Re: kern/53072: netbsd-8 regression: startx (nv driver) crashes system

[Roy Bixler <rcbixler%nyx.net@localhost>]

On Mon, Mar 05, 2018 at 07:10:00PM +0000, matthew green wrote:
> The following reply was made to PR kern/53072; it has been noted by GNATS.
> 
> From: matthew green <mrg%eterna.com.au@localhost>
> To: gnats-bugs%NetBSD.org@localhost, rcbixler%nyx.net@localhost, bsiegert%netbsd.org@localhost
> Cc: kern-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
>     netbsd-bugs%netbsd.org@localhost
> Subject: re: kern/53072: netbsd-8 regression: startx (nv driver) crashes system
> Date: Tue, 06 Mar 2018 06:06:41 +1100
> 
>  can you try this patch?  it's x86/pmap.c 1.267 which was
>  missed in the pullup.

I applied the patch to the source tree pulled from netbsd-8 as of
2018-02-27 1000Z and X with the nv driver works again.

>  Index: pmap.c
>  ===================================================================
>  RCS file: /cvsroot/src/sys/arch/x86/x86/pmap.c,v
>  retrieving revision 1.245.6.2
>  diff -p -u -u -r1.245.6.2 pmap.c
>  --- pmap.c	27 Feb 2018 09:07:33 -0000	1.245.6.2
>  +++ pmap.c	5 Mar 2018 19:02:45 -0000
>  @@ -1737,8 +1737,8 @@ pmap_pp_needs_pve(struct pmap_page *pp)
>   	 * since the first pv entry is stored in the pmap_page.
>   	 */
>   
>  -	return (pp->pp_flags & PP_EMBEDDED) != 0 ||
>  -		!LIST_EMPTY(&pp->pp_head.pvh_list);
>  +	return pp && ((pp->pp_flags & PP_EMBEDDED) != 0 ||
>  +	    !LIST_EMPTY(&pp->pp_head.pvh_list));
>   }
>   
>   /*
>  @@ -4123,7 +4123,7 @@ pmap_enter_ma(struct pmap *pmap, vaddr_t
>   	 */
>   
>   	bool needpves = pmap_pp_needs_pve(new_pp);
>  -	if (new_pp && needpves) {
>  +	if (needpves) {
>   		new_pve = pool_cache_get(&pmap_pv_cache, PR_NOWAIT);
>   		new_sparepve = pool_cache_get(&pmap_pv_cache, PR_NOWAIT);
>   	} else {
>  

-- 
Roy Bixler <rcbixler%nyx.net@localhost>
"The fundamental principle of science, the definition almost, is this: the
sole test of the validity of any idea is experiment."
-- Richard P. Feynman