Total freeze of 2.4 kernel

This is not a detailed bug report, but it may nevertheless be interesting for others that have the same problem. I have the impression that my first report got lost somewhere, so this is the second attempt to post it.

We installed a 2.4.7 kernel on a Compaq Proliant server and it makes the machine freeze totally at various moments. We've been running 2.4 on several other non-server machines for a while without any problem at all, so we tried to figure out what may be causing the problem. Here is a list of what we know so far:

INITIAL SYMPTOMS

At totally unpredictable moments the sever hangs. Nothing on the display, no keyboard led response, no disk activity, no ping response on the net.

2.2.19 KERNEL

The machine ran a 2.2.19 kernel prior to the 2.4.7 kernel without any problems at all. Only kernel upgrades forced us to do reboots.

CPQHEALTH

There were Compaq cpqhealth modules in the kernel. Those are binary modules from Compaq that help to gather health information about the machine. The modules didn't load in a 2.4.7 kernel (cpqhealth 2.1 even created kernel stack dumps when loaded in a 2.4.7 kernel on another machine) so we removed the cpqhealth software. It didn't help.

CPQARRAY

This is the first machine with a Compaq SMART 3200 raid controller we tried with 2.4.7. I don't believe this is causing the problem, but it's worth mentioning I think.

MONITOR/MOUSE/KEYBOARD SWITCH

This also is the first machine with an electronic MONITOR/MOUSE/KEYBOARD SWITCH. Last weekend the machine ran w/o any problems at all, but today (monday) it had a hangup. We can be sure that nobody touched the switch during the weekend and today at was used most certainly, so there may be a relation between the switch and the hanging.

Of course we'll go on investigating this, but because the machine has a semi-production status we have to do this with care. However suggestions are wellcome.

Rolf

To gather more information, try adding the kernel debugger patch [1], booting with nmi watchdog [2] and a serial console [3].

[1] ftp://oss.sgi.com/projects/kdb/download/ix86
[2] For uni-processor, compile with CONFIG_X86_UP_IOAPIC=y, CONFIG_UP_NMI_WATCHDOG=y. For SMP, boot with option nmi_watchdog=2.
[3] Documentation/serial-console.txt