Index: sys/sparc64/sparc64/pmap.c
===================================================================
--- sys/sparc64/sparc64/pmap.c	(revision 250855)
+++ sys/sparc64/sparc64/pmap.c	(working copy)
@@ -1843,6 +1843,8 @@ pmap_copy_page(vm_page_t msrc, vm_page_t mdst)
 	vm_paddr_t psrc;
 	struct tte *tp;
 
+	if ((msrc->oflags & VPO_BUSY) == 0)
+		VM_OBJECT_ASSERT_LOCKED(msrc->object);
 	KASSERT((mdst->flags & PG_FICTITIOUS) == 0,
 	    ("pmap_copy_page: fake dst page"));
 	KASSERT((msrc->flags & PG_FICTITIOUS) == 0,
Index: sys/ia64/ia64/pmap.c
===================================================================
--- sys/ia64/ia64/pmap.c	(revision 250855)
+++ sys/ia64/ia64/pmap.c	(working copy)
@@ -2009,6 +2009,9 @@ pmap_copy_page(vm_page_t msrc, vm_page_t mdst)
 {
 	void *dst, *src;
 
+	if ((msrc->oflags & VPO_BUSY) == 0)
+		VM_OBJECT_ASSERT_LOCKED(msrc->object);
+
 	src = (void *)pmap_page_to_va(msrc);
 	dst = (void *)pmap_page_to_va(mdst);
 	bcopy(src, dst, PAGE_SIZE);
Index: sys/vm/vm_fault.c
===================================================================
--- sys/vm/vm_fault.c	(revision 250855)
+++ sys/vm/vm_fault.c	(working copy)
@@ -1318,7 +1318,7 @@ vm_fault_copy_entry(vm_map_t dst_map, vm_map_t src
 		 * (Because the source is wired down, the page will be in
 		 * memory.)
 		 */
-		VM_OBJECT_WLOCK(src_object);
+		VM_OBJECT_RLOCK(src_object);
 		object = src_object;
 		pindex = src_pindex + dst_pindex;
 		while ((src_m = vm_page_lookup(object, pindex)) == NULL &&
@@ -1327,15 +1327,15 @@ vm_fault_copy_entry(vm_map_t dst_map, vm_map_t src
 			/*
 			 * Allow fallback to backing objects if we are reading.
 			 */
-			VM_OBJECT_WLOCK(backing_object);
+			VM_OBJECT_RLOCK(backing_object);
 			pindex += OFF_TO_IDX(object->backing_object_offset);
-			VM_OBJECT_WUNLOCK(object);
+			VM_OBJECT_RUNLOCK(object);
 			object = backing_object;
 		}
 		if (src_m == NULL)
 			panic("vm_fault_copy_wired: page missing");
 		pmap_copy_page(src_m, dst_m);
-		VM_OBJECT_WUNLOCK(object);
+		VM_OBJECT_RUNLOCK(object);
 		dst_m->valid = VM_PAGE_BITS_ALL;
 		dst_m->dirty = VM_PAGE_BITS_ALL;
 		VM_OBJECT_WUNLOCK(dst_object);
Index: sys/i386/i386/pmap.c
===================================================================
--- sys/i386/i386/pmap.c	(revision 250855)
+++ sys/i386/i386/pmap.c	(working copy)
@@ -4185,6 +4185,9 @@ pmap_copy_page(vm_page_t src, vm_page_t dst)
 {
 	struct sysmaps *sysmaps;
 
+	if ((src->oflags & VPO_BUSY) == 0)
+		VM_OBJECT_ASSERT_LOCKED(src->object);
+
 	sysmaps = &sysmaps_pcpu[PCPU_GET(cpuid)];
 	mtx_lock(&sysmaps->lock);
 	if (*sysmaps->CMAP1)
Index: sys/i386/xen/pmap.c
===================================================================
--- sys/i386/xen/pmap.c	(revision 250855)
+++ sys/i386/xen/pmap.c	(working copy)
@@ -3432,6 +3432,9 @@ pmap_copy_page(vm_page_t src, vm_page_t dst)
 {
 	struct sysmaps *sysmaps;
 
+	if ((src->oflags & VPO_BUSY) == 0)
+		VM_OBJECT_ASSERT_LOCKED(src->object);
+
 	sysmaps = &sysmaps_pcpu[PCPU_GET(cpuid)];
 	mtx_lock(&sysmaps->lock);
 	if (*sysmaps->CMAP1)
Index: sys/amd64/amd64/pmap.c
===================================================================
--- sys/amd64/amd64/pmap.c	(revision 250855)
+++ sys/amd64/amd64/pmap.c	(working copy)
@@ -4229,9 +4229,14 @@ pmap_zero_page_idle(vm_page_t m)
 void
 pmap_copy_page(vm_page_t msrc, vm_page_t mdst)
 {
-	vm_offset_t src = PHYS_TO_DMAP(VM_PAGE_TO_PHYS(msrc));
-	vm_offset_t dst = PHYS_TO_DMAP(VM_PAGE_TO_PHYS(mdst));
+	vm_offset_t dst, src;
 
+	if ((msrc->oflags & VPO_BUSY) == 0)
+		VM_OBJECT_ASSERT_LOCKED(msrc->object);
+
+	src = PHYS_TO_DMAP(VM_PAGE_TO_PHYS(msrc));
+	dst = PHYS_TO_DMAP(VM_PAGE_TO_PHYS(mdst));
+
 	pagecopy((void *)src, (void *)dst);
 }
 
Index: sys/powerpc/booke/pmap.c
===================================================================
--- sys/powerpc/booke/pmap.c	(revision 250855)
+++ sys/powerpc/booke/pmap.c	(working copy)
@@ -2127,6 +2127,9 @@ mmu_booke_copy_page(mmu_t mmu, vm_page_t sm, vm_pa
 {
 	vm_offset_t sva, dva;
 
+	if ((ms->oflags & VPO_BUSY) == 0)
+		VM_OBJECT_ASSERT_LOCKED(ms->object);
+
 	sva = copy_page_src_va;
 	dva = copy_page_dst_va;
 
Index: sys/powerpc/aim/mmu_oea.c
===================================================================
--- sys/powerpc/aim/mmu_oea.c	(revision 250855)
+++ sys/powerpc/aim/mmu_oea.c	(working copy)
@@ -1050,6 +1050,9 @@ moea_copy_page(mmu_t mmu, vm_page_t msrc, vm_page_
 	vm_offset_t	dst;
 	vm_offset_t	src;
 
+	if ((msrc->oflags & VPO_BUSY) == 0)
+		VM_OBJECT_ASSERT_LOCKED(msrc->object);
+
 	dst = VM_PAGE_TO_PHYS(mdst);
 	src = VM_PAGE_TO_PHYS(msrc);
 
Index: sys/powerpc/aim/mmu_oea64.c
===================================================================
--- sys/powerpc/aim/mmu_oea64.c	(revision 250855)
+++ sys/powerpc/aim/mmu_oea64.c	(working copy)
@@ -1097,6 +1097,9 @@ moea64_copy_page(mmu_t mmu, vm_page_t msrc, vm_pag
 	vm_offset_t	dst;
 	vm_offset_t	src;
 
+	if ((msrc->oflags & VPO_BUSY) == 0)
+		VM_OBJECT_ASSERT_LOCKED(msrc->object);
+
 	dst = VM_PAGE_TO_PHYS(mdst);
 	src = VM_PAGE_TO_PHYS(msrc);
 
Index: sys/arm/arm/pmap-v6.c
===================================================================
--- sys/arm/arm/pmap-v6.c	(revision 250855)
+++ sys/arm/arm/pmap-v6.c	(working copy)
@@ -3729,6 +3729,9 @@ void
 pmap_copy_page(vm_page_t src, vm_page_t dst)
 {
 
+	if ((src->oflags & VPO_BUSY) == 0)
+		VM_OBJECT_ASSERT_LOCKED(src->object);
+
 	if (_arm_memcpy && PAGE_SIZE >= _min_memcpy_size &&
 	    _arm_memcpy((void *)VM_PAGE_TO_PHYS(dst),
 	    (void *)VM_PAGE_TO_PHYS(src), PAGE_SIZE, IS_PHYSICAL) == 0)
Index: sys/arm/arm/pmap.c
===================================================================
--- sys/arm/arm/pmap.c	(revision 250855)
+++ sys/arm/arm/pmap.c	(working copy)
@@ -4411,6 +4411,9 @@ pmap_copy_page(vm_page_t src, vm_page_t dst)
 	vm_offset_t srcpg, dstpg;
 #endif
 
+	if ((src->oflags & VPO_BUSY) == 0)
+		VM_OBJECT_ASSERT_LOCKED(src->object);
+
 	cpu_dcache_wbinv_all();
 	cpu_l2cache_wbinv_all();
 	if (_arm_memcpy && PAGE_SIZE >= _min_memcpy_size &&
Index: sys/mips/mips/pmap.c
===================================================================
--- sys/mips/mips/pmap.c	(revision 250855)
+++ sys/mips/mips/pmap.c	(working copy)
@@ -2551,9 +2551,14 @@ void
 pmap_copy_page(vm_page_t src, vm_page_t dst)
 {
 	vm_offset_t va_src, va_dst;
-	vm_paddr_t phys_src = VM_PAGE_TO_PHYS(src);
-	vm_paddr_t phys_dst = VM_PAGE_TO_PHYS(dst);
+	vm_paddr_t phys_dst, phys_src;
 
+	if ((src->oflags & VPO_BUSY) == 0)
+		VM_OBJECT_ASSERT_LOCKED(src->object);
+
+	phys_src = VM_PAGE_TO_PHYS(src);
+	phys_dst = VM_PAGE_TO_PHYS(dst);
+
 	if (MIPS_DIRECT_MAPPABLE(phys_src) && MIPS_DIRECT_MAPPABLE(phys_dst)) {
 		/* easy case, all can be accessed via KSEG0 */
 		/*