I'm seeing the exact same behavior as Claudio.  I did a bunch of investigation and here is what I found:

For the last week or so, almost every morning when I come into work my system is hung up in a strange way.  I can move my mouse but I never get asked for my password to unlock my screen.  I can C-A-F1 etc. to get back to a console but after I type my username at the login prompt, I never get asked for a password and then that console is locked up.  If I have a console session already logged in from the day before, then I can use it for a while but eventually some command will lock hard; can't ^C, can't ^Z, can't kill -9, nothing.

If I try to C-A-D to reboot the system starts to come down but then hangs, hard, trying to bring down automount.  Reset just tries to reboot again and hangs in the same place.  I have to power off/on the system completely.  Bummer.

So, I tried debugging this problem.  First, I logged in as root on every console (F1-F6).  The next morning when the system was hung, I found a command that hung (just "ls") and then I ran it in another console under strace.

It turns out what's happening is it's opening /proc/mounts, which succeeds, then trying to read(2).  The read system call never returns and there's no way to kill that process, at all, once it's in that state.  Also I note the load on the system is very high: typically over 7.  However top shows no processes chewing CPU.  I also note that there are some "duplicate" automount processes running (that is, more than one for the same map).  After I reboot, of course, everything is fine.

Last night I started all the consoles and in one of them I wrote a little shell script that ran `date`, then did cat /proc/mounts, then slept for 15 seconds, then did it again.  I piped the output to a file.

I found that the hang happened last night at 22:51 EDT.  There was nothing interesting in the messages log, but in syslog I find a lot of messages right around that time trying to do this silly .Trash stuff:

Jun  2 22:36:02 psmithub -- MARK --
Jun  2 22:50:57 psmithub automount[29205]: failed to mount /opt/net/.Trash
Jun  2 22:50:57 psmithub automount[29206]: failed to mount /opt/net/.Trash-10490
Jun  2 22:50:57 psmithub automount[29207]: failed to mount /export/autofs/.Trash
Jun  2 22:50:57 psmithub automount[29208]: failed to mount /export/autofs/.Trash-10490
Jun  2 22:51:00 psmithub automount[29217]: failed to mount /nfs/.Trash
Jun  2 22:51:00 psmithub automount[29218]: failed to mount /nfs/.Trash-10490
Jun  2 22:51:00 psmithub automount[29219]: failed to mount /mnt/.Trash
Jun  2 22:51:00 psmithub automount[29220]: failed to mount /mnt/.Trash-10490
Jun  2 22:51:00 psmithub automount[29221]: >> /sbin/showmount: can't get address for .Trash
Jun  2 22:51:00 psmithub automount[29221]: lookup(program): lookup for .Trash failed
Jun  2 22:51:00 psmithub automount[29221]: failed to mount /net/.Trash
Jun  2 22:51:00 psmithub automount[29228]: >> /sbin/showmount: can't get address for .Trash-10490
Jun  2 22:51:00 psmithub automount[29228]: lookup(program): lookup for .Trash-10490 failed
Jun  2 22:51:00 psmithub automount[29228]: failed to mount /net/.Trash-10490
Jun  2 22:51:00 psmithub automount[29237]: failed to mount /opt/net/.Trash
Jun  2 22:51:00 psmithub automount[29238]: failed to mount /opt/net/.Trash-10490
Jun  2 22:51:00 psmithub automount[29239]: failed to mount /export/autofs/.Trash
Jun  2 22:51:00 psmithub automount[29240]: failed to mount /export/autofs/.Trash-10490
Jun  2 22:51:03 psmithub automount[29250]: failed to mount /nfs/.Trash
Jun  2 22:51:03 psmithub automount[29251]: failed to mount /nfs/.Trash-10490
Jun  2 22:51:03 psmithub automount[29252]: failed to mount /mnt/.Trash
Jun  2 22:51:03 psmithub automount[29253]: failed to mount /mnt/.Trash-10490
Jun  2 22:51:03 psmithub automount[29254]: >> /sbin/showmount: can't get address for .Trash
Jun  2 22:51:03 psmithub automount[29254]: lookup(program): lookup for .Trash failed
Jun  2 22:51:03 psmithub automount[29254]: failed to mount /net/.Trash
Jun  2 22:51:03 psmithub automount[29261]: >> /sbin/showmount: can't get address for .Trash-10490
Jun  2 22:51:03 psmithub automount[29261]: lookup(program): lookup for .Trash-10490 failed
Jun  2 22:51:03 psmithub automount[29261]: failed to mount /net/.Trash-10490
Jun  2 22:51:03 psmithub automount[29270]: failed to mount /opt/net/.Trash
Jun  2 22:51:03 psmithub automount[29271]: failed to mount /opt/net/.Trash-10490
Jun  2 22:51:03 psmithub automount[29272]: failed to mount /export/autofs/.Trash
Jun  2 22:51:03 psmithub automount[29273]: failed to mount /export/autofs/.Trash-10490
Jun  2 22:51:03 psmithub automount[29274]: failed to mount /nfs/.Trash
Jun  2 22:51:03 psmithub automount[29275]: failed to mount /nfs/.Trash-10490
Jun  2 22:51:03 psmithub automount[29276]: failed to mount /mnt/.Trash
Jun  2 22:51:03 psmithub automount[29277]: failed to mount /mnt/.Trash-10490
Jun  2 22:51:03 psmithub automount[29278]: >> /sbin/showmount: can't get address for .Trash
Jun  2 22:51:03 psmithub automount[29278]: lookup(program): lookup for .Trash failed
Jun  2 22:51:03 psmithub automount[29278]: failed to mount /net/.Trash
Jun  2 22:51:03 psmithub automount[29285]: >> /sbin/showmount: can't get address for .Trash-10490
Jun  2 22:51:03 psmithub automount[29285]: lookup(program): lookup for .Trash-10490 failed
Jun  2 22:51:03 psmithub automount[29285]: failed to mount /net/.Trash-10490
Jun  2 22:51:03 psmithub automount[29294]: failed to mount /opt/net/.Trash
Jun  2 22:51:03 psmithub automount[29295]: failed to mount /opt/net/.Trash-10490
Jun  2 22:51:03 psmithub automount[29296]: failed to mount /export/autofs/.Trash
Jun  2 22:51:03 psmithub automount[29297]: failed to mount /export/autofs/.Trash-10490
Jun  2 22:51:03 psmithub automount[29298]: failed to mount /nfs/.Trash
Jun  2 22:51:03 psmithub automount[29299]: failed to mount /nfs/.Trash-10490
Jun  2 22:51:03 psmithub automount[29300]: failed to mount /mnt/.Trash
Jun  2 22:51:03 psmithub automount[29301]: failed to mount /mnt/.Trash-10490
Jun  2 22:51:03 psmithub automount[29302]: >> /sbin/showmount: can't get address for .Trash
Jun  2 22:51:03 psmithub automount[29302]: lookup(program): lookup for .Trash failed
Jun  2 22:51:03 psmithub automount[29302]: failed to mount /net/.Trash
Jun  2 22:51:03 psmithub automount[29309]: >> /sbin/showmount: can't get address for .Trash-10490
Jun  2 22:51:03 psmithub automount[29309]: lookup(program): lookup for .Trash-10490 failed
Jun  2 22:51:03 psmithub automount[29309]: failed to mount /net/.Trash-10490
Jun  2 22:51:08 psmithub automount[29209]: >> mount.nfs: access denied by server while mounting snap-dev01:/user/.Trash
Jun  2 22:51:08 psmithub automount[29209]: mount(nfs): nfs: mount failure snap-dev01:/user/.Trash on /user/.Trash
Jun  2 22:51:08 psmithub automount[29209]: failed to mount /user/.Trash
Jun  2 22:51:08 psmithub automount[29318]: failed to mount /nfs/.Trash
Jun  2 22:51:08 psmithub automount[29319]: failed to mount /nfs/.Trash-10490
Jun  2 22:51:08 psmithub automount[29320]: failed to mount /mnt/.Trash
Jun  2 22:51:08 psmithub automount[29321]: failed to mount /mnt/.Trash-10490
Jun  2 22:51:08 psmithub automount[29322]: >> /sbin/showmount: can't get address for .Trash
Jun  2 22:51:08 psmithub automount[29322]: lookup(program): lookup for .Trash failed
Jun  2 22:51:08 psmithub automount[29322]: failed to mount /net/.Trash
Jun  2 22:51:08 psmithub automount[29329]: >> /sbin/showmount: can't get address for .Trash-10490
Jun  2 22:51:08 psmithub automount[29329]: lookup(program): lookup for .Trash-10490 failed
Jun  2 22:51:08 psmithub automount[29329]: failed to mount /net/.Trash-10490
Jun  2 22:51:29 psmithub automount[29241]: >> mount.nfs: access denied by server while mounting snap-dev01:/user/.Trash-10490
Jun  2 22:51:29 psmithub automount[29241]: mount(nfs): nfs: mount failure snap-dev01:/user/.Trash-10490 on /user/.Trash-10490
Jun  2 22:51:29 psmithub automount[29241]: failed to mount /user/.Trash-10490
Jun  2 22:51:29 psmithub automount[29342]: failed to mount /nfs/.Trash
Jun  2 22:51:29 psmithub automount[29343]: failed to mount /nfs/.Trash-10490
Jun  2 22:51:29 psmithub automount[29344]: failed to mount /mnt/.Trash
Jun  2 22:51:29 psmithub automount[29345]: failed to mount /mnt/.Trash-10490
Jun  2 22:51:29 psmithub automount[29346]: >> /sbin/showmount: can't get address for .Trash
Jun  2 22:51:29 psmithub automount[29346]: lookup(program): lookup for .Trash failed
Jun  2 22:51:29 psmithub automount[29346]: failed to mount /net/.Trash
Jun  2 22:51:29 psmithub automount[29353]: >> /sbin/showmount: can't get address for .Trash-10490
Jun  2 22:51:29 psmithub automount[29353]: lookup(program): lookup for .Trash-10490 failed
Jun  2 22:51:29 psmithub automount[29353]: failed to mount /net/.Trash-10490
Jun  2 22:51:34 psmithub automount[29212]: mount(nfs): nfs: mount failure snap-dev01:/tools on /opt/net/tools
Jun  2 22:51:34 psmithub automount[29212]: failed to mount /opt/net/tools

The output of my shell script looks like this:

...
Mon Jun  2 22:51:30 EDT 2008
rootfs / rootfs rw 0 0
none /sys sysfs rw,nosuid,nodev,noexec 0 0
none /proc proc rw,nosuid,nodev,noexec 0 0
udev /dev tmpfs rw,relatime 0 0
fusectl /sys/fs/fuse/connections fusectl rw,relatime 0 0
/dev/disk/by-uuid/c7ada654-6e09-4400-ae85-c93e7fcd99d7 / ext3 rw,relatime,errors=remount-ro,data=ordered 0 0
/dev/disk/by-uuid/c7ada654-6e09-4400-ae85-c93e7fcd99d7 /dev/.static/dev ext3 rw,relatime,errors=remount-ro,data=ordered 0 0
tmpfs /var/run tmpfs rw,nosuid,nodev,noexec 0 0
tmpfs /var/lock tmpfs rw,nosuid,nodev,noexec 0 0
tmpfs /lib/modules/2.6.24-17-generic/volatile tmpfs rw,relatime 0 0
tmpfs /dev/shm tmpfs rw,relatime 0 0
devpts /dev/pts devpts rw,relatime 0 0
tmpfs /var/run tmpfs rw,nosuid,nodev,noexec 0 0
tmpfs /var/lock tmpfs rw,nosuid,nodev,noexec 0 0
/dev/sda5 /home ext3 rw,relatime,data=ordered 0 0
securityfs /sys/kernel/security securityfs rw,relatime 0 0
rpc_pipefs /var/lib/nfs/rpc_pipefs rpc_pipefs rw,relatime 0 0
automount(pid5466) /net autofs rw,relatime,fd=4,pgrp=5466,timeout=300,minproto=2,maxproto=4,indirect 0 0
automount(pid5367) /mnt autofs rw,relatime,fd=4,pgrp=5367,timeout=60,minproto=2,maxproto=4,indirect 0 0
automount(pid5404) /nfs autofs rw,relatime,fd=4,pgrp=5404,timeout=3600,minproto=2,maxproto=4,indirect 0 0
automount(pid5532) /user autofs rw,relatime,fd=4,pgrp=5532,timeout=300,minproto=2,maxproto=4,indirect 0 0
automount(pid5612) /export/autofs autofs rw,relatime,fd=4,pgrp=5612,timeout=60,minproto=2,maxproto=4,indirect 0 0
automount(pid5684) /opt/net autofs rw,relatime,fd=4,pgrp=5684,timeout=36000,minproto=2,maxproto=4,indirect 0 0
nfsd /proc/fs/nfsd nfsd rw,relatime 0 0

Mon Jun  2 22:51:45 EDT 2008

then it just stops dead.


Is anyone listening or paying any attention to this bug!?!?!  I can't take rebooting my system every morning.