[patch] corrupt memstat_kvm_malloc(3) output and dtrace

[John Baldwin]

On Wednesday 06 May 2009 1:00:09 am Ben Kelly wrote:
> On May 5, 2009, at 10:18 AM, Ben Kelly wrote:
> > While debugging a problem recently with Alexander Leidinger we  
> > noticed that crashinfo(8) was producing corrupt vmstat -m output.   
> > After doing some digging it appears that memstat_kvm_malloc(3) might  
> > have been broken by this commit:
> >
> >  http://svn.freebsd.org/viewvc/base?view=revision&revision=179222
> >
> > The problem is that memstat_kvm_malloc(3) assumes that  
> > malloc_type_internal starts with an array of malloc_types_stats  
> > structures.  This assumption is no longer true, though, as  
> > mti_probes was inserted at the start of the structure.
> >
> > It appears that this (untested) patch might fix the problem:
> >
> >  http://www.wanderview.com/svn/public/misc/zfs/vmstat_kvm_malloc.diff
> >
> > I'm not very familiar with dtrace, though.  Does anyone know if this  
> > would cause problems?
> 
> Just FYI, I was able to recompile and test this patch tonight.  It  
> seems to have fixed vmstat -M $core -m output on my machine.

I think that it would be better to update memstat_kvm_malloc(3) though.  I'm 
also curious why libmemstat isn't just using malloc_types_internal directly.

-- 
John Baldwin