verify kernel compile macro in running linux

How to check whether a kernel compile macro is enabled on a running linux machine?

root@babu-VirtualBox:~/tools/stk_corruption/stk_overflow_lkm# grep OVERFLOW /boot/config-3.13.5
CONFIG_HAVE_DEBUG_STACKOVERFLOW=y
# CONFIG_DEBUG_STACKOVERFLOW is not set
root@babu-VirtualBox:~/tools/stk_corruption/stk_overflow_lkm#

How to edit boot options during linux booting?

The following steps worked for me in a Virtualbox Ubuntu VM:

• During the boot up menu, select the kernel version you want to boot with: 

                        

                        

• Press 'e' to enable editing of this line:

                        

• Go to "linux" bootline & add the boot options. I am adding slub_debug option in my screen:

                        

                        

• Do these boot options get retained across reboot?

          No. 

How to - Linux Kernel Compilation in Ubuntu VM/VirtualBox

I recently compiled linux kernel in a Virtualbox VM. Here are the steps I used to compile a custom linux kernel. These steps worked for me in Ubuntu 13.10 distribution.


Check the linux version of your VM:

babu@babu-VirtualBox:~$ uname -a

Linux babu-VirtualBox 3.11.0-12-generic #19-Ubuntu SMP Wed Oct 9 16:12:00 UTC 2013 i686 i686 i686 GNU/Linux

babu@babu-VirtualBox:~$ 

Switch to root mode:

babu@babu-VirtualBox:~$ sudo -s

[sudo] password for babu: 

root@babu-VirtualBox:~#

Download the linux sources for the matching version to /usr/src:

root@babu-VirtualBox:~# cd /usr/src

root@babu-VirtualBox:/usr/src# 

root@babu-VirtualBox:/usr/src# ls

linux-headers-3.11.0-12          vboxguest-4.3.6

linux-headers-3.11.0-12-generic

root@babu-VirtualBox:/usr/src# wget http://www.kernel.org/pub/linux/kernel/v3.x/linux-3.11-tar.bz2

.

.

root@babu-VirtualBox:/usr/src#

In my case, I didn't have tarball for 3.11.0 at http://www.kernel.org/pub/linux/kernel/v3x/. So, I got linux-3.11.tar.bz2 instead:

root@babu-VirtualBox:/usr/src# ls 

linux-headers-3.11.0-12          vboxguest-4.3.6

linux-3.11.tar.bz2  linux-headers-3.11.0-12-generic

root@babu-VirtualBox:/usr/src# 

Extract the source to /usr/src:

root@babu-VirtualBox:/usr/src# tar -xvf linux-3.11.tar.bz2 -C .

.

.

root@babu-VirtualBox:/usr/src# ls

linux-3.11          linux-headers-3.11.0-12          vboxguest-4.3.6

linux-3.11.tar.bz2  linux-headers-3.11.0-12-generic

root@babu-VirtualBox:/usr/src# 

Install compilation tools necessary:

apt-get update

apt-get install gcc

apt-get install make

apt-get install ncurses-*

Select the kernel configuration options you need:

root@babu-VirtualBox:/usr/src# cd linux-3.11/

root@babu-VirtualBox:/usr/src/linux-3.11# make menuconfig

Compile & Install the Kernel:

root@babu-VirtualBox:/usr/src/linux-3.11# make     <-- This step took approximately 2 hours on my dual core VM.

.

.

root@babu-VirtualBox:/usr/src/linux-3.11#  make modules <-- This step took approximately 2 minutes.

.

.

root@babu-VirtualBox:/usr/src/linux-3.11# make modules_install  <-- This step took approximately 10 minutes.

.

.

root@babu-VirtualBox:/usr/src/linux-3.11# make install

.

.

root@babu-VirtualBox:/usr/src/linux-3.11#

Initrd creation & GRUB modification:

I didn't have to create initrd image or a grub entry. An initrd image was already generated in /boot directory & my new image was already in /boot/grub/grub.cfg. I guess grub2 made this step automatic?

Reboot:

/sbin/reboot

Select the new custom created kernel during bootup:

Before the VM boots up, hold the shift key to get the bootloader options list. Then, select "Advanced Options for Ubuntu":

                    

Then in the next menu, select your custom kernel:

                    

Verify that your VM indeed is running the new custom kernel:

babu@babu-VirtualBox:~$ uname -a

Linux babu-VirtualBox 3.11.0 #3 SMP Fri Feb 14 10:54:07 PST 2014 i686 i686 i686 GNU/Linux

babu@babu-VirtualBox:~$ 

Thats it. Hope this helps.

I-nex & lshw - GUI based tool for linux system information

In my earlier post, I covered cli commands that can be used for inspecting system information in linux. I also covered GUI based tools - sysinfo and hardinfo.

I tried two more GUI based tools - I-nex & lshw-gtk. In particular, I liked I-nex. I will try covering these tools later.

sysinfo - GUI based tool for linux system information

In my earlier post, I covered cli commands that can be used for inspecting system information in linux. I also covered GUI based tools - hardinfo. In this post, I will cover sysinfo - a GUI based tool for inspecting system info.

This tool wasn't available by default in Ubuntu 13.10. I installed it manually - apt-get install sysinfo. After this, I typed sysinfo at command prompt to open GUI screen. Below are some screens that help inspect the system info:

hardinfo - GUI based tool for linux system information

In my earlier post, I covered cli commands that can be used for inspecting system information in linux. I also covered GUI based tools - sysinfo. In this post, I will cover hardinfo - a GUI based tool for inspecting system info.

This tool wasn't available by default in Ubuntu 13.10. I installed it manually - apt-get install hardinfo. After this, I typed hardinfo at command prompt to open GUI screen. Below are some screens that help inspect the system info:

Linux System Info Commands

In this post, I will cover the cli commands that can be used to get system information. I will also cover some GUI tools in my upcoming posts. Embedded systems do not have GUI capabilities & hence the following commands would be handy despite the availability of various GUI based tools.

CPU Info

How many processors does the system have?

Method1:

      root@babu-VirtualBox:~# grep processor /proc/cpuinfo

      processor     : 0

      processor     : 1

               root@babu-VirtualBox:~# 

Method2:

      root@babu-VirtualBox:~# lscpu | grep "CPU(s):"

      CPU(s):                2

      root@babu-VirtualBox:~# 

What processor make/vendor, speed?

Method1:

      root@babu-VirtualBox:~# grep "model name" /proc/cpuinfo | unique   <-- architecture specific, but works for intel processors

      model name   : Intel(R) Core(TM) i7-3540M CPU @ 3.00GHz
      root@babu-VirtualBox:~# 

Method2:

      root@babu-VirtualBox:~# lscpu | grep Vendor

      Vendor ID:             GenuineIntel
      root@babu-VirtualBox:~# 

      root@babu-VirtualBox:~# lscpu | grep MHz

      CPU MHz:               2976.472
      root@babu-VirtualBox:~# 

What is processor type/architecture?

Method1:

      root@babu-VirtualBox:~# uname -p
      i686
      root@babu-VirtualBox:~# 
      
      root@babu-VirtualBox:~# uname -m   
      i686

      root@babu-VirtualBox:~#

Method2:

      root@babu-VirtualBox:~# arch <-- is this installed kernel or processor type?
      i686
      root@babu-VirtualBox:~# 

Method3:

      root@babu-VirtualBox:~# lscpu | grep Architecture
      Architecture:          i686
      root@babu-VirtualBox:~# 

Is the processor 32-bit or 64-bit or both? (this is different from whether the running OS  is 32-bit or 64-bit)

root@babu-VirtualBox:~# lscpu | grep "CPU op"

CPU op-mode(s):        32-bit

root@babu-VirtualBox:~# 

What is the endian-ness of the processor?

root@babu-VirtualBox:~# echo -n I | od -to2 | awk 'FNR==1{ print substr($2,6,1)}'
1
root@babu-VirtualBox:~# 
    <-- 0 if Big endian, 1 if little endian

root@babu-VirtualBox:~# lscpu | grep "Byte"

Byte Order:            Little Endian

root@babu-VirtualBox:~# 

RAM Info

What is the RAM size?

Method1:

      root@babu-VirtualBox:~# cat /proc/meminfo | grep MemTotal

      MemTotal:        1026276 kB
      root@babu-VirtualBox:~# 

Method2:

      root@babu-VirtualBox:~# free -m

                 total              used       free     shared    buffers     cached

Mem:          1002        732        269          0         43        431

-/+ buffers/cache:        257        744

Swap:          510         110        400

root@babu-VirtualBox:~# 

Disk Info

What is the size of the disk?

root@babu-VirtualBox:~# df | grep '^/dev/*' | awk '{s+=$2} END {print s/1048576}'

54.0081          <--- in GB

         root@babu-VirtualBox:~#

root@babu-VirtualBox:~# inxi -D

Drives:    HDD Total Size: 59.6GB (23.8% used) 1: id: /dev/sda model: VBOX_HARDDISK size: 59.6GB 

root@babu-VirtualBox:~#

   
Is the disk SSD or HDD? 
         root@babu-VirtualBox:~# cat /sys/block/sda/queue/rotational
        1         <---  1 for hard disks and 0 for an SSD
         root@babu-VirtualBox:~# 

OS Info

What is the OS distribution?

root@babu-VirtualBox:~# head -n1 /etc/issue
Ubuntu 13.10 \n \l
root@babu-VirtualBox:~# 

root@babu-VirtualBox:~# cat /etc/*-release

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=13.10
DISTRIB_CODENAME=saucy
DISTRIB_DESCRIPTION="Ubuntu 13.10"
NAME="Ubuntu"
VERSION="13.10, Saucy Salamander"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 13.10"
VERSION_ID="13.10"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
root@babu-VirtualBox:~# 

root@babu-VirtualBox:~# lsb_release -a

No LSB modules are available.

Distributor ID:           Ubuntu

Description:   Ubuntu 13.10

Release:         13.10

Codename:    saucy
root@babu-VirtualBox:~# 

What is the linux kernel version?

root@babu-VirtualBox:~# uname -r

3.11.0-12-generic

          root@babu-VirtualBox:~#

root@babu-VirtualBox:~# cat /proc/version 

Linux version 3.13.5 (root@babu-VirtualBox) (gcc version 4.8.1 (Ubuntu/Linaro 4.8.1-10ubuntu9) ) #2 SMP Tue Mar 25 00:40:49 PDT 2014

root@babu-VirtualBox:~# 

Is the OS 32-bit or 64-bit?

root@babu-VirtualBox:~# uname -a
Linux babu-VirtualBox 3.13.5 #1 SMP Wed Mar 5 12:34:20 PST 2014 i686 i686 i686 GNU/Linux
root@babu-VirtualBox:~# 

          <-- In case of 64 bit, we get x86_64. In case of 32-bit, we get i386/i486/i586/i686

root@babu-VirtualBox:~# file /sbin/init   (or any binary in /bin directory)

/sbin/init: ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.24, BuildID[sha1]=0xc0d86a25a7abb14cad4a65a1f7d03605bcbd41f6, stripped

root@babu-VirtualBox:~# 

        <--- 32-bit above indicates 32 bit. 64 bit above indicates 64 bit.

root@babu-VirtualBox:~# getconf LONG_BIT

32         <----- 32, if OS is 32 bit - 64, if OS is 64 bit
root@babu-VirtualBox:~# 

            

More detailed info about the system:

root@babu-VirtualBox:~# lscpu

Architecture	: i686
CPU op-mode(s)	: 32-bit
Byte Order	: Little Endian
CPU(s)	: 2
On-line CPU(s) list	: 0,1
Thread(s) per core	: 1
Core(s) per socket	: 2
Socket(s)	: 1
Vendor ID	: GenuineIntel
CPU family	: 6
Model	: 58
Stepping	: 9
CPU MHz	: 2976.472
BogoMIPS	: 5952.94
L1d cache	: 32K
L1d cache	: 32K
L2d cache	: 6144K

root@babu-VirtualBox:~# 

root@babu-VirtualBox:~# cat /proc/cpuinfo

processor	: 0
vendor_id	: GenuineIntel
cpu family	: 6
model	: 58
model name	: Intel(R) Core(TM) i7-3540M CPU @ 3.00GHz
stepping	: 9
cpu MHz	: 2976.472
cache size	: 6144 KB
physical id	: 0
siblings	: 2
core id	: 0
cpu cores	: 2
apicid	: 0
initial apicid	: 0
fdiv_bug	: no
f00f_bug	: no
coma_bug	: no
fpu	: yes
fpu_exception	: yes
cpuid level	: 5
wp	: yes
flags	: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht nx rdtscp constant_tsc pni ssse3
bogomips	: 5952.94
clflush size	: 64
cache_alignment	: 64
address sizes	: 36 bits physical, 48   bits virtual
power management:
processor	: 1
vendor_id	: GenuineIntel
cpu family	: 6
model	: 58
model name	: Intel(R) Core(TM) i7-3540M CPU @ 3.00GHz
stepping	: 9
cpu MHz	: 2976.472
cache size	: 6144 KB
physical id	: 0
siblings	: 2
core id	: 1
cpu cores	: 2
apicid	: 1
initial apicid	: 1
fdiv_bug	: no
f00f_bug	: no
coma_bug	: no
fpu	: yes
fpu_exception	: yes
cpuid level	: 5
wp	: yes
flags	: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht nx rdtscp constant_tsc pni ssse3
bogomips	: 5952.94
clflush size	: 64
cache_alignment	: 64
address sizes	: 36 bits physical, 48   bits virtual
power management:

root@babu-VirtualBox:~# 

To install inxi tool in ubuntu, I had to do these:

root@babu-VirtualBox:~# inxi -b

System:    Host: babu-VirtualBox Kernel: 3.11.0-12-generic i686 (32 bit) Desktop: N/A Distro: Ubuntu 13.10

Machine:   System: innotek product: VirtualBox version: 1.2 serial: 0 

           Mobo: Oracle model: VirtualBox version: 1.2 serial: 0 Bios: innotek version: VirtualBox date: 12/01/2006

CPU:       Dual core Intel Core i7-3540M CPU (-MCP-) clocked at 2976.472 MHz 

Graphics:  Card: InnoTek Systemberatung VirtualBox Graphics Adapter 

           X.org: 1.14.3 drivers: ati,vboxvideo (unloaded: fbdev,vesa) tty size: 70x24 Advanced Data: N/A for root 

Network:   Card: Intel 82540EM Gigabit Ethernet Controller driver: e1000 

Drives:    HDD Total Size: 59.6GB (23.8% used)

Info:      Processes: 171 Uptime: 8:45 Memory: 300.7/1002.2MB Client: Shell (bash) inxi: 1.9.12 

root@babu-VirtualBox:~#

root@babu-VirtualBox:~# inxi -F

System:    Host: babu-VirtualBox Kernel: 3.11.0-12-generic i686 (32 bit) Desktop: N/A Distro: Ubuntu 13.10

Machine:   System: innotek product: VirtualBox version: 1.2 serial: 0 

           Mobo: Oracle model: VirtualBox version: 1.2 serial: 0 Bios: innotek version: VirtualBox date: 12/01/2006

CPU:       Dual core Intel Core i7-3540M CPU (-MCP-) cache: 6144 KB flags: (nx pae sse sse2 sse3 ssse3) 

           Clock Speeds: 1: 2976.472 MHz 2: 2976.472 MHz

Graphics:  Card: InnoTek Systemberatung VirtualBox Graphics Adapter 

           X.org: 1.14.3 drivers: ati,vboxvideo (unloaded: fbdev,vesa) tty size: 70x24 Advanced Data: N/A for root 

Audio:     Card: Intel 82801AA AC'97 Audio Controller driver: snd_intel8x0 Sound: ALSA ver: k3.11.0-12-generic

Network:   Card: Intel 82540EM Gigabit Ethernet Controller driver: e1000 

           IF: eth0 state: up speed: 1000 Mbps duplex: full mac: 08:00:27:2a:c0:33

Drives:    HDD Total Size: 59.6GB (23.8% used) 1: id: /dev/sda model: VBOX_HARDDISK size: 59.6GB 

Partition: ID: / size: 55G used: 14G (26%) fs: ext4 ID: swap-1 size: 0.54GB used: 0.11GB (21%) fs: swap 

RAID:      No RAID devices detected - /proc/mdstat and md_mod kernel raid module present

Sensors:   None detected - is lm-sensors installed and configured?

Info:      Processes: 171 Uptime: 8:46 Memory: 301.2/1002.2MB Client: Shell (bash) inxi: 1.9.12 

root@babu-VirtualBox:~#

TBD/Advanced/Detailed
lshw, lspci, lsblk, lsusb, lsscsi, lshal, lsraid, lsdev, hwinfo, dmidecode, hdparm, biosdecode