Comment 5 for bug 398392

Ok, I think I found the problem.

In the BIOS settings, neither ACPI nor ACPI APIC were enabled.
Enabling ACPI caused the system not to boot, due to bug 11941 I think, so I let it disabled.
I enabled the flag ACPI APIC and did some stress tests... now the system doesn't hang anymore.

The file /proc/interrupts now reads as follows:

           CPU0
  0: 185 IO-APIC-edge timer
  1: 1334 IO-APIC-edge i8042
  8: 0 IO-APIC-edge rtc0
  9: 0 IO-APIC-fasteoi acpi
 12: 36697 IO-APIC-edge i8042
 14: 50498 IO-APIC-edge pata_via
 15: 20757 IO-APIC-edge pata_via
 16: 451867 IO-APIC-fasteoi sata_via, mga@pci:0000:01:00.0
 17: 0 IO-APIC-fasteoi uhci_hcd:usb3
 18: 457336 IO-APIC-fasteoi sata_via, uhci_hcd:usb4
 19: 587316 IO-APIC-fasteoi sata_via, ehci_hcd:usb1
 20: 0 IO-APIC-fasteoi sata_via
 21: 5658 IO-APIC-fasteoi ehci_hcd:usb2, uhci_hcd:usb5, uhci_hcd:usb6, uhci_hcd:usb7, uhci_hcd:usb8
 22: 2240 IO-APIC-fasteoi VIA8237
 23: 2688052 IO-APIC-fasteoi eth0
NMI: 0 Non-maskable interrupts
LOC: 288082 Local timer interrupts
RES: 0 Rescheduling interrupts
CAL: 0 Function call interrupts
TLB: 0 TLB shootdowns
SPU: 0 Spurious interrupts
ERR: 0
MIS: 0

Quite different from the previous one :-)

So in the end the problem seems to be caused by not having enabled the IO-APIC in the BIOS settings.