This locks my IBM x3550 : "do_IRQ: 0.177 No irq handler for vector" I need a power cycle after that. Messages file reveals.. Not much really : Jan 30 20:32:10 localhost kernel: Bluetooth: HIDP (Human Interface Emulation) ver 1.1 Jan 30 20:32:10 localhost kernel: SELinux: initialized (dev autofs, type autofs), uses genfs_contexts Jan 30 20:32:10 localhost last message repeated 2 times Jan 30 20:32:10 localhost kernel: do_IRQ: 0.177 No irq handler for vector Looking around I find Mr Andrew Morton on the case, which is a relief. http://lkml.org/lkml/2007/1/22/121 It's being seen on 16-core systems, I'm running only a four core box though. Doesn't look like a patch is out yet so my original plan of trying Rawhide probably will not help. I have not (yet?) had the problem on 2.6.18-1.2798.fc6. It only seems to be in the 2.6.19 kernel.