On Mon, Mar 13, 2006 at 09:16:59AM -0500, Andreas Wrede wrote:
> On Mon, Jan 23, 2006 at 12:52:37PM +0100, Manuel Bouyer wrote:
> 
> >On Mon, Jan 23, 2006 at 12:41:54PM +0100, Manuel Bouyer wrote:
> >> >
> >> > Panic message:
> >> >
> >> > panic: m_makewritable: length changed
> >> > Stopped at      netbsd:cpu_Debugger+0x4:        leave
> >> > cpu_Debugger(c03f8d38,38,c03f8ce8,c03f8d38,0) at  
> >netbsd:cpu_Debugger+0x4
> >> > panic(c0331900,1,0,0,0) at netbsd:panic+0x121
> >> > m_makewritable(c03f8d38,0,3b9aca00,1,c0871500) at  
> >netbsd:m_makewritable+0x6b
> >> > fr_check_wrapper(0,c03f8d38,c072d038,1,c0871800) at  
> >netbsd:fr_check_wrapper+0x1b
> >>
> >> This is an internal diagnostig to m_makewritable(). Now, I see this
> >> check doesn't check the error code returned by m_copyback0(), so  
> >it's
> >> possible it's triggered because of ressources shortage on mbuf pool.
> >
> >After reading mbuf(9) m_makewritable() should return the mbuf chain
> >unmodified in case of error. So it's probably m_copyback0() which  
> >is wrong
> >here.
> 
> I am now getting the same panic. DomU is running  3.99.16 as of March  
> 8th, Dom0 is  3.99.16 from March 2nd. Was this resolved somehow?
> 
> panic: m_makewritable: length changed

Not that I know. But AFAIK it's not an issue with m_makewritable() or
m_copyback0(), not in Xen itself (it just happens that Xen can triggers
it). Can you add some debug checks in m_copyback0() and m_makewritable()
to see what's really happening here ?

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
     NetBSD: 26 ans d'experience feront toujours la difference
--