1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * core.c - Kernel Live Patching Core
25 #include "patch.h"
31  * accesses to klp-related variables and structures must have mutex protection,
34  * - klp_ftrace_handler()
35  * - klp_update_patch_state()
36  * - __klp_sched_try_switch()
51 	return obj->name;  in klp_is_module()
54 /* sets obj->mod if object is not vmlinux and module is found */
68 	mod = find_module(obj->name);  in klp_find_object_module()
71 	 * Note that the patch might still be needed before klp_module_going()  in klp_find_object_module()
73 	 * until mod->exit() finishes. This is especially important for  in klp_find_object_module()
76 	if (mod && mod->klp_alive)  in klp_find_object_module()
77 		obj->mod = mod;  in klp_find_object_module()
95 		if ((strcmp(old_func->old_name, func->old_name) == 0) &&  in klp_find_func()
96 		    ((old_func->old_sympos == func->old_sympos) ||  in klp_find_func()
97 		     (old_func->old_sympos == 0 && func->old_sympos == 1) ||  in klp_find_func()
98 		     (old_func->old_sympos == 1 && func->old_sympos == 0))) {  in klp_find_func()
106 static struct klp_object *klp_find_object(struct klp_patch *patch,  in klp_find_object()  argument
111 	klp_for_each_object(patch, obj) {  in klp_find_object()
114 			    strcmp(old_obj->name, obj->name) == 0) {  in klp_find_object()
136 	args->addr = addr;  in klp_match_callback()
137 	args->count++;  in klp_match_callback()
141 	 * or the position is not defined for a non-unique symbol.  in klp_match_callback()
143 	if ((args->pos && (args->count == args->pos)) ||  in klp_match_callback()
144 	    (!args->pos && (args->count > 1)))  in klp_match_callback()
154 	if (strcmp(args->name, name))  in klp_find_callback()
176 	 * Ensure an address was found. If sympos is 0, ensure symbol is unique;  in klp_find_object_symbol()
193 	return -EINVAL;  in klp_find_object_symbol()
211 	 * call are hard-coded and correspond to MODULE_NAME_LEN and  in klp_resolve_symbols()
221 	relas = (Elf_Rela *) relasec->sh_addr;  in klp_resolve_symbols()
223 	for (i = 0; i < relasec->sh_size / sizeof(Elf_Rela); i++) {  in klp_resolve_symbols()
225 		if (sym->st_shndx != SHN_LIVEPATCH) {  in klp_resolve_symbols()
227 			       strtab + sym->st_name, symndx, i);  in klp_resolve_symbols()
228 			return -EINVAL;  in klp_resolve_symbols()
232 		cnt = sscanf(strtab + sym->st_name,  in klp_resolve_symbols()
237 			       strtab + sym->st_name);  in klp_resolve_symbols()
238 			return -EINVAL;  in klp_resolve_symbols()
244 		 * Prevent module-specific KLP rela sections from referencing  in klp_resolve_symbols()
250 …pr_err("invalid access to vmlinux symbol '%s' from module-specific livepatch relocation section\n",  in klp_resolve_symbols()
252 			return -EINVAL;  in klp_resolve_symbols()
261 		sym->st_value = addr;  in klp_resolve_symbols()
276  * At a high-level, there are two types of klp relocation sections: those which
281  *    write vmlinux-specific klp relocations (.klp.rela.vmlinux.* sections).
288  * 2) When a to-be-patched module loads -- or is already loaded when a
289  *    corresponding klp module loads -- klp code calls this function to write
290  *    module-specific klp relocations (.klp.rela.{module}.* sections).  These
292  *    reference symbols which live in the to-be-patched module or one of its
295  *    the to-be-patched module to be loaded and patched sometime *after* the
312 	cnt = sscanf(shstrtab + sec->sh_name, KLP_RELOC_SEC_PREFIX "%55[^.]",  in klp_write_section_relocs()
316 		       shstrtab + sec->sh_name);  in klp_write_section_relocs()
317 		return -EINVAL;  in klp_write_section_relocs()
349  * /sys/kernel/livepatch/<patch>
350  * /sys/kernel/livepatch/<patch>/enabled
351  * /sys/kernel/livepatch/<patch>/transition
352  * /sys/kernel/livepatch/<patch>/force
353  * /sys/kernel/livepatch/<patch>/replace
354  * /sys/kernel/livepatch/<patch>/stack_order
355  * /sys/kernel/livepatch/<patch>/<object>
356  * /sys/kernel/livepatch/<patch>/<object>/patched
357  * /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
359 static int __klp_disable_patch(struct klp_patch *patch);
364 	struct klp_patch *patch;  in enabled_store()  local
372 	patch = container_of(kobj, struct klp_patch, kobj);  in enabled_store()
376 	if (patch->enabled == enabled) {  in enabled_store()
378 		ret = -EINVAL;  in enabled_store()
387 	 * Do not allow to re-enable a disabled patch.  in enabled_store()
389 	if (patch == klp_transition_patch)  in enabled_store()
392 		ret = __klp_disable_patch(patch);  in enabled_store()
394 		ret = -EINVAL;  in enabled_store()
407 	struct klp_patch *patch;  in enabled_show()  local
409 	patch = container_of(kobj, struct klp_patch, kobj);  in enabled_show()
410 	return sysfs_emit(buf, "%d\n", patch->enabled);  in enabled_show()
416 	struct klp_patch *patch;  in transition_show()  local
418 	patch = container_of(kobj, struct klp_patch, kobj);  in transition_show()
419 	return sysfs_emit(buf, "%d\n", patch == klp_transition_patch);  in transition_show()
425 	struct klp_patch *patch;  in force_store()  local
438 	patch = container_of(kobj, struct klp_patch, kobj);  in force_store()
439 	if (patch != klp_transition_patch) {  in force_store()
441 		return -EINVAL;  in force_store()
454 	struct klp_patch *patch;  in replace_show()  local
456 	patch = container_of(kobj, struct klp_patch, kobj);  in replace_show()
457 	return sysfs_emit(buf, "%d\n", patch->replace);  in replace_show()
463 	struct klp_patch *patch, *this_patch;  in stack_order_show()  local
470 	klp_for_each_patch(patch) {  in stack_order_show()
472 		if (patch == this_patch)  in stack_order_show()
502 	return sysfs_emit(buf, "%d\n", obj->patched);  in patched_show()
514 	kfree(obj->name);  in klp_free_object_dynamic()
520 static void klp_init_object_early(struct klp_patch *patch,
524 						   struct klp_patch *patch)  in klp_alloc_object_dynamic()  argument
533 		obj->name = kstrdup(name, GFP_KERNEL);  in klp_alloc_object_dynamic()
534 		if (!obj->name) {  in klp_alloc_object_dynamic()
540 	klp_init_object_early(patch, obj);  in klp_alloc_object_dynamic()
541 	obj->dynamic = true;  in klp_alloc_object_dynamic()
548 	kfree(func->old_name);  in klp_free_func_nop()
561 	if (old_func->old_name) {  in klp_alloc_func_nop()
562 		func->old_name = kstrdup(old_func->old_name, GFP_KERNEL);  in klp_alloc_func_nop()
563 		if (!func->old_name) {  in klp_alloc_func_nop()
571 	 * func->new_func is same as func->old_func. These addresses are  in klp_alloc_func_nop()
574 	func->old_sympos = old_func->old_sympos;  in klp_alloc_func_nop()
575 	func->nop = true;  in klp_alloc_func_nop()
580 static int klp_add_object_nops(struct klp_patch *patch,  in klp_add_object_nops()  argument
586 	obj = klp_find_object(patch, old_obj);  in klp_add_object_nops()
589 		obj = klp_alloc_object_dynamic(old_obj->name, patch);  in klp_add_object_nops()
591 			return -ENOMEM;  in klp_add_object_nops()
601 			return -ENOMEM;  in klp_add_object_nops()
615 static int klp_add_nops(struct klp_patch *patch)  in klp_add_nops()  argument
624 			err = klp_add_object_nops(patch, old_obj);  in klp_add_nops()
635 	struct klp_patch *patch;  in klp_kobj_release_patch()  local
637 	patch = container_of(kobj, struct klp_patch, kobj);  in klp_kobj_release_patch()
638 	complete(&patch->finish);  in klp_kobj_release_patch()
653 	if (obj->dynamic)  in klp_kobj_release_object()
669 	if (func->nop)  in klp_kobj_release_func()
683 		if (nops_only && !func->nop)  in __klp_free_funcs()
686 		list_del(&func->node);  in __klp_free_funcs()
687 		kobject_put(&func->kobj);  in __klp_free_funcs()
696 	obj->mod = NULL;  in klp_free_object_loaded()
699 		func->old_func = NULL;  in klp_free_object_loaded()
701 		if (func->nop)  in klp_free_object_loaded()
702 			func->new_func = NULL;  in klp_free_object_loaded()
706 static void __klp_free_objects(struct klp_patch *patch, bool nops_only)  in __klp_free_objects()  argument
710 	klp_for_each_object_safe(patch, obj, tmp_obj) {  in __klp_free_objects()
713 		if (nops_only && !obj->dynamic)  in __klp_free_objects()
716 		list_del(&obj->node);  in __klp_free_objects()
717 		kobject_put(&obj->kobj);  in __klp_free_objects()
721 static void klp_free_objects(struct klp_patch *patch)  in klp_free_objects()  argument
723 	__klp_free_objects(patch, false);  in klp_free_objects()
726 static void klp_free_objects_dynamic(struct klp_patch *patch)  in klp_free_objects_dynamic()  argument
728 	__klp_free_objects(patch, true);  in klp_free_objects_dynamic()
738 static void klp_free_patch_start(struct klp_patch *patch)  in klp_free_patch_start()  argument
740 	if (!list_empty(&patch->list))  in klp_free_patch_start()
741 		list_del(&patch->list);  in klp_free_patch_start()
743 	klp_free_objects(patch);  in klp_free_patch_start()
751  * the last function accessing the livepatch structures when the patch
754 static void klp_free_patch_finish(struct klp_patch *patch)  in klp_free_patch_finish()  argument
759 	 * this is called when the patch gets disabled and it  in klp_free_patch_finish()
762 	kobject_put(&patch->kobj);  in klp_free_patch_finish()
763 	wait_for_completion(&patch->finish);  in klp_free_patch_finish()
766 	if (!patch->forced)  in klp_free_patch_finish()
767 		module_put(patch->mod);  in klp_free_patch_finish()
771  * The livepatch might be freed from sysfs interface created by the patch.
777 	struct klp_patch *patch =  in klp_free_patch_work_fn()  local
780 	klp_free_patch_finish(patch);  in klp_free_patch_work_fn()
783 void klp_free_patch_async(struct klp_patch *patch)  in klp_free_patch_async()  argument
785 	klp_free_patch_start(patch);  in klp_free_patch_async()
786 	schedule_work(&patch->free_work);  in klp_free_patch_async()
802 	if (!func->old_name)  in klp_init_func()
803 		return -EINVAL;  in klp_init_func()
806 	 * NOPs get the address later. The patched module must be loaded,  in klp_init_func()
809 	if (!func->new_func && !func->nop)  in klp_init_func()
810 		return -EINVAL;  in klp_init_func()
812 	if (strlen(func->old_name) >= KSYM_NAME_LEN)  in klp_init_func()
813 		return -EINVAL;  in klp_init_func()
815 	INIT_LIST_HEAD(&func->stack_node);  in klp_init_func()
816 	func->patched = false;  in klp_init_func()
817 	func->transition = false;  in klp_init_func()
824 	return kobject_add(&func->kobj, &obj->kobj, "%s,%lu",  in klp_init_func()
825 			   func->old_name,  in klp_init_func()
826 			   func->old_sympos ? func->old_sympos : 1);  in klp_init_func()
829 static int klp_write_object_relocs(struct klp_patch *patch,  in klp_write_object_relocs()  argument
834 	struct klp_modinfo *info = patch->mod->klp_info;  in klp_write_object_relocs()
836 	for (i = 1; i < info->hdr.e_shnum; i++) {  in klp_write_object_relocs()
837 		Elf_Shdr *sec = info->sechdrs + i;  in klp_write_object_relocs()
839 		if (!(sec->sh_flags & SHF_RELA_LIVEPATCH))  in klp_write_object_relocs()
842 		ret = klp_write_section_relocs(patch->mod, info->sechdrs,  in klp_write_object_relocs()
843 					       info->secstrings,  in klp_write_object_relocs()
844 					       patch->mod->core_kallsyms.strtab,  in klp_write_object_relocs()
845 					       info->symndx, i, obj->name, apply);  in klp_write_object_relocs()
853 static int klp_apply_object_relocs(struct klp_patch *patch,  in klp_apply_object_relocs()  argument
856 	return klp_write_object_relocs(patch, obj, true);  in klp_apply_object_relocs()
859 static void klp_clear_object_relocs(struct klp_patch *patch,  in klp_clear_object_relocs()  argument
862 	klp_write_object_relocs(patch, obj, false);  in klp_clear_object_relocs()
866 static int klp_init_object_loaded(struct klp_patch *patch,  in klp_init_object_loaded()  argument
874 		 * Only write module-specific relocations here  in klp_init_object_loaded()
875 		 * (.klp.rela.{module}.*).  vmlinux-specific relocations were  in klp_init_object_loaded()
879 		ret = klp_apply_object_relocs(patch, obj);  in klp_init_object_loaded()
885 		ret = klp_find_object_symbol(obj->name, func->old_name,  in klp_init_object_loaded()
886 					     func->old_sympos,  in klp_init_object_loaded()
887 					     (unsigned long *)&func->old_func);  in klp_init_object_loaded()
891 		ret = kallsyms_lookup_size_offset((unsigned long)func->old_func,  in klp_init_object_loaded()
892 						  &func->old_size, NULL);  in klp_init_object_loaded()
895 			       func->old_name);  in klp_init_object_loaded()
896 			return -ENOENT;  in klp_init_object_loaded()
899 		if (func->nop)  in klp_init_object_loaded()
900 			func->new_func = func->old_func;  in klp_init_object_loaded()
902 		ret = kallsyms_lookup_size_offset((unsigned long)func->new_func,  in klp_init_object_loaded()
903 						  &func->new_size, NULL);  in klp_init_object_loaded()
906 			       func->old_name);  in klp_init_object_loaded()
907 			return -ENOENT;  in klp_init_object_loaded()
914 static int klp_init_object(struct klp_patch *patch, struct klp_object *obj)  in klp_init_object()  argument
920 	if (klp_is_module(obj) && strlen(obj->name) >= MODULE_NAME_LEN)  in klp_init_object()
921 		return -EINVAL;  in klp_init_object()
923 	obj->patched = false;  in klp_init_object()
924 	obj->mod = NULL;  in klp_init_object()
928 	name = klp_is_module(obj) ? obj->name : "vmlinux";  in klp_init_object()
929 	ret = kobject_add(&obj->kobj, &patch->kobj, "%s", name);  in klp_init_object()
940 		ret = klp_init_object_loaded(patch, obj);  in klp_init_object()
948 	kobject_init(&func->kobj, &klp_ktype_func);  in klp_init_func_early()
949 	list_add_tail(&func->node, &obj->func_list);  in klp_init_func_early()
952 static void klp_init_object_early(struct klp_patch *patch,  in klp_init_object_early()  argument
955 	INIT_LIST_HEAD(&obj->func_list);  in klp_init_object_early()
956 	kobject_init(&obj->kobj, &klp_ktype_object);  in klp_init_object_early()
957 	list_add_tail(&obj->node, &patch->obj_list);  in klp_init_object_early()
960 static void klp_init_patch_early(struct klp_patch *patch)  in klp_init_patch_early()  argument
965 	INIT_LIST_HEAD(&patch->list);  in klp_init_patch_early()
966 	INIT_LIST_HEAD(&patch->obj_list);  in klp_init_patch_early()
967 	kobject_init(&patch->kobj, &klp_ktype_patch);  in klp_init_patch_early()
968 	patch->enabled = false;  in klp_init_patch_early()
969 	patch->forced = false;  in klp_init_patch_early()
970 	INIT_WORK(&patch->free_work, klp_free_patch_work_fn);  in klp_init_patch_early()
971 	init_completion(&patch->finish);  in klp_init_patch_early()
973 	klp_for_each_object_static(patch, obj) {  in klp_init_patch_early()
974 		klp_init_object_early(patch, obj);  in klp_init_patch_early()
982 static int klp_init_patch(struct klp_patch *patch)  in klp_init_patch()  argument
987 	ret = kobject_add(&patch->kobj, klp_root_kobj, "%s", patch->mod->name);  in klp_init_patch()
991 	if (patch->replace) {  in klp_init_patch()
992 		ret = klp_add_nops(patch);  in klp_init_patch()
997 	klp_for_each_object(patch, obj) {  in klp_init_patch()
998 		ret = klp_init_object(patch, obj);  in klp_init_patch()
1003 	list_add_tail(&patch->list, &klp_patches);  in klp_init_patch()
1008 static int __klp_disable_patch(struct klp_patch *patch)  in __klp_disable_patch()  argument
1012 	if (WARN_ON(!patch->enabled))  in __klp_disable_patch()
1013 		return -EINVAL;  in __klp_disable_patch()
1016 		return -EBUSY;  in __klp_disable_patch()
1018 	klp_init_transition(patch, KLP_TRANSITION_UNPATCHED);  in __klp_disable_patch()
1020 	klp_for_each_object(patch, obj)  in __klp_disable_patch()
1021 		if (obj->patched)  in __klp_disable_patch()
1025 	 * Enforce the order of the func->transition writes in  in __klp_disable_patch()
1029 	 * this ensures the handler sees that func->transition is set.  in __klp_disable_patch()
1034 	patch->enabled = false;  in __klp_disable_patch()
1040 static int __klp_enable_patch(struct klp_patch *patch)  in __klp_enable_patch()  argument
1046 		return -EBUSY;  in __klp_enable_patch()
1048 	if (WARN_ON(patch->enabled))  in __klp_enable_patch()
1049 		return -EINVAL;  in __klp_enable_patch()
1051 	pr_notice("enabling patch '%s'\n", patch->mod->name);  in __klp_enable_patch()
1053 	klp_init_transition(patch, KLP_TRANSITION_PATCHED);  in __klp_enable_patch()
1056 	 * Enforce the order of the func->transition writes in  in __klp_enable_patch()
1057 	 * klp_init_transition() and the ops->func_stack writes in  in __klp_enable_patch()
1059 	 * func->transition updates before the handler is registered and the  in __klp_enable_patch()
1064 	klp_for_each_object(patch, obj) {  in __klp_enable_patch()
1070 			pr_warn("pre-patch callback failed for object '%s'\n",  in __klp_enable_patch()
1071 				klp_is_module(obj) ? obj->name : "vmlinux");  in __klp_enable_patch()
1077 			pr_warn("failed to patch object '%s'\n",  in __klp_enable_patch()
1078 				klp_is_module(obj) ? obj->name : "vmlinux");  in __klp_enable_patch()
1084 	patch->enabled = true;  in __klp_enable_patch()
1089 	pr_warn("failed to enable patch '%s'\n", patch->mod->name);  in __klp_enable_patch()
1096  * klp_enable_patch() - enable the livepatch
1097  * @patch:	patch to be enabled
1099  * Initializes the data structure associated with the patch, creates the sysfs
1108 int klp_enable_patch(struct klp_patch *patch)  in klp_enable_patch()  argument
1113 	if (!patch || !patch->mod || !patch->objs)  in klp_enable_patch()
1114 		return -EINVAL;  in klp_enable_patch()
1116 	klp_for_each_object_static(patch, obj) {  in klp_enable_patch()
1117 		if (!obj->funcs)  in klp_enable_patch()
1118 			return -EINVAL;  in klp_enable_patch()
1122 	if (!is_livepatch_module(patch->mod)) {  in klp_enable_patch()
1124 		       patch->mod->name);  in klp_enable_patch()
1125 		return -EINVAL;  in klp_enable_patch()
1129 		return -ENODEV;  in klp_enable_patch()
1138 	if (!klp_is_patch_compatible(patch)) {  in klp_enable_patch()
1139 		pr_err("Livepatch patch (%s) is not compatible with the already installed livepatches.\n",  in klp_enable_patch()
1140 			patch->mod->name);  in klp_enable_patch()
1142 		return -EINVAL;  in klp_enable_patch()
1145 	if (!try_module_get(patch->mod)) {  in klp_enable_patch()
1147 		return -ENODEV;  in klp_enable_patch()
1150 	klp_init_patch_early(patch);  in klp_enable_patch()
1152 	ret = klp_init_patch(patch);  in klp_enable_patch()
1156 	ret = __klp_enable_patch(patch);  in klp_enable_patch()
1165 	klp_free_patch_start(patch);  in klp_enable_patch()
1169 	klp_free_patch_finish(patch);  in klp_enable_patch()
1185  * klp_ftrace_handler() might still see the replaced patch on the stack.
1188  * this is handled transparently by patch->module_put.
1198 		old_patch->enabled = false;  in klp_unpatch_replaced_patches()
1210  * will see a valid ops->func_stack entry thanks to RCU.
1213  * in ops->func_stack. Therefore unregister_ftrace_function() is called.
1233 	struct klp_patch *patch;  in klp_cleanup_module_patches_limited()  local
1236 	klp_for_each_patch(patch) {  in klp_cleanup_module_patches_limited()
1237 		if (patch == limit)  in klp_cleanup_module_patches_limited()
1240 		klp_for_each_object(patch, obj) {  in klp_cleanup_module_patches_limited()
1241 			if (!klp_is_module(obj) || strcmp(obj->name, mod->name))  in klp_cleanup_module_patches_limited()
1244 			if (patch != klp_transition_patch)  in klp_cleanup_module_patches_limited()
1247 			pr_notice("reverting patch '%s' on unloading module '%s'\n",  in klp_cleanup_module_patches_limited()
1248 				  patch->mod->name, obj->mod->name);  in klp_cleanup_module_patches_limited()
1252 			klp_clear_object_relocs(patch, obj);  in klp_cleanup_module_patches_limited()
1262 	struct klp_patch *patch;  in klp_module_coming()  local
1265 	if (WARN_ON(mod->state != MODULE_STATE_COMING))  in klp_module_coming()
1266 		return -EINVAL;  in klp_module_coming()
1268 	if (!strcmp(mod->name, "vmlinux")) {  in klp_module_coming()
1270 		return -EINVAL;  in klp_module_coming()
1277 	 * get patched by a new patch.  in klp_module_coming()
1279 	mod->klp_alive = true;  in klp_module_coming()
1281 	klp_for_each_patch(patch) {  in klp_module_coming()
1282 		klp_for_each_object(patch, obj) {  in klp_module_coming()
1283 			if (!klp_is_module(obj) || strcmp(obj->name, mod->name))  in klp_module_coming()
1286 			obj->mod = mod;  in klp_module_coming()
1288 			ret = klp_init_object_loaded(patch, obj);  in klp_module_coming()
1290 				pr_warn("failed to initialize patch '%s' for module '%s' (%d)\n",  in klp_module_coming()
1291 					patch->mod->name, obj->mod->name, ret);  in klp_module_coming()
1295 			pr_notice("applying patch '%s' to loading module '%s'\n",  in klp_module_coming()
1296 				  patch->mod->name, obj->mod->name);  in klp_module_coming()
1300 				pr_warn("pre-patch callback failed for object '%s'\n",  in klp_module_coming()
1301 					obj->name);  in klp_module_coming()
1307 				pr_warn("failed to apply patch '%s' to module '%s' (%d)\n",  in klp_module_coming()
1308 					patch->mod->name, obj->mod->name, ret);  in klp_module_coming()
1314 			if (patch != klp_transition_patch)  in klp_module_coming()
1327 	 * If a patch is unsuccessfully applied, return  in klp_module_coming()
1330 	pr_warn("patch '%s' failed for module '%s', refusing to load module '%s'\n",  in klp_module_coming()
1331 		patch->mod->name, obj->mod->name, obj->mod->name);  in klp_module_coming()
1332 	mod->klp_alive = false;  in klp_module_coming()
1333 	obj->mod = NULL;  in klp_module_coming()
1334 	klp_cleanup_module_patches_limited(mod, patch);  in klp_module_coming()
1342 	if (WARN_ON(mod->state != MODULE_STATE_GOING &&  in klp_module_going()
1343 		    mod->state != MODULE_STATE_COMING))  in klp_module_going()
1350 	 * get patched by a new patch.  in klp_module_going()
1352 	mod->klp_alive = false;  in klp_module_going()
1362 	struct klp_modinfo *info = mod->klp_info;  in klp_find_section_by_name()
1364 	for (int i = 1; i < info->hdr.e_shnum; i++) {  in klp_find_section_by_name()
1365 		Elf_Shdr *shdr = &info->sechdrs[i];  in klp_find_section_by_name()
1367 		if (!strcmp(info->secstrings + shdr->sh_name, name)) {  in klp_find_section_by_name()
1368 			*sec_size = shdr->sh_size;  in klp_find_section_by_name()
1369 			return (void *)shdr->sh_addr;  in klp_find_section_by_name()
1382 		return -ENOMEM;  in klp_init()