Index: sys/vm/vm_fault.c
===================================================================
--- sys/vm/vm_fault.c	(revision 297486)
+++ sys/vm/vm_fault.c	(working copy)
@@ -426,6 +426,8 @@ fast_failed:
 		 * If the object is dead, we stop here
 		 */
 		if (fs.object->flags & OBJ_DEAD) {
+printf("%d vm_fault OBJ_DEAD %p\n", curproc->p_pid, fs.object);
+stack_print(&fs.object->dead_stack);
 			unlock_and_deallocate(&fs);
 			return (KERN_PROTECTION_FAILURE);
 		}
Index: sys/vm/vm_object.c
===================================================================
--- sys/vm/vm_object.c	(revision 297486)
+++ sys/vm/vm_object.c	(working copy)
@@ -265,6 +265,7 @@ _vm_object_allocate(objtype_t type, vm_pindex_t si
 #if VM_NRESERVLEVEL > 0
 	LIST_INIT(&object->rvq);
 #endif
+stack_zero(&object->dead_stack);
 }
 
 /*
Index: sys/vm/vm_object.h
===================================================================
--- sys/vm/vm_object.h	(revision 297486)
+++ sys/vm/vm_object.h	(working copy)
@@ -74,6 +74,7 @@
 
 #include <vm/_vm_radix.h>
 
+#include <sys/stack.h>
 /*
  *	Types defined:
  *
@@ -110,8 +111,8 @@ struct vm_object {
 	int shadow_count;		/* how many objects that this is a shadow for */
 	vm_memattr_t memattr;		/* default memory attribute for pages */
 	objtype_t type;			/* type of pager */
-	u_short flags;			/* see below */
-	u_short pg_color;		/* (c) color of first page in obj */
+	u_int flags;			/* see below */
+	u_int pg_color;		/* (c) color of first page in obj */
 	u_int paging_in_progress;	/* Paging (in or out) so don't collapse or destroy */
 	int resident_page_count;	/* number of resident pages */
 	struct vm_object *backing_object; /* object that I'm a shadow of */
@@ -174,6 +175,7 @@ struct vm_object {
 	} un_pager;
 	struct ucred *cred;
 	vm_ooffset_t charge;
+struct stack dead_stack;
 };
 
 /*
@@ -253,6 +255,8 @@ static __inline void
 vm_object_set_flag(vm_object_t object, u_short bits)
 {
 
+VM_OBJECT_ASSERT_WLOCKED(object);
+if ((bits & OBJ_DEAD) != 0) stack_save(&object->dead_stack);
 	object->flags |= bits;
 }