Re: agp.ko panic: vm_fault: fault on nofault entry, addr: deadc000

On 25/10/2007, John Baldwin <jhb_at_freebsd.org> wrote:
> On Saturday 20 October 2007 10:30:31 pm pluknet wrote:
> > Hello all.
> >
> > I could produce panic while kldunload'ing agp.ko.
> >
> > It's on 7.0-CURRENT from Oct 11 (just before RELENG_7), i386, UP,
> > Intel 82855GME (855GME GMCH) SVGA controller.
> > Some debugging below:
> >
> > panic: vm_fault: fault on nofault entry, addr: deadc000
> > KDB: enter: panic
>
> This is caused by the agp_i810() driver calling agp_generic_detach() first
> which frees the memory resource for the aperture.  Other AGP drivers do the
> same thing.  I think the proper fix is to split agp_generic_detach() into two
> pieces.  The first part would do a destroy_dev() of the /dev node and the
> various agp_foo_detach() methods would call that first.  The rest
> agp_generic_detach() would be called at the end of the agp_foo_detach()
> methods.
Yes, I forgot to note that there was a message about memory leakage on panic.

>
> A possible patch (untested) is at
> http://www.FreeBSD.org/~jhb/patches/agp_detach.patch and included below:
Thank you. This patch fixes my issue.
Now all three modules (drm, agp, i915) unloaded without a panic.

>
> --
> John Baldwin
>

wbr,
pluknet