Machine Check Exception in 2.6.0-test2

Hi all,

When running a fairly CPU and thread-hungry application under 2.5.75, 2.6.0-test1 and 2.6.0-test2 I'm getting the following error messages on the console:

Jul 25 00:16:31 durak kernel: CPU 0: Machine Check Exception: 0000000000000004
Jul 25 00:16:31 durak kernel: Bank 0: b600000000000175 at 0000000025a0cff8
Jul 25 00:16:31 durak kernel: Kernel panic: CPU context corrupt

Once I get this message, one of the threads becomes unkillable yet remains soaking up CPU cycles.

This does not happen in the 2.4 kernels. How do I go about finding the source of the problem? The address indicated in the second line indicates that this happened somewhere in userspace (0x25a0cff8), but since this is a commercial package I don't have any symbolic info. This last address changes between runs, so I assume it's a virtual address.

Any ideas welcome.

Best regards,

Ben