svn commit: r329705 - stable/11/sys/vm

[Konstantin Belousov]

Author: kib
Date: Wed Feb 21 11:28:05 2018
New Revision: 329705
URL: https://svnweb.freebsd.org/changeset/base/329705

Log:
  MFC r329254:
  Ensure memory consistency on COW.

Modified:
  stable/11/sys/vm/vm_fault.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/vm/vm_fault.c
==============================================================================
--- stable/11/sys/vm/vm_fault.c	Wed Feb 21 11:26:59 2018	(r329704)
+++ stable/11/sys/vm/vm_fault.c	Wed Feb 21 11:28:05 2018	(r329705)
@@ -1133,6 +1133,10 @@ readrest:
 				 */
 				pmap_copy_page(fs.m, fs.first_m);
 				fs.first_m->valid = VM_PAGE_BITS_ALL;
+				if ((fault_flags & VM_FAULT_WIRE) == 0) {
+					prot &= ~VM_PROT_WRITE;
+					fault_type &= ~VM_PROT_WRITE;
+				}
 				if (wired && (fault_flags &
 				    VM_FAULT_WIRE) == 0) {
 					vm_page_lock(fs.first_m);