Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752459AbbEKCzD (ORCPT ); Sun, 10 May 2015 22:55:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46534 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751644AbbEKCy6 (ORCPT ); Sun, 10 May 2015 22:54:58 -0400 From: Minfei Huang To: jpoimboe@redhat.com, sjenning@redhat.com, jkosina@suse.cz, vojtech@suse.cz Cc: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, Minfei Huang Subject: [PATCH] livepatch: Prevent to enable uninitialized patch Date: Mon, 11 May 2015 10:57:46 +0800 Message-Id: <1431313066-3102-1-git-send-email-mhuang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2781 Lines: 92 From: Minfei Huang The previous patches can be applied, while the corresponding module is loaded. Now the code cannot handle correct behavior to deal with the case that the patch fail to be initialized when the module is being loaded. In general, the patch will do relocation (if necessary) and obtain/verify function address before we start to enable patch. But we can still trigger to enable the patch (disable the patch firstly, then enable it), although the patch fail to be initialized in the function klp_module_notify_coming. To fix it, we can make obj->mod to NULL, if the object fails to be initialized. Signed-off-by: Minfei Huang --- kernel/livepatch/core.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 284e269..4bbcdda 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -883,30 +883,30 @@ int klp_register_patch(struct klp_patch *patch) } EXPORT_SYMBOL_GPL(klp_register_patch); -static void klp_module_notify_coming(struct klp_patch *patch, +static int klp_module_notify_coming(struct klp_patch *patch, struct klp_object *obj) { struct module *pmod = patch->mod; struct module *mod = obj->mod; - int ret; + int ret = 0; ret = klp_init_object_loaded(patch, obj); if (ret) - goto err; + goto out; if (patch->state == KLP_DISABLED) - return; + goto out; pr_notice("applying patch '%s' to loading module '%s'\n", pmod->name, mod->name); ret = klp_enable_object(obj); - if (!ret) - return; -err: - pr_warn("failed to apply patch '%s' to module '%s' (%d)\n", - pmod->name, mod->name, ret); +out: + if (ret) + pr_warn("failed to apply patch '%s' to module '%s' (%d)\n", + pmod->name, mod->name, ret); + return ret; } static void klp_module_notify_going(struct klp_patch *patch, @@ -930,6 +930,7 @@ disabled: static int klp_module_notify(struct notifier_block *nb, unsigned long action, void *data) { + int ret = 0; struct module *mod = data; struct klp_patch *patch; struct klp_object *obj; @@ -955,7 +956,9 @@ static int klp_module_notify(struct notifier_block *nb, unsigned long action, if (action == MODULE_STATE_COMING) { obj->mod = mod; - klp_module_notify_coming(patch, obj); + ret = klp_module_notify_coming(patch, obj); + if (ret) + obj->mod = NULL; } else /* MODULE_STATE_GOING */ klp_module_notify_going(patch, obj); -- 2.2.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/