From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751831AbdJBP4x (ORCPT ); Mon, 2 Oct 2017 11:56:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40948 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751380AbdJBP4w (ORCPT ); Mon, 2 Oct 2017 11:56:52 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com DE6C0C04AC64 Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=joe.lawrence@redhat.com From: Joe Lawrence To: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Josh Poimboeuf , Jessica Yu , Jiri Kosina , Miroslav Benes , Petr Mladek Subject: [PATCH v2] livepatch: unpatch all klp_objects if klp_module_coming fails Date: Mon, 2 Oct 2017 11:56:48 -0400 Message-Id: <1506959808-23838-1-git-send-email-joe.lawrence@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Mon, 02 Oct 2017 15:56:52 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When an incoming module is considered for livepatching by klp_module_coming(), it iterates over multiple patches and multiple kernel objects in this order: list_for_each_entry(patch, &klp_patches, list) { klp_for_each_object(patch, obj) { which means that if one of the kernel objects fails to patch, klp_module_coming()'s error path needs to unpatch and cleanup any kernel objects that were already patched by a previous patch. Reported-by: Miroslav Benes Suggested-by: Petr Mladek Signed-off-by: Joe Lawrence --- v2: - cleanup comment describing the new function - s/klp_cleanup_module_objects_limited/klp_cleanup_module_patches_limited - added a suggested-by tag for Petr since he suggested both code and commentary :) kernel/livepatch/core.c | 60 ++++++++++++++++++++++++++++++------------------- 1 file changed, 37 insertions(+), 23 deletions(-) diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index b9628e43c78f..bf8c8fd72589 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -830,6 +830,41 @@ int klp_register_patch(struct klp_patch *patch) } EXPORT_SYMBOL_GPL(klp_register_patch); +/* + * Remove parts of patches that touch a given kernel module. The list of + * patches processed might be limited. When limit is NULL, all patches + * will be handled. + */ +static void klp_cleanup_module_patches_limited(struct module *mod, + struct klp_patch *limit) +{ + struct klp_patch *patch; + struct klp_object *obj; + + list_for_each_entry(patch, &klp_patches, list) { + if (patch == limit) + break; + + klp_for_each_object(patch, obj) { + if (!klp_is_module(obj) || strcmp(obj->name, mod->name)) + continue; + + /* + * Only unpatch the module if the patch is enabled or + * is in transition. + */ + if (patch->enabled || patch == klp_transition_patch) { + pr_notice("reverting patch '%s' on unloading module '%s'\n", + patch->mod->name, obj->mod->name); + klp_unpatch_object(obj); + } + + klp_free_object_loaded(obj); + break; + } + } +} + int klp_module_coming(struct module *mod) { int ret; @@ -894,7 +929,7 @@ int klp_module_coming(struct module *mod) pr_warn("patch '%s' failed for module '%s', refusing to load module '%s'\n", patch->mod->name, obj->mod->name, obj->mod->name); mod->klp_alive = false; - klp_free_object_loaded(obj); + klp_cleanup_module_patches_limited(mod, patch); mutex_unlock(&klp_mutex); return ret; @@ -902,9 +937,6 @@ int klp_module_coming(struct module *mod) void klp_module_going(struct module *mod) { - struct klp_patch *patch; - struct klp_object *obj; - if (WARN_ON(mod->state != MODULE_STATE_GOING && mod->state != MODULE_STATE_COMING)) return; @@ -917,25 +949,7 @@ void klp_module_going(struct module *mod) */ mod->klp_alive = false; - list_for_each_entry(patch, &klp_patches, list) { - klp_for_each_object(patch, obj) { - if (!klp_is_module(obj) || strcmp(obj->name, mod->name)) - continue; - - /* - * Only unpatch the module if the patch is enabled or - * is in transition. - */ - if (patch->enabled || patch == klp_transition_patch) { - pr_notice("reverting patch '%s' on unloading module '%s'\n", - patch->mod->name, obj->mod->name); - klp_unpatch_object(obj); - } - - klp_free_object_loaded(obj); - break; - } - } + klp_cleanup_module_patches_limited(mod, NULL); mutex_unlock(&klp_mutex); } -- 1.8.3.1