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Commit 4d141ab3 authored by Petr Mladek's avatar Petr Mladek Committed by Jiri Kosina
Browse files

livepatch: Remove custom kobject state handling 



kobject_init() always succeeds and sets the reference count to 1.
It allows to always free the structures via kobject_put() and
the related release callback.

Note that the custom kobject state handling was used only
because we did not know that kobject_put() can and actually
should get called even when kobject_init_and_add() fails.

The patch should not change the existing behavior.

Suggested-by: default avatar"Tobin C. Harding" <tobin@kernel.org>
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
Reviewed-by: default avatarKamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: default avatarJoe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 31adf230

include/linux/livepatch.h

+0 −3
Original line number Diff line number Diff line
@@ -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

+17 −39
Original line number Diff line number Diff line
@@ -426,6 +426,9 @@ static void klp_free_object_dynamic(struct klp_object *obj) 
	kfree(obj);

}



static struct kobj_type klp_ktype_object;

static struct kobj_type klp_ktype_func;



static struct klp_object *klp_alloc_object_dynamic(const char *name)

{

	struct klp_object *obj;
@@ -443,6 +446,7 @@ static struct klp_object *klp_alloc_object_dynamic(const char *name) 
	}



	INIT_LIST_HEAD(&obj->func_list);

	kobject_init(&obj->kobj, &klp_ktype_object);

	obj->dynamic = true;



	return obj;
@@ -471,6 +475,7 @@ static struct klp_func *klp_alloc_func_nop(struct klp_func *old_func, 
		}

	}



	kobject_init(&func->kobj, &klp_ktype_func);

	/*

	 * func->new_func is same as func->old_func. These addresses are

	 * set when the object is loaded, see klp_init_object_loaded().
@@ -588,13 +593,7 @@ 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);

		}

	}

}
@@ -624,13 +623,7 @@ 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);

		}

	}

}
@@ -675,10 +668,8 @@ 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);

	}



	/* Put the module after the last access to struct klp_patch. */

	if (!patch->forced)
@@ -700,8 +691,6 @@ 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 +713,9 @@ 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,

	return kobject_add(&func->kobj, &obj->kobj, "%s,%lu",

			   func->old_name,

			   func->old_sympos ? func->old_sympos : 1);

	if (!ret)

		func->kobj_added = true;



	return ret;

}



/* Arches may override this to finish any remaining arch-specific tasks */
@@ -801,11 +786,9 @@ 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);
@@ -829,7 +812,7 @@ 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);
@@ -840,11 +823,11 @@ static int klp_init_patch_early(struct klp_patch *patch) 
			return -EINVAL;



		INIT_LIST_HEAD(&obj->func_list);

		obj->kobj_added = false;

		kobject_init(&obj->kobj, &klp_ktype_object);

		list_add_tail(&obj->node, &patch->obj_list);



		klp_for_each_func_static(obj, func) {

			func->kobj_added = false;

			kobject_init(&func->kobj, &klp_ktype_func);

			list_add_tail(&func->node, &obj->func_list);

		}

	}
@@ -860,11 +843,9 @@ 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 +907,6 @@ 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);