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Kernel livepatching, beer, squash
Daylight savings time defeats Vorsprung durch Technik
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Linux is now a CNA: http://www.kroah.com/log/blog/2024/02/13/linux-is-a-cna/

This has taken a long time, I'd like to thank all the groups that helped, and especially the CVE group themselves. Our application was a bit different than other groups, but they understood that this is important for security overall.
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Snow play
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Basil pesto makes for a pretty good compression algorithm.
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Edited 11 months ago
Squash, Coding, & Robotics Camp?! I wonder if I could have claimed a continuing education expense with the employer 😁

https://www.hisawyer.com/marketplace/activity-set/474691
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Do we still say WYSIWYG, or am I just paranoid I'll date myself using it around the kids?
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Arrays in bash are the same "turn around now" warning that objects were in Perl.
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From my first programming book, Learning Commodore 64 BASIC. More like 34 years later and I still have fun throwing my (or Kilroy's) name up on the screen.

https://archive.org/details/LearningCommodore64Basic
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Hmm, GitLab offers some interesting emoji suggestions to spice up a merge request. Can it sort by controversial 🔥 ?
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TIL: gcc’s -H flag to untangle header files

While backporting upstream patches to an older distro kernel:

  f6ac18fafcf6 sched: Improve try_invoke_on_locked_down_task()
  9b3c4ab3045e sched,rcu: Rework try_invoke_on_locked_down_task()
  00619f7c650e sched,livepatch: Use task_call_func()
  8850cb663b5c sched: Simplify wake_up_*idle*()
  5de62ea84abd sched,livepatch: Use wake_up_if_idle()

I ran into compilation error:

  kernel/livepatch/transition.c:434:33: error: implicit declaration of function ‘wake_up_if_idle’

A closer look at the upstream commits shows (“sched,livepatch: Use task_call_func()”) removed “../sched/sched.h” from kernel/livepatch/transition.c. wake_up_if_idle() is defined in include/linux/sched/idle.h so there is probably a connection – but how does this even build upstream and how to untangle the rat’s nest of kernel includes?

Enter gcc and the -H flag.

I rebuilt the upstream kernel kernel/livepatch/transition.o with V=1 and snarfed its gcc compilation line. Pasted into the terminal, added -H, and gcc generates a long header file stack. The header of interest was six includes deep:

  . ./include/linux/cpu.h
  .. ./include/linux/node.h
  ... ./include/linux/device.h
  .... ./include/linux/energy_model.h
  ..... ./include/linux/sched/topology.h
  ...... ./include/linux/sched/idle.h

Moving back to my distro kernel, its device.h did not include energy_model.h (introduced upstream by 1bc138c62295 (“PM / EM: add support for other devices than CPUs in Energy Model”).

Mystery solved and a new trick to remember for a future problem.

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A brisk disc session between meetings.
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Had to verify. And yes. Kernighan and Ritchie really did this. TIL :)

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Obligatory #introduction: linux kernel livepatch for Red Hat kpatch by day, squash player and Philly sports fan by night. Reverb > distortion, pilsner > IPA, and other opinions.
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