View Single Post
Old 12-25-2018, 12:51 AM   #16
knc1
Going Viral
knc1 ought to be getting tired of karma fortunes by now.knc1 ought to be getting tired of karma fortunes by now.knc1 ought to be getting tired of karma fortunes by now.knc1 ought to be getting tired of karma fortunes by now.knc1 ought to be getting tired of karma fortunes by now.knc1 ought to be getting tired of karma fortunes by now.knc1 ought to be getting tired of karma fortunes by now.knc1 ought to be getting tired of karma fortunes by now.knc1 ought to be getting tired of karma fortunes by now.knc1 ought to be getting tired of karma fortunes by now.knc1 ought to be getting tired of karma fortunes by now.
 
knc1's Avatar
 
Posts: 17,212
Karma: 18210809
Join Date: Feb 2012
Location: Central Texas
Device: No K1, PW2, KV, KOA
Quote:
Originally Posted by NiLuJe View Post
@makue: I'd first take a look at a *full* log dumped via showlog and not ;dm, because Amazon's logging facilities sometime do funny things when coalescing logs...

(i.e., here, I'm only seeing the replay of dmesg's backlog done once the system logger boots up, which doesn't tell us much about when exactly it hung, besides "before syslog-ng appeared to have been brought up").
Could we automate that?


Consider; the first (the only) program the kernel runs after it finishes start-up is "init".
Perhaps jam a "dmesg" and/or "showlog" call very early into the list of things "init" starts?


If such a modification never gets called, then we know the system crashed before reaching "init".


The root fs is mounted when "init" is started ...
But if we are having file system errors, then writing our extra log output could be a "bad idea" ...
But if we set-up a ram disk to write (or re-direct) our special logging too...
Also, if required, we could net-cat it off of the machine somewhat later.




Whatever, it is going to be hard to debug.
(Note: I think debugfs is mounted, but I am not sure when in the process it gets mounted. Early, with /proc and /sys ??)
knc1 is offline   Reply With Quote