Linux Archive

Linux Archive (http://www.linux-archive.org/)
-   Debian User (http://www.linux-archive.org/debian-user/)
-   -   Surprising boot problem with modprobe and a stray named pipe (http://www.linux-archive.org/debian-user/227917-surprising-boot-problem-modprobe-stray-named-pipe.html)

Scott Gifford 01-14-2009 09:07 PM

Surprising boot problem with modprobe and a stray named pipe
 
I had an interesting problem today. A friend called me up to say that
after an update, his Etch box wouldn't boot amymore, and could I come
by and take a look at it.

It was hanging waiting for udev to settle, and udev was starting tons
of modprobe processes that were just hanging.

Indeed, booting with "init=/bin/sh" I couldn't modprobe anything. Of
course my first guess was that the kernel was corrupt, modules were
corrupt, there was a version mismatch, etc.

Eventually I tried strace'ing modprobe. It was hanging trying to read
from a named pipe, /etc/modprobe.d/supervise/control. Looks like some
kind of coordination system, used to let modprobe wait for something
to finish. But my other Etch machines didn't have it, and eventually
it dawned on me: that directory is supposed to be somewhere else. It
looks like something (possibly minor filesystem corruption) caused a
daemontools supervise directory to end up in /etc/modprobe.d, and when
modprobe tried to read its configuration by scanning everything in
that directory, it got stuck trying to read from the named pipe.

It was a pretty bizarre failure, and the symptoms weren't obvious at
all. Probably if I hadn't noticed that, we would have ended up doing
an OS reinstall.

Just thought I'd share a sysadmin war story,

----Scott.


--
To UNSUBSCRIBE, email to debian-user-REQUEST@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org

"Boyd Stephen Smith Jr." 01-14-2009 10:16 PM

Surprising boot problem with modprobe and a stray named pipe
 
On Wednesday 2009 January 14 16:07:37 Scott Gifford wrote:
>But my other Etch machines didn't have it, and eventually
>it dawned on me: that directory is supposed to be somewhere else. It
>looks like something (possibly minor filesystem corruption)

It's just like I say everytime a box I administer fails to boot:
"Fsck it all!"

--
Boyd Stephen Smith Jr. ,= ,-_-. =.
bss@iguanasuicide.net ((_/)o o(\_))
ICQ: 514984 YM/AIM: DaTwinkDaddy `-'(. .)`-'
http://iguanasuicide.net/ \_/


All times are GMT. The time now is 05:02 PM.

VBulletin, Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO ©2007, Crawlability, Inc.