hard lockups

Has anyone been experiencing non-panic hard freezes lately? I just started running -current a couple of weeks ago, before that I had 5.0-RELEASE without seeing any problems.

Occasionally, I will just have a machine lockup, no panics, nothing. The machine is unresponsive to the network also.

Usually, there is some sort of disk activity - I have seen the lockup 3 or 4 times trying to compile/install things, and 2x today, once compiling a new kernel, the other while redirecting output from a job to a text file.

Today's lockups were using a May 6 kernel, SMP, none of the debugging options, SCHED_ULE, LAZY_SWITCH, ADAPTIVE_MUTEXES, and ZERO_COPY_SOCKETS. I have since recompiled to include all the debugging options, but the only thing that has shown up is a lock order reversal in the sound code.

This machine is a dual celeron and uses ata drives. DMA is turned on. Ethernet is via a 3c905B controller. The one hard drive is using the onboard HPT366 controller, not the PIIX one.

I'm not sure what else to include. I am always suspicious of hard lockups, it is difficult to pinpoint what causes them since there is no log entry to read. It could easily be a hardware issue, but since I hadn't had problems before -current I thought I would write in.

-Will