- Lock the vm_object when performing vm_object_pip_wakeupn().

 - Assert that the vm_object lock is held in vm_object_pip_wakeupn().
 - Add a new macro VM_OBJECT_LOCK_ASSERT().

3 files changed, 7 insertions, 1 deletions

diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c
index 0fb5d22..997e682 100644
--- a/sys/vm/swap_pager.c
+++ b/sys/vm/swap_pager.c
@@ -1613,8 +1613,11 @@ swp_pager_async_iodone(bp)
 	 * adjust pip.  NOTE: the original parent may still have its own
 	 * pip refs on the object.
 	 */
-	if (object)
+	if (object != NULL) {
+		VM_OBJECT_LOCK(object);
 		vm_object_pip_wakeupn(object, bp->b_npages);
+		VM_OBJECT_UNLOCK(object);
+	}
 
 	/*
 	 * release the physical I/O buffer
diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
index a079d83..4f784b0 100644
--- a/sys/vm/vm_object.c
+++ b/sys/vm/vm_object.c
@@ -296,6 +296,7 @@ void
 vm_object_pip_wakeupn(vm_object_t object, short i)
 {
 	GIANT_REQUIRED;
+	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 	if (i)
 		object->paging_in_progress -= i;
 	if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
diff --git a/sys/vm/vm_object.h b/sys/vm/vm_object.h
index 4f4f77b..9dd0ab9 100644
--- a/sys/vm/vm_object.h
+++ b/sys/vm/vm_object.h
@@ -171,6 +171,8 @@ extern vm_object_t kernel_object;	/* the single kernel object */
 extern vm_object_t kmem_object;
 
 #define	VM_OBJECT_LOCK(object)		mtx_lock(&(object)->mtx)
+#define	VM_OBJECT_LOCK_ASSERT(object, type) \
+					mtx_assert(&(object)->mtx, (type))
 #define	VM_OBJECT_UNLOCK(object)	mtx_unlock(&(object)->mtx)
 
 #define	vm_object_lock(object) \