Lockups with loop'ed sparse files on reiserfs?

From: Christian Jaeger (christian.jaeger@ethlife.ethz.ch)
Date: Fri Jun 13 2003 - 08:38:44 EST


I've experienced 3 lockups in the last few days, all while using
sparse files. Could also be problems with UML, SKAS, raid5 over loop
device, or loop devices with vfat files, but it looks like the only
common thing is sparse files on reiserfs.

1.) kernel 2.4.20 from debian unstable (= kernel.org kernel with
quite a few security and other patches), additionally patched with
kernel-patch-skas 3-1 from debian. Started user-mode-linux using a
sparse file with an ext2 filesystem on it, using tap0 networking, did
apt-get upgrade inside this uml (which started to download (and
already unpack?) quite a bit of stuff), halfway through the whole
(host) system froze. Still responded to pings, but telnet $host 80
would not show any activity from running apache. Went to the server
room, I could change virtual terminals with Alt-<number>, but could
not log in. Reset.

2.) same kernel:
- created 6 sparse files of 650MB each, on reiserfs filesystems (some
of them on the same filesystem), and 2 files of 650MB on a vfat
- Tied them to /dev/loop*,
- mdadm /dev/md0 -C -l 5 -n 7 -x 1 /dev/loop*
- then (while the array was building) mkreiser /dev/md0,
- mount /dev/md0 /mnt/md0
- cd /mnt/md0; netcat -l -p "$port" | multifeed '|' sh -c 'exec
md5sum >&2' '&' cat | gpg | lzop -d | tar xf -
   (where multifeed is a C program by myself feeding the data to
multiple processes)
   basically fetch data from tcp and untar it onto the filesystem.
After about 500MB of data has been written onto /mnt/md0, the box
froze. Still responded to ping, but not to telnet $host 80. Could
switch vt's, type root and enter password, but didn't get a login.

3.) kernel 2.4.18 from kernel.org (the machine ran without any
problem (except for sporadically switching off dma on /dev/hda) with
this kernel for about a year):
Did same thing as mentioned under 2.) (rm -rf /mnt/md0/* before
starting the write again). This time it happened already after
filling the md partition with about 200MB. And this time, while still
responding to pings and being able to switch vt's, it wouldn't react
to hitting the keys 'root'.

I'd mainly like to know if all of what I did is supported or not.

The machine is a AMD Duron 1Ghz with 256MB RAM, 3 IDE harddisks (but
only hda and hdd involved in the above), 2 ethernet cards using

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This archive was generated by hypermail 2b29 : Sun Jun 15 2003 - 22:00:36 EST