From 3fb2fbdd20840b8b4c4d96fdd8946283ec33d73d Mon Sep 17 00:00:00 2001
From: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Mon, 17 Aug 2015 14:04:51 +0200
Subject: [PATCH gnumach 11/12] fu_locking_issues

---
 vm/vm_map.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/vm/vm_map.c b/vm/vm_map.c
index d4ae0f1..9098dfd 100644
--- a/vm/vm_map.c
+++ b/vm/vm_map.c
@@ -3235,11 +3235,15 @@ kern_return_t vm_map_copyin(
 		/*
 		 *	Attempt non-blocking copy-on-write optimizations.
 		 */
-
+		if (src_object)
+			vm_object_lock(src_object);
 		if (src_destroy &&
 		    (src_object == VM_OBJECT_NULL ||
 		     (src_object->temporary && !src_object->use_shared_copy)))
 		{
+		    if (src_object)
+			vm_object_unlock(src_object);
+
 		    /*
 		     * If we are destroying the source, and the object
 		     * is temporary, and not shared writable,
@@ -3259,6 +3263,9 @@ kern_return_t vm_map_copyin(
 		    goto CopySuccessful;
 		}
 
+		if (src_object)
+			vm_object_unlock(src_object);
+
 		if (!was_wired &&
 		    vm_object_copy_temporary(
 				&new_entry->object.vm_object,
-- 
2.1.4