Add ros2_tracing support

[carlossvg]

• Add ubuntu user to the tracing group => https://gitlab.com/ros-tracing/ros2_tracing#tracing
• Fix LTTng kernel tracer installation failure => See below
• Add ros2_tracing and dependencies => https://github.com/ros-realtime/ros-realtime-rpi4-image/blob/master/focal-rt-ros2/rootfs/setup/phase1.sh#L61

LTTng kernel tracer installation failure

Note: This issue it's probably might be related to https://github.com/ros-realtime/linux-real-time-kernel-builder but I decided to report it here so we are able to validate the fix with the resulting image.

The installation of the LTTng kernel tracer fails with the following error message:

sudo apt-get install lttng-modules-dkms
Reading package lists... Done
Building dependency tree       
Reading state information... Done
lttng-modules-dkms is already the newest version (2.12.5-1ubuntu2~20.04.1).
0 upgraded, 0 newly installed, 0 to remove and 110 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] Y
Setting up lttng-modules-dkms (2.12.5-1ubuntu2~20.04.1) ...
Removing old lttng-modules-2.12.5 DKMS files...

------------------------------
Deleting module version: 2.12.5
completely from the DKMS tree.
------------------------------
Done.
Loading new lttng-modules-2.12.5 DKMS files...
Building for 5.4.140-rt64
Building initial module for 5.4.140-rt64
ERROR (dkms apport): kernel package linux-headers-5.4.140-rt64 is not supported
Error! Bad return status for module build on kernel: 5.4.140-rt64 (aarch64)
Consult /var/lib/dkms/lttng-modules/2.12.5/build/make.log for more information.
dpkg: error processing package lttng-modules-dkms (--configure):
 installed lttng-modules-dkms package post-installation script subprocess returned error exit status 10
Errors were encountered while processing:
 lttng-modules-dkms
E: Sub-process /usr/bin/dpkg returned an error code (1)

Checking the log:

cat /var/lib/dkms/lttng-modules/2.12.5/build/make.log
DKMS make.log for lttng-modules-2.12.5 for kernel 5.4.140-rt64 (aarch64)
Fri Mar  4 16:10:56 CET 2022
make: Entering directory '/usr/src/linux-headers-5.4.140-rt64'
  CC [M]  /var/lib/dkms/lttng-modules/2.12.5/build/lttng-ring-buffer-client-discard.o
  CC [M]  /var/lib/dkms/lttng-modules/2.12.5/build/lib/ringbuffer/ring_buffer_backend.o
  CC [M]  /var/lib/dkms/lttng-modules/2.12.5/build/tests/probes/lttng-test.o
/var/lib/dkms/lttng-modules/2.12.5/build/probes/Kbuild:166: Files ./fs/btrfs/*.h not found. Probe "btrfs" is disabled. Use full kernel source tree to enable it.
/var/lib/dkms/lttng-modules/2.12.5/build/probes/Kbuild:177: Files ./fs/ext4/*.h not found. Probe "ext4" is disabled. Use full kernel source tree to enable it.
/var/lib/dkms/lttng-modules/2.12.5/build/probes/Kbuild:208: File ./drivers/base/regmap/trace.h not found. Probe "regmap" is disabled. Need Linux 4.1+ kernel source tree to enable it.
  CC [M]  /var/lib/dkms/lttng-modules/2.12.5/build/probes/lttng-probe-sched.o
/bin/sh: 1: scripts/basic/fixdep: Exec format error
make[2]: *** [scripts/Makefile.build:270: /var/lib/dkms/lttng-modules/2.12.5/build/tests/probes/lttng-test.o] Error 2
make[2]: *** Deleting file '/var/lib/dkms/lttng-modules/2.12.5/build/tests/probes/lttng-test.o'
make[1]: *** [scripts/Makefile.build:519: /var/lib/dkms/lttng-modules/2.12.5/build/tests] Error 2
make[1]: *** Waiting for unfinished jobs....
  CC [M]  /var/lib/dkms/lttng-modules/2.12.5/build/probes/lttng-probe-irq.o
/bin/sh: 1: scripts/basic/fixdep: Exec format error
make[1]: *** [scripts/Makefile.build:270: /var/lib/dkms/lttng-modules/2.12.5/build/lttng-ring-buffer-client-discard.o] Error 2
make[1]: *** Deleting file '/var/lib/dkms/lttng-modules/2.12.5/build/lttng-ring-buffer-client-discard.o'
  CC [M]  /var/lib/dkms/lttng-modules/2.12.5/build/probes/lttng-probe-timer.o
/bin/sh: 1: scripts/basic/fixdep: Exec format error
make[2]: *** [scripts/Makefile.build:270: /var/lib/dkms/lttng-modules/2.12.5/build/lib/ringbuffer/ring_buffer_backend.o] Error 2
make[2]: *** Deleting file '/var/lib/dkms/lttng-modules/2.12.5/build/lib/ringbuffer/ring_buffer_backend.o'
make[1]: *** [scripts/Makefile.build:519: /var/lib/dkms/lttng-modules/2.12.5/build/lib] Error 2
  CC [M]  /var/lib/dkms/lttng-modules/2.12.5/build/probes/lttng-probe-kmem.o
/bin/sh: 1: scripts/basic/fixdep: Exec format error
make[2]: *** [scripts/Makefile.build:270: /var/lib/dkms/lttng-modules/2.12.5/build/probes/lttng-probe-sched.o] Error 2
make[2]: *** Deleting file '/var/lib/dkms/lttng-modules/2.12.5/build/probes/lttng-probe-sched.o'
make[2]: *** Waiting for unfinished jobs....
/bin/sh: 1: scripts/basic/fixdep: Exec format error
make[2]: *** [scripts/Makefile.build:270: /var/lib/dkms/lttng-modules/2.12.5/build/probes/lttng-probe-irq.o] Error 2
make[2]: *** Deleting file '/var/lib/dkms/lttng-modules/2.12.5/build/probes/lttng-probe-irq.o'
/bin/sh: 1: scripts/basic/fixdep: Exec format error
make[2]: *** [scripts/Makefile.build:270: /var/lib/dkms/lttng-modules/2.12.5/build/probes/lttng-probe-timer.o] Error 2
make[2]: *** Deleting file '/var/lib/dkms/lttng-modules/2.12.5/build/probes/lttng-probe-timer.o'
/bin/sh: 1: scripts/basic/fixdep: Exec format error
make[2]: *** [scripts/Makefile.build:270: /var/lib/dkms/lttng-modules/2.12.5/build/probes/lttng-probe-kmem.o] Error 2
make[2]: *** Deleting file '/var/lib/dkms/lttng-modules/2.12.5/build/probes/lttng-probe-kmem.o'
make[1]: *** [scripts/Makefile.build:519: /var/lib/dkms/lttng-modules/2.12.5/build/probes] Error 2
make: *** [Makefile:1765: /var/lib/dkms/lttng-modules/2.12.5/build] Error 2
make: Leaving directory '/usr/src/linux-headers-5.4.140-rt64'

uname -a
Linux ubuntu 5.4.140-rt64 #1 SMP PREEMPT_RT Sat Oct 16 17:57:52 UTC 2021 aarch64 aarch64 aarch64 GNU/Linux

[carlossvg]

I confirm the same error happens with the ROS 2 Humble image