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Why can't root send a fatal signal to PID 1/init process (sudo kill -9 1)?

As stated here.

marked as duplicate by peterph, slm, jasonwryan, jordanm, Joseph R. Oct 16 '13 at 22:24

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  • Because it is a dangerous way to reboot the system. – Doug O'Neal Oct 16 '13 at 18:20
  • couldn't the kernel spawn another, as soon as it detects the absence of one? – Bleeding Fingers Oct 16 '13 at 18:25
  • @hus787 It could, but the only process the kernel spawns is init (or nowadays, an init replacement). init takes care of spawning processes. There isn't really a reason to kill init. – kurtm Oct 16 '13 at 19:08
  • 1
    @kurtm there is one: suppose you log into your remote system and realize you have an attacker there. Before you manage to do anything else, he realizes you know of his presence and issues rm -Rf /. In that case kernel panic is the best way to save as much data as possible - kill -9 1 is (or would be) the only fast way to trigger one remotely. I actually believe it was possible on Linux years ago. (/me is not in the mood of looking that up now.) – peterph Oct 16 '13 at 19:12
  • Interesting reading about implementation on Linux: flossstuff.wordpress.com/2013/08/16/why-you-cant-kill-init – peterph Oct 16 '13 at 19:16

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