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Re: ulogd unaligned trap



On Sat, Jan 21, 2006 at 07:25:47PM -0500, Jim Crilly wrote:
> On 01/21/06 09:45:15PM +0000, Carlos Rodrigues wrote:
> > Hi!
> > 
> > I have a couple of Alpha machines (XP1000 and ES40) which spit this
> > message regularly to /var/log/messages and the console:
> > 
> > Jan 21 21:41:05 ulisses kernel: ulogd(26459): unaligned trap at
> > 00000200001e2ce8: 000002000020a0e5 28 4
> > Jan 21 21:41:05 ulisses kernel: ulogd(26459): unaligned trap at
> > 00000200001e2d64: 000002000020a0e9 28 4
> > Jan 21 21:41:05 ulisses kernel: ulogd(26459): unaligned trap at
> > 00000200001e2da8: 000002000020a0e1 28 3
> > Jan 21 21:41:05 ulisses kernel: ulogd(26459): unaligned trap at
> > 00000200001e2df4: 000002000020a0e1 28 2
> > 
> > I think (not sure) this started happening since the latest kernel
> > security update.
> > 
> > Both machines are running sarge, with the stock (debian) 2.4.27 kernel
> > (smp, in the ES40).
> > 
> > I don't think this is affecting the operation of ulogd, but I'm not
> > sure. Anyways, I reported this to the BTS.
> > 
> > Any ideas?
> > 
> 
> Ulogd will keep running just fine. What's happening is it's attempting
> to access memory that's not aligned properly, the hardware complains
> and the kernel fixes the access so the hardware is happy. It cause
> a bit of a slowdown since the kernel has to fix up the operation,
> but it doesn't cause any other problems.

It can be more than a little slowdown, if it happens a lot.

Check for the frequency via:

	cat /proc/cpuinfo | grep unalign

and see how often/how much it changes.

BTW, the addresses spit out in the message look like they are from
a module, which may make tracking it down a bit more difficult...

Good luck.

 --Jay++

---------------------------------------------------------------
Jay A Estabrook                            HPTC - XC I & B
Hewlett-Packard Company - ZKO1-3/D-B.8     (603) 884-0301
110 Spit Brook Road, Nashua NH 03062       Jay.Estabrook@hp.com
---------------------------------------------------------------



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