svn commit: r255849 - head/sys/amd64/amd64

[Konstantin Belousov]

Author: kib
Date: Tue Sep 24 13:52:47 2013
New Revision: 255849
URL: http://svnweb.freebsd.org/changeset/base/255849

Log:
  In pmap_clear_modify(), initialize pvh even for fictitious managed
  page, otherwise the small mappings loop would use uninitialized value.
  Note that currently pmap_clear_modify() is not called for fictitious
  pages.
  
  Sponsored by:	The FreeBSD Foundation
  Approved by:	re (glebius)

Modified:
  head/sys/amd64/amd64/pmap.c

Modified: head/sys/amd64/amd64/pmap.c
==============================================================================
--- head/sys/amd64/amd64/pmap.c	Tue Sep 24 13:46:13 2013	(r255848)
+++ head/sys/amd64/amd64/pmap.c	Tue Sep 24 13:52:47 2013	(r255849)
@@ -5331,13 +5331,13 @@ pmap_clear_modify(vm_page_t m)
 	 */
 	if ((m->aflags & PGA_WRITEABLE) == 0)
 		return;
+	pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m));
 	rw_rlock(&pvh_global_lock);
 	lock = VM_PAGE_TO_PV_LIST_LOCK(m);
 	rw_wlock(lock);
 restart:
 	if ((m->flags & PG_FICTITIOUS) != 0)
 		goto small_mappings;
-	pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m));
 	TAILQ_FOREACH_SAFE(pv, &pvh->pv_list, pv_next, next_pv) {
 		pmap = PV_PMAP(pv);
 		if (!PMAP_TRYLOCK(pmap)) {