7.2 Stable Crash - possibly related to if_re

[Norbert Papke]

On October 31, 2009, Pyun YongHyeon wrote:
> On Fri, Oct 30, 2009 at 06:23:51PM -0700, Norbert Papke wrote:
> > On October 30, 2009, Pyun YongHyeon wrote:
> > > On Thu, Oct 29, 2009 at 09:56:19PM -0700, Norbert Papke wrote:
> > > > This occurred shortly after "scp"ing from a VirtualBox VM to the
> > > > host. The file transfer got stuck.  The "re" interface stopped
> > > > working. Shortly afterwards, the host crashed.  The "re" interface
> > > > was used by the host, the guest was using a different NIC in bridged
> > > > mode.
> > > >
> > > >
> > > > FreeBSD proven.lan 7.2-STABLE FreeBSD 7.2-STABLE #5 r198666: Thu Oct
> > > > 29 18:36:57 PDT 2009
> > > >
> > > > Fatal trap 12: page fault while in kernel mode
> > > > cpuid = 0; apic id = 00
> > > > fault virtual address   = 0x18
> > >
> > > It looks like a NULL pointer dereference, possibly mbuf related
> > > one.
> > >
> > > > fault code              = supervisor write data, page not present
> > > > instruction pointer     = 0x8:0xffffffff80d476ee
> > > > stack pointer           = 0x10:0xffffff8000078ae0
> > > > frame pointer           = 0x10:0xffffff8000078b40
> > > > code segment            = base 0x0, limit 0xfffff, type 0x1b
> > > >                         = DPL 0, pres 1, long 1, def32 0, gran 1
> > > > processor eflags        = interrupt enabled, resume, IOPL = 0
> > > > current process         = 18 (swi5: +)


> > > By chance, did you stop the re0 interface with ifconfig when you
> > > noticed the file transfer got stuck?
> >
> > It is possible.  I had it happen twice.  The first time I definitely
> > tried to "down" re.  I cannot recall what I did the second time.  The
> > crash dump is from the second time.
>
> Ok, then would you try attached patch?

I have been running with the patch for a couple of days.  Although I can still 
reproduce the lock-up of the network stack, I have not been able to reproduce 
the panic.  The patch does what it is supposed to do.

I will continue to try to come up with a better test case for the file 
transfer problem.  However, I no longer suspect "re" as a cause.

Thank you very much for your help.

Cheers,

-- Norbert Papke.
   npapke at acm.org


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