Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching

Pull livepatching updates from Jiri Kosina:

 - livepatching kselftests improvements from Joe Lawrence and Miroslav
   Benes

 - making use of gcc's -flive-patching option when available, from
   Miroslav Benes

 - kobject handling cleanups, from Petr Mladek

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
  livepatch: Remove duplicated code for early initialization
  livepatch: Remove custom kobject state handling
  livepatch: Convert error about unsupported reliable stacktrace into a warning
  selftests/livepatch: Add functions.sh to TEST_PROGS_EXTENDED
  kbuild: use -flive-patching when CONFIG_LIVEPATCH is enabled
  selftests/livepatch: use TEST_PROGS for test scripts

Makefile

@@ -811,6 +811,10 @@ KBUILD_CFLAGS_KERNEL += -ffunction-sections -fdata-sections
 LDFLAGS_vmlinux += --gc-sections
 endif
 
+ifdef CONFIG_LIVEPATCH
+KBUILD_CFLAGS += $(call cc-option, -flive-patching=inline-clone)
+endif
+
 # arch Makefile may override CC so keep this after arch Makefile is included
 NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
 

include/linux/livepatch.h

@@ -86,7 +86,6 @@ struct klp_func {
 	struct list_head node;
 	struct list_head stack_node;
 	unsigned long old_size, new_size;
-	bool kobj_added;
 	bool nop;
 	bool patched;
 	bool transition;
@@ -141,7 +140,6 @@ struct klp_object {
 	struct list_head func_list;
 	struct list_head node;
 	struct module *mod;
-	bool kobj_added;
 	bool dynamic;
 	bool patched;
 };
@@ -170,7 +168,6 @@ struct klp_patch {
 	struct list_head list;
 	struct kobject kobj;
 	struct list_head obj_list;
-	bool kobj_added;
 	bool enabled;
 	bool forced;
 	struct work_struct free_work;

kernel/livepatch/core.c

@@ -426,7 +426,13 @@ static void klp_free_object_dynamic(struct klp_object *obj)
 	kfree(obj);
 }
 
-static struct klp_object *klp_alloc_object_dynamic(const char *name)
+static void klp_init_func_early(struct klp_object *obj,
+				struct klp_func *func);
+static void klp_init_object_early(struct klp_patch *patch,
+				  struct klp_object *obj);
+
+static struct klp_object *klp_alloc_object_dynamic(const char *name,
+						   struct klp_patch *patch)
 {
 	struct klp_object *obj;
 
@@ -442,7 +448,7 @@ static struct klp_object *klp_alloc_object_dynamic(const char *name)
 		}
 	}
 
-	INIT_LIST_HEAD(&obj->func_list);
+	klp_init_object_early(patch, obj);
 	obj->dynamic = true;
 
 	return obj;
@@ -471,6 +477,7 @@ static struct klp_func *klp_alloc_func_nop(struct klp_func *old_func,
 		}
 	}
 
+	klp_init_func_early(obj, func);
 	/*
 	 * func->new_func is same as func->old_func. These addresses are
 	 * set when the object is loaded, see klp_init_object_loaded().
@@ -490,11 +497,9 @@ static int klp_add_object_nops(struct klp_patch *patch,
 	obj = klp_find_object(patch, old_obj);
 
 	if (!obj) {
-		obj = klp_alloc_object_dynamic(old_obj->name);
+		obj = klp_alloc_object_dynamic(old_obj->name, patch);
 		if (!obj)
 			return -ENOMEM;
-
-		list_add_tail(&obj->node, &patch->obj_list);
 	}
 
 	klp_for_each_func(old_obj, old_func) {
@@ -505,8 +510,6 @@ static int klp_add_object_nops(struct klp_patch *patch,
 		func = klp_alloc_func_nop(old_func, obj);
 		if (!func)
 			return -ENOMEM;
-
-		list_add_tail(&func->node, &obj->func_list);
 	}
 
 	return 0;
@@ -588,13 +591,7 @@ static void __klp_free_funcs(struct klp_object *obj, bool nops_only)
 			continue;
 
 		list_del(&func->node);
-
-		/* Might be called from klp_init_patch() error path. */
-		if (func->kobj_added) {
-			kobject_put(&func->kobj);
-		} else if (func->nop) {
-			klp_free_func_nop(func);
-		}
+		kobject_put(&func->kobj);
 	}
 }
 
@@ -624,13 +621,7 @@ static void __klp_free_objects(struct klp_patch *patch, bool nops_only)
 			continue;
 
 		list_del(&obj->node);
-
-		/* Might be called from klp_init_patch() error path. */
-		if (obj->kobj_added) {
-			kobject_put(&obj->kobj);
-		} else if (obj->dynamic) {
-			klp_free_object_dynamic(obj);
-		}
+		kobject_put(&obj->kobj);
 	}
 }
 
@@ -675,10 +666,8 @@ static void klp_free_patch_finish(struct klp_patch *patch)
 	 * this is called when the patch gets disabled and it
 	 * cannot get enabled again.
 	 */
-	if (patch->kobj_added) {
-		kobject_put(&patch->kobj);
-		wait_for_completion(&patch->finish);
-	}
+	kobject_put(&patch->kobj);
+	wait_for_completion(&patch->finish);
 
 	/* Put the module after the last access to struct klp_patch. */
 	if (!patch->forced)
@@ -700,8 +689,6 @@ static void klp_free_patch_work_fn(struct work_struct *work)
 
 static int klp_init_func(struct klp_object *obj, struct klp_func *func)
 {
-	int ret;
-
 	if (!func->old_name)
 		return -EINVAL;
 
@@ -724,13 +711,9 @@ static int klp_init_func(struct klp_object *obj, struct klp_func *func)
 	 * object. If the user selects 0 for old_sympos, then 1 will be used
 	 * since a unique symbol will be the first occurrence.
 	 */
-	ret = kobject_init_and_add(&func->kobj, &klp_ktype_func,
-				   &obj->kobj, "%s,%lu", func->old_name,
-				   func->old_sympos ? func->old_sympos : 1);
-	if (!ret)
-		func->kobj_added = true;
-
-	return ret;
+	return kobject_add(&func->kobj, &obj->kobj, "%s,%lu",
+			   func->old_name,
+			   func->old_sympos ? func->old_sympos : 1);
 }
 
 /* Arches may override this to finish any remaining arch-specific tasks */
@@ -801,11 +784,9 @@ static int klp_init_object(struct klp_patch *patch, struct klp_object *obj)
 	klp_find_object_module(obj);
 
 	name = klp_is_module(obj) ? obj->name : "vmlinux";
-	ret = kobject_init_and_add(&obj->kobj, &klp_ktype_object,
-				   &patch->kobj, "%s", name);
+	ret = kobject_add(&obj->kobj, &patch->kobj, "%s", name);
 	if (ret)
 		return ret;
-	obj->kobj_added = true;
 
 	klp_for_each_func(obj, func) {
 		ret = klp_init_func(obj, func);
@@ -819,6 +800,21 @@ static int klp_init_object(struct klp_patch *patch, struct klp_object *obj)
 	return ret;
 }
 
+static void klp_init_func_early(struct klp_object *obj,
+				struct klp_func *func)
+{
+	kobject_init(&func->kobj, &klp_ktype_func);
+	list_add_tail(&func->node, &obj->func_list);
+}
+
+static void klp_init_object_early(struct klp_patch *patch,
+				  struct klp_object *obj)
+{
+	INIT_LIST_HEAD(&obj->func_list);
+	kobject_init(&obj->kobj, &klp_ktype_object);
+	list_add_tail(&obj->node, &patch->obj_list);
+}
+
 static int klp_init_patch_early(struct klp_patch *patch)
 {
 	struct klp_object *obj;
@@ -829,7 +825,7 @@ static int klp_init_patch_early(struct klp_patch *patch)
 
 	INIT_LIST_HEAD(&patch->list);
 	INIT_LIST_HEAD(&patch->obj_list);
-	patch->kobj_added = false;
+	kobject_init(&patch->kobj, &klp_ktype_patch);
 	patch->enabled = false;
 	patch->forced = false;
 	INIT_WORK(&patch->free_work, klp_free_patch_work_fn);
@@ -839,13 +835,10 @@ static int klp_init_patch_early(struct klp_patch *patch)
 		if (!obj->funcs)
 			return -EINVAL;
 
-		INIT_LIST_HEAD(&obj->func_list);
-		obj->kobj_added = false;
-		list_add_tail(&obj->node, &patch->obj_list);
+		klp_init_object_early(patch, obj);
 
 		klp_for_each_func_static(obj, func) {
-			func->kobj_added = false;
-			list_add_tail(&func->node, &obj->func_list);
+			klp_init_func_early(obj, func);
 		}
 	}
 
@@ -860,11 +853,9 @@ static int klp_init_patch(struct klp_patch *patch)
 	struct klp_object *obj;
 	int ret;
 
-	ret = kobject_init_and_add(&patch->kobj, &klp_ktype_patch,
-				   klp_root_kobj, "%s", patch->mod->name);
+	ret = kobject_add(&patch->kobj, klp_root_kobj, "%s", patch->mod->name);
 	if (ret)
 		return ret;
-	patch->kobj_added = true;
 
 	if (patch->replace) {
 		ret = klp_add_nops(patch);
@@ -926,9 +917,6 @@ static int __klp_enable_patch(struct klp_patch *patch)
 	if (WARN_ON(patch->enabled))
 		return -EINVAL;
 
-	if (!patch->kobj_added)
-		return -EINVAL;
-
 	pr_notice("enabling patch '%s'\n", patch->mod->name);
 
 	klp_init_transition(patch, KLP_PATCHED);
@@ -1003,11 +991,10 @@ int klp_enable_patch(struct klp_patch *patch)
 		return -ENODEV;
 
 	if (!klp_have_reliable_stack()) {
-		pr_err("This architecture doesn't have support for the livepatch consistency model.\n");
-		return -EOPNOTSUPP;
+		pr_warn("This architecture doesn't have support for the livepatch consistency model.\n");
+		pr_warn("The livepatch transition may never complete.\n");
 	}
 
-
 	mutex_lock(&klp_mutex);
 
 	ret = klp_init_patch_early(patch);

tools/testing/selftests/livepatch/Makefile

 # SPDX-License-Identifier: GPL-2.0
 
-TEST_GEN_PROGS := \
+TEST_PROGS_EXTENDED := functions.sh
+TEST_PROGS := \
 	test-livepatch.sh \
 	test-callbacks.sh \
 	test-shadow-vars.sh