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

[matthew green <mrg%eterna.com.au@localhost>]

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.
 
 Benny, this might fix your new problem too.  can you also
 test it?
 
 thanks.
 
 
 .mrg.
 
 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 {