From 567df96ae1f966f3edc02f5296fcb250b6b0a841 Mon Sep 17 00:00:00 2001
From: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Sun, 16 Aug 2015 15:16:57 +0200
Subject: [PATCH gnumach 10/12] fu_locking_issues

---
 vm/vm_map.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/vm/vm_map.c b/vm/vm_map.c
index a26eaff..d4ae0f1 100644
--- a/vm/vm_map.c
+++ b/vm/vm_map.c
@@ -2126,6 +2126,7 @@ start_pass_1:
 	for (entry = tmp_entry;;) {
 		vm_size_t	sub_size = (entry->vme_end - entry->vme_start);
 		vm_map_entry_t	next = entry->vme_next;
+		vm_object_t	object;
 
 		if ( ! (entry->protection & VM_PROT_WRITE)) {
 			vm_map_unlock(dst_map);
@@ -2161,10 +2162,13 @@ start_pass_1:
 		/*
 		 *	Check for permanent objects in the destination.
 		 */
-
-		if ((entry->object.vm_object != VM_OBJECT_NULL) &&
-			   !entry->object.vm_object->temporary)
-			contains_permanent_objects = TRUE;
+		object = entry->object.vm_object;
+		if ((object != VM_OBJECT_NULL)
+		    && ! contains_permanent_objects) {
+			vm_object_lock(object);
+			contains_permanent_objects = object->temporary;
+			vm_object_unlock(object);
+		}
 
 		size -= sub_size;
 		entry = next;
@@ -2224,6 +2228,7 @@ start_pass_1:
 		vm_map_entry_t	copy_entry = vm_map_copy_first_entry(copy);
 		vm_size_t	copy_size = (copy_entry->vme_end - copy_entry->vme_start);
 		vm_object_t	object;
+		int		temporary;
 
 		entry = tmp_entry;
 		size = (entry->vme_end - entry->vme_start);
@@ -2279,8 +2284,15 @@ start_pass_1:
 		 */
 
 		object = entry->object.vm_object;
+		temporary = 0;
+		if (object != VM_OBJECT_NULL) {
+			vm_object_lock(object);
+			temporary = object->temporary;
+			vm_object_unlock(object);
+		}
+
 		if (!entry->is_shared &&
-		    ((object == VM_OBJECT_NULL) || object->temporary)) {
+		    ((object == VM_OBJECT_NULL) || temporary)) {
 			vm_object_t	old_object = entry->object.vm_object;
 			vm_offset_t	old_offset = entry->offset;
 
-- 
2.1.4