar <kpraveen.lkml@gmail.com>
Date:   Wed, 19 Dec 2018 21:01:11 +0530
Message-ID: <CABcWhv4794moz7PZxmzJMySpJnjZR4ikGwHVcicp0-4PWOHmig@mail.gmail.com>
Subject: Re: /proc/modules not showing any output
To:     Greg KH <greg@kroah.com>
Cc:     kernelnewbies@kernelnewbies.org, linux-kernel@vger.kernel.org
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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.