Re: [Patch] UML: spurious interrupt freezes guest

From: Shane Hathaway
Date: Tue Jan 20 2009 - 00:32:54 EST


Jeff Dike wrote:
> On Mon, Jan 19, 2009 at 08:53:25PM -0700, Shane Hathaway wrote:
>> A new instance of user mode linux that I created over the past couple of
>> days worked pretty well except that it had a habit of freezing after a
>> few minutes. Every time it froze, the last message on the console was
>> either:
>>
>> spurious interrupt in ubd_handler, err = 4
>
> What version and what's the workload?

I got the spurious interrupt with both Linux 2.6.28.1 and 2.6.27.12 as
guests. The host runs 2.6.9-42.0.3.ELsmp.

I am putting OpenVPN and Asterisk inside the guest. The guest is based
on Ubuntu 8.10. The spurious interrupt happened more often when I
restricted the guest's RAM. The processes in the guest normally consume
a total of about 20-24 MB of RAM. I limited the guest's RAM to 48 MB
and gave it a 64 MB swap partition. When I gave the guest only 32 MB,
the spurious interrupt seemed to happen more often.

The best way I found to trigger the spurious interrupt was to try to
"apt-get install" many packages at once. The download would succeed,
but the guest would freeze partway through the install.

Shane
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