systemtap

[fengggli]

• https://wiki.ubuntu.com/Kernel/Systemtap#Where_to_get_debug_symbols_for_kernel_X.3F
• https://bugs.launchpad.net/ubuntu/+source/systemtap/+bug/1830726

[fengggli]

install

• download source

  wget https://sourceware.org/systemtap/ftp/releases/systemtap-4.1.tar.gz

• prepare elfutils
  • sudo apt-get install elfutils python-setuptools
  • apt-get source elfutils
  • (in systemtap source tree)/configure --prefix=${HOME}/software/install/ --with-elfutils=${HOME}/software/elfutils-0.165
• make & make install
• debug kernel install (from https://wiki.ubuntu.com/Kernel/Systemtap#Where_to_get_debug_symbols_for_kernel_X.3F):

  
  sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys C8CAB6595FDFF622 
  codename=$(lsb_release -c | awk  '{print $2}')
  sudo tee /etc/apt/sources.list.d/ddebs.list << EOF
  deb http://ddebs.ubuntu.com/ ${codename}      main restricted universe multiverse
  deb http://ddebs.ubuntu.com/ ${codename}-security main restricted universe multiverse
  deb http://ddebs.ubuntu.com/ ${codename}-updates  main restricted universe multiverse
  deb http://ddebs.ubuntu.com/ ${codename}-proposed main restricted universe multiverse
  EOF

sudo apt-get update sudo apt-get install linux-image-$(uname -r)-dbgsym

* test installation

sudo env "PATH=$PATH" stap -v -e 'probe vfs.read {printf("read performed\n"); exit()}'

* Use script

sudo env "PATH=$PATH" stap test.tap -x 7931

// better one ps aux|grep mcas|head -1 |awk '{print $2}' | sudo env "PATH=$PATH" xargs -I{} stap test.tap -x {}

* How to write probes: https://linux.die.net/man/5/stapprobes

[fengggli]

Fixd by using?: (not actually, this was an error in my script)

# apt-get install -y elfutils

for file in `find /usr/lib/debug -name '*.ko' -print`
do
        buildid=`eu-readelf -n $file| grep Build.ID: | awk '{print $3}'`
        dir=`echo $buildid | cut -c1-2`
        fn=`echo $buildid | cut -c3-`
        mkdir -p /usr/lib/debug/.build-id/$dir
        ln -s $file /usr/lib/debug/.build-id/$dir/$fn
        ln -s $file /usr/lib/debug/.build-id/$dir/${fn}.debug
done