system locks up while attempting to hibernate

[David Monro]

Description: Ubuntu 10.04.1 LTS
Release: 10.04

$ apt-cache policy linux-image-generic
linux-image-generic:
  Installed: 2.6.32.24.25
  Candidate: 2.6.32.24.25
  Version table:
 *** 2.6.32.24.25 0
        500 http://apt-proxy/ubuntu/ lucid-updates/main Packages
        500 http://apt-proxy/ubuntu-security/ lucid-security/main Packages
        100 /var/lib/dpkg/status
     2.6.32.21.22 0
        500 http://caponier/isomount/ubuntu-10.04-dvd-amd64/ lucid/main Packages
        500 http://apt-proxy/ubuntu/ lucid/main Packages

Kernel is 2.6.32-24-generic

Machine should write data to disk and power off.

Instead, machine locks up with a blank screen.

By attaching a serial console, booting with the options "verbose debug console=ttyS0,115200n8 no_console_suspend", and doing

echo '8 4 1 7' > /proc/sys/kernel/printk

before attempting to hibernate, I can see that it gets as far as

[ 115.674186] PM: freeze of drv:sd dev:2:0:0:0 complete after 387.856 msecs

where it hangs for a minute, and then spits out
[ 180.389988] BUG: soft lockup - CPU#0 stuck for 61s! [pm-hibernate:2635]
and a stack trace.
Which then repeats every minute or so until I hit the reset button.