bugs in contigmalloc*() related to "page not found in hash" panics

[Sean Farley]

On Wed, 10 Nov 2004, Matthew Dillon wrote:

>    I've tracked down several bugs in contigmalloc*() in DragonFly
>    based on kernel cores provided by David Rhodus.  These bugs have
>    just been addressed in DFly but also need to be addressed in
>    FreeBSD-4, and at least some work must also be done in FreeBSD-5/6.
>    So someone needs to take up the ball and deal with this in FreeBSD.
>
>    Here is the DragonFly commit.
>
>    http://www.dragonflybsd.org/cvsweb/src/sys/vm/vm_contig.c.diff?r1=1.10&r2=1.11&f=u
>
>    FreeBSD-4:
>
> 	FreeBSD-4 is in the same situation that DFly was in and requires
> 	the same fixes as the above patch, though note that in FreeBSD-4
> 	the contigmalloc() code is in vm_page.c, not vm_contig.c.

I tried the patch in the hopes it would fix my Nvidia-driver
crash-on-demand system.  :)  While my system appears stable without the
Nvidia driver but with this patch, my system can still crash easily with
the Nvidia driver.  It usually dies with a:

     Fatal trap 12: page fault while in kernel mode
     fault virtual address   = 0x30
     fault code              = supervisor read, page not present

Two "page not found in hash" panics that I believe are related to the
Nvidia driver:
http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/71086
http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/72539

The first PR (mine) asks about a change in pmap_remove() that was later
removed from FreeBSD-4 but left in FreeBSD-5.  If anyone knows why this
happened, I would be interested in knowing.

Sean
-- 
sean-freebsd at farley.org