rtfree? [a bit tedious]

Hello,

I hope someone can help shed some light on this!

Two (almost) identical Compaq DL380G2, 2x 1.4G PIII, 1G RAM, built-in 5i
array controller,  6 scsi disks as raid-5, dual psu's.

Neither of them could run SMP kernels since 6-CURRENT, however, a couple
of weeks ago one started to work flawlessly with a SMP kernel after a
fresh build septmeber 19th, no trace of instability. Yippiiee!

Yesterday I bravely rebuilt number two from fresh sources with a SMP 
kernel and then started portupgrade but as usual, the box froze dead 
after a few minutes into php5 and nothing helped apart from a hard reset.

It should be noted that during over a years time I haved circulated
various components between them to try to make sure it is not a hw fault
and I think it is not. The freezes *never* occurs with UP kernels. Also,
I have tested RH and Debian Linix SMP, all OK.

ACPI on/off does not matter.

The machine that freezes has "rtfree: 0xc43ef000 has 1 refs" messages
printed repeatedly on the console and syslog (address varies) and it 
displays "kernel: Limiting closed port RST response from 201 to 200 
packets/sec" during last part of boot.

"vmstat -i" shows no significant difference.

Some subtle details differ between them, the slightly newer one is the
problematic:

< CPU: Intel(R) Pentium(R) III CPU family      1400MHz (1390.66-MHz
686-class CPU)
<   Origin = "GenuineIntel"  Id = 0x6b1  Stepping = 1
---
> CPU: Intel(R) Pentium(R) III CPU - S         1400MHz (1396.44-MHz 
686-class CPU)
>   Origin = "GenuineIntel"  Id = 0x6b4  Stepping = 4

< ciss0: <Compaq Smart Array 5i> port 0x2000-0x20ff mem
0xf5dc0000-0xf5dfffff,0xf3ef0000-0xf3ef3fff irq 16 at device 1.0 on pci0
---
> ciss0: <Compaq Smart Array 5i> port 0x2000-0x20ff mem 
0xf5ec0000-0xf5efffff,0xf3ef0000-0xf3ef3fff irq 16 at device 1.0 on pci0

< fxp0: <Intel 82559 Pro/100 Ethernet> port 0x2400-0x243f mem
0xf5db0000-0xf5db0fff,0xf5c00000-0xf5cfffff irq 18 at device 2.0 on pci0
---
> fxp0: <Intel 82559 Pro/100 Ethernet> port 0x2400-0x243f mem 
0xf5eb0000-0xf5eb0fff,0xf5d00000-0xf5dfffff irq 18 at device 2.0 on pci0