William Cohen writes:
> Tom Zanussi wrote:
> > Hi,
> >
> > I've been having some fun playing around with maps keyed on stack
> > traces (very cool to be able to do this) and have checked into
> > systemtap.samples a systemtap script (kmalloc-stacks.stp) and a perl
> > script (kmalloc-top) that in combination continuously track the
> > different execution paths to kmalloc(). It keeps counts of the
> > different execution paths in a systemtap hash, and periodically dumps
> > the hash contents (and clears the hash table) to the perl script,
> > which rehashes them in user space. At the end of the run (Ctrl-C), it
> > sorts the accumulated hash table and filters out any stacks that
> > contain any of the user-supplied regexps (-e option), which helps cut
> > down on noise e.g.
> >
> > # ./kmalloc-top -e sys_select,alloc_skb
> >
> > Here's an example of the output (gathered over a kernel compile):
>
> Hi Tom, I have been playing around with the kmalloc example you checked
> in. When running it, I have seen a couple panics like the one in the
> photo at:
>
> http://people.redhat.com/wcohen/100_0405.jpg
>
> This is on a pentium III machine running the rawhide with the current
> kernel:
>
> Linux trek.devel.redhat.com 2.6.13-1.1555_FC5smp #1 SMP Wed Sep 14
> 15:59:49 EDT 2005 i686 i686 i386 GNU/Linux
>
>
Hmm, I haven't seen anything like that on my machine, a Pentium 4
running 2.6.12-1.1447_FC4.
Is there anything in particular you do to make it happen? The
sytemtap script itself is pretty simple and doesn't do anything out of
the ordinary as far as I can tell. I see _stp_map_del() in the trace
- is that always the case?
Tom