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recent bookmarks from jmPeek and poke in the age of Linux2013-03-06T22:32:52+00:00
http://blog.viraptor.info/post/44424140237/peek-and-poke-in-the-age-of-linux
jmSome time ago I ran into a production issue where the init process (upstart) stopped behaving properly. Specifically, instead of spawning new processes, it deadlocked in a transitional state. [...] What’s worse, upstart doesn’t allow forcing a state transition and trying to manually create and send DBus events didn’t help either. That meant the sane options we were left with were:
restart the host (not desirable at all in that scenario);
start the process manually and hope auto-respawn will not be needed.
Of course there are also some insane options. Why not cheat like in the old times and just PEEK and POKE the process in the right places? The solution used at the time involved a very ugly script driving gdb which probably summoned satan in some edge cases. But edge cases were not hit and majority of hosts recovered without issues.
]]>debugging memory linux upstart peek poke ptrace gdb processes hackshttps://pinboard.in/https://pinboard.in/u:jm/b:1b09b0dbaa28/