Re: Kernel traces coming back with trash/clutter [SOLVED]

From: Mark Hull-Richter
Date: Wed Apr 25 2007 - 15:14:55 EST


On 4/24/07, John Anthony Kazos Jr. <jakj@xxxxxxxxxxx> wrote:
> > Perhaps you have something looping that's outputting KERN_DEBUG with a
> > null message? Or one of your diagnostic printk statements includes
> > KERN_DEBUG with no actual message?
> >
> No, they are all KERN_DEBUG<space>"some string here", almost all with
> some formatted output as well. Could I be overloading the printk
> output buffer, as in possibly too tightly repeated/looped code to be
> able to output it all?

It is possible, I suppose. Is what you're working on open-source? If so,
you could send it to me and I could try and reproduce it here and track it
down. If you want me to, that is. (If you do send, please include a
".config".)

Otherwise, I couldn't tell you what it might be. Make sure all your
messages end with '\n', make sure you're not accidentally using the wrong
formatting codes and it's backing over previous output with ^H or
something. You could confirm or rule out the possibility of overflowing
the printk buffers by writing a dummy module with a tight loop of nothing
but printk statements with counters to see if you can get it to asplode.


It seems that my 'all KERN_DEBUG<space>"some string here"' was off by
one - there was one, the newest, with a comma after the KERN_DEBUG.
Removing it solved the problem.

Many thanks for the assistance.

--
Mark Hull-Richter, Linux Kernel Engineer
DATAllegro (www.datallegro.com)
85 Enterprise, Second Floor, Aliso Viejo, CA 92656
949-680-3082 - Office 949-330-7691 - fax
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