Re: panic: Memory modified after free

On Tue, Jan 31, 2006 at 04:45:22PM -0500, Kris Kennaway wrote:
> On Tue, Jan 31, 2006 at 01:38:34PM -0800, Steve Kargl wrote:
> > On Tue, Jan 31, 2006 at 04:33:32PM -0500, Kris Kennaway wrote:
> > > On Tue, Jan 31, 2006 at 01:22:09PM -0800, Steve Kargl wrote:
> > > > The system is a dual proc Tyan K8S Pro with 12 GB of memory.
> > > > The kernel is UP.  This was recorded by hand. I have the crash dump.
> > > > 
> > > > Memory modified after free 0xffffff02505e0c00(504) val=deadc0dd _at_
> > > > 0xffffff02505e0cd0
> > > > 
> > > > panic: Most recently used by DEVFS1
> > > 
> > > Set up memguard to watch this malloc type in order to obtain useful
> > > debugging.
> > > 
> > 
> > OK, I've read the memguard manpage and it says to add
> > 
> > vm.memguard.desc=<memory_type>
> > 
> > to /boot/loader.conf.  Where to I get info for what <memory_type>
> > actually means?
> 
> Look at the relevant MALLOC_DEFINE() in the source, it's the second
> field (see malloc(9)).  This should probably be clarified in the
> memguard manpage.
> 

Thanks.  I've found the memory_type, and I rebuilding a kernel
now with DEBUG_MEMGUARD.  I can get the system to panic with 
5 minutes, so I should have more information shortly.


-- 
Steve