If you are using the HP health drivers for ProLiant servers (or at least the hp-wdt driver), any system hangs or panics caused by NMI’s (non-maskable interrupts) will be logged to the IML (Integrated Management Log) and can be viewed using iLO. The IML log is on the System Status page of the iLO web interface.

This is great, but the error messages logged are not very user friendly. NMI’s will be logged as Unrecoverable System Errors something like this:

An Unrecoverable System Error has occurred (Error code 0x0000002D, 0x00000000

The first 32-bit error code can be decoded using this table (which came from the man page for the hp-wdt driver):

00h (0x00000000) No source found
01h (0x00000001) Uncorrectable Memory Error
1Bh (0x0000001B) ASR NMI
20h (0x00000020) PCI Parity Error
27h (0x00000027) NMI Button Press
28h (0x00000028) SB_BUS_NMI
29h (0x00000029) ILO Doorbell NMI
2Ah (0x0000002A) ILO IOP NMI
2Bh (0x0000002B) ILO Watchdog NMI
2Ch (0x0000002C) Proc Throt NMI
2Dh (0x0000002D) Front Side Bus NMI
2Fh (0x0000002F) PCI Express Error
30h (0x00000030) DMA controller NMI
31h (0x00000031) Hypertransport/CSI Error

Hopefully, this will help you narrow down the real cause of the NMI.