[Bug 31531] System freezes when moving mouse under heavy I/O load

[TragicWarrior]

Public bug reported:
https://launchpad.net/malone/bugs/31531

Affects: linux-source-2.6.12 linux-image-2.6.12-10-686-smp (Ubuntu)
       Severity: Normal
       Priority: (none set)
         Status: Unconfirmed

Description:
When I/O traffic is very heavy on the system, moving the mouse
eventually causes the system to hang.  The system is completely frozen
(num lock, caps lock dead) and must be rebooted (power cycle).  I have
reproduced this many times using the following steps:

1.  Open gnome-terminal
2.  Put a disc in the cd-rom drive
3.  dd if=/dev/cdrom of=myimage.iso bs=2048k (or 1024k or 4096k)
4.  move mouse around

I am running linux-image-2.6.12-10-686-smp on dual-P4 system with a
dac960 raid controller.  The I/O scheduler is elevator=deadline.