[CentOS] is udev necessary?

Berend Dekens berend at cyberwizzard.nl
Mon Nov 17 04:23:12 UTC 2008

Rudi Ahlers schreef:
> Unfortunately I don't see anything useful in the logs. If I let it
> bootup by itself, then it reboots just after booting udev. If,
> however, I press CTRL+C the moment I see udev on the screen, I have
> attached a snippet from /var/log/message - which doesn't show me
> anything at all.
Indeed - I see some error messages about memory being assign to weird 
places and ata1 claiming to be a dummy... But nothing that should 
warrant something like a reboot...

I did however see some Xen messages. I am no expert so I can't see if 
this is a hypervisor kernel or a virtual machine kernel. If you are not 
planning on using the machine for or in an Xen environment, you could 
try to switch to a regular one (even if it is for testing). I have had 
some strange behaviour from systems which reacted poorly to 
virtualisation software (most of those get fixed but they can send you 
into the wrong direction).

Another thing that came to mind was that udev might finish properly but 
the next task might crash the system. I would however expect something 
in the message output. Did you check if the udev service claimed to be 
started if you ctrl+c out of it? Its unlikely but can't hurt to test.

If all else fails, you could probably disable udev for now and check if 
everything is working (make sure you don't need pluggable device 
support, otherwise you really do need udev). Plan B would be to Google 
for a debugging mode in udev - unless someone on the list knows how to 
activate that. My guess would be to edit the udev script and pass 
something to the program (most of the time its something like '-v' or 
'-vv' or '-d' or something - look for verbose or debug options).

Good luck,

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