Linux Kernel SysRq

SysRq key can be enabled with the following command:

echo 1 > /proc/sys/kernel/sysrq

causes a kernel panic 

echo c > /proc/sysrq-trigger

 equivalent to the key combination Alt+SysRq+B which reboots the machine.

echo b > /proc/sysrq-trigger

routing table

from 192.168.1.x to 192.168.123.x

root@EbMajor:~# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         192.168.123.254 0.0.0.0         UG    0      0        0 eth0
192.168.1.0     *               255.255.255.0   U     0      0        0 br-lan
192.168.123.0   *               255.255.255.0   U     0      0        0 eth0

kernel device tree makefile

arch/arm/boot/dts/Makefile
dtb-$(CONFIG_ARCH_AT91) += at91rm9200ek.dtb

ssh add user

~/.ssh/config

Host xxx.git.com
    HostName xxx.git.com
    Port xxxx
    User xxx
Host xxx-git
   Port xxxx
   User xxxx
  HostName xxx.git.com

Samba on Ubuntu 14.04 / 16.04

for 14.04

http://ubuntuhandbook.org/index.php/2014/05/ubuntu1404-file-sharing-samba/

add samba user

sudo smbpasswd -a username

for 16.04

https://www.linuxbabe.com/ubuntu/install-samba-server-file-share

https://ubuntu.com/tutorials/install-and-configure-samba#1-overview

ubuntu 14.04 - remote desktop - No security types supported

* Problem
- TightVNC
Server sent security types, but we do not support any of their

* Solution
type the command on Terminal
gsettings set org.gnome.Vino require-encryption false

patch to upstream kernel, hostap, and wireless regdb

1. Seetup .gitconfig

a. Edit Home_root/.gitconfig (~/.gitconfig)

b. Check user email and name

c. Add sendemail

i. [sendemail]

ii. smtpserver = mail.xxx.com

iii. smtpdomain = mail.xxx.com

iv. from = xxx@xxx.com (email address)

2. Find the maintainer

a. scripts/get_maintainer.pl –f file

i. kernel/linux$ ./scripts/get_maintainer.pl -f xxx.c

Felipe Balbi <balbi@ti.com> (maintainer:USB GADGET/PERIPH...)

Greg Kroah-Hartman <gregkh@linuxfoundation.org> (supporter:USB SUBSYSTEM)

linux-usb@vger.kernel.org (open list:USB GADGET/PERIPH...)

linux-kernel@vger.kernel.org (open list)

b. scripts/get_maintainer.pl  xxx.patch

3. pull down the code

a. git clone git://xxxxx/linux.git

4. make change/commit with useful description

a. git add –A

b. git commit -s

ex) xxx: xxxxx

5. Generate the patch

a. ath10k

git format-patch --patience -M -C --subject-prefix="PATCH" --to="ath10k@lists.infradead.org" --to="kvalo@qca.qualcomm.com" --cc="linux-wireless@vger.kernel.org" HEAD~

b. mac80211

git format-patch --patience -M -C --subject-prefix="PATCH" --to="linux-wireless@vger.kernel.org" --to="johannes@sipsolutions.net"  --cc="johannes.berg@intel.com" HEAD~

c. hostap
git format-patch --patience -M -C --subject-prefix="PATCH" --to="hostap@lists.infradead.org" HEAD~

d. usb
git format-patch --patience -M -C --subject-prefix="PATCH" --to="Greg Kroah-Hartman <gregkh@linuxfoundation.org>" --to="Felipe Balbi <balbi@ti.com>" --cc="linux-usb@vger.kernel.org" --cc="linux-kernel@vger.kernel.org" HEAD~

e. upload 2nd patch

git format-patch --patience -M -C --subject-prefix="PATCH v2" --thread --to="xxx"  --cc="xxxx" HEAD~

f. multiple patches with cover letter
git format-patch --cover-letter

git format-patch --patience -M -C --subject-prefix="PATCH v2" --thread --to="hostap@lists.infradead.org" HEAD~15 --cover-letter

g. wireless-regdb
git format-patch --patience -M -C --subject-prefix="PATCH" --to="wireless-regdb@lists.infradead.org" --cc="linux-wireless@vger.kernel.org" HEAD~

6. #sends off the mail

 a. install git-email: sudo apt-get install git-email

b. git send-email 0001-xxxx.patch

Who should the emails be sent to? //just enter

Message-ID to be used as In-Reply-To for the first email? //just enter

Send this email? ([y]es|[n]o|[q]uit|[a]ll): y

c. to suppress confirmation message: git config --global sendemail.confirm auto

* command line example
git send-email --suppress-cc=all --smtp-server=mail.server.com --smtp-server-port=1234 --smtp-encryption=tls --smtp-user=ebmajor --to=receiver@mail.com --cc=ccee@mail.com 0001-fix-patch-file.patch

* multiple patch to send
git send-email *.patch

$ git config --global sendemail.smtpserver smtp.gmail.com
$ git config --global sendemail.smtpserverport 587
$ git config --global sendemail.smtpencryption tls
$ git config --global sendemail.smtpuser your_email@gmail.com
$ git config --global sendemail.smtppass your_password

--------------------

$ git show --format=fixes a66b98db570a638afd909459e1e6bfa272344bd3 | head -1

Fixes: a66b98db570a ("mac80211: fix rx->key NULL dereference during mic failure")

How to configure it is documented in SubmittingPatches:

https://www.kernel.org/doc/html/latest/process/submitting-patches.html#describe-your-changes

*** trouble shooting
STARTTLS failed! SSL connect attempt failed error:1416F086:STARTTLS failed! SSL routines:tls_process_server_certificate:certificate verify failed at /usr/lib/git-core/git-send-email
- set  smtpsslcertpath = /etc/ssl/certs in git config (~/.gitconfig)