From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 369FAC63777 for ; Mon, 30 Nov 2020 21:19:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA5B62076A for ; Mon, 30 Nov 2020 21:19:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388542AbgK3VTe (ORCPT ); Mon, 30 Nov 2020 16:19:34 -0500 Received: from mail.kernel.org ([198.145.29.99]:39726 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387645AbgK3VTd (ORCPT ); Mon, 30 Nov 2020 16:19:33 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0A82C2076A; Mon, 30 Nov 2020 21:18:51 +0000 (UTC) Date: Mon, 30 Nov 2020 16:18:50 -0500 From: Steven Rostedt To: Masami Hiramatsu Cc: Wang ShaoBo , , , , , , Subject: Re: [PATCH] kretprobe: avoid re-registration of the same kretprobe earlier Message-ID: <20201130161850.34bcfc8a@gandalf.local.home> In-Reply-To: <20201124115719.11799-1-bobo.shaobowang@huawei.com> References: <20201124115719.11799-1-bobo.shaobowang@huawei.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Masami, Can you review this patch, and also, should this go to -rc and stable? -- Steve On Tue, 24 Nov 2020 19:57:19 +0800 Wang ShaoBo wrote: > Our system encountered a re-init error when re-registering same kretprobe, > where the kretprobe_instance in rp->free_instances is illegally accessed > after re-init. > > Implementation to avoid re-registration has been introduced for kprobe > before, but lags for register_kretprobe(). We must check if kprobe has > been re-registered before re-initializing kretprobe, otherwise it will > destroy the data struct of kretprobe registered, which can lead to memory > leak, system crash, also some unexpected behaviors. > > we use check_kprobe_rereg() to check if kprobe has been re-registered > before calling register_kretprobe(), for giving a warning message and > terminate registration process. > > Signed-off-by: Wang ShaoBo > Signed-off-by: Cheng Jian > --- > kernel/kprobes.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index 41fdbb7953c6..7f54a70136f3 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -2117,6 +2117,14 @@ int register_kretprobe(struct kretprobe *rp) > } > } > > + /* > + * Return error if it's being re-registered, > + * also give a warning message to the developer. > + */ > + ret = check_kprobe_rereg(&rp->kp); > + if (WARN_ON(ret)) > + return ret; > + > rp->kp.pre_handler = pre_handler_kretprobe; > rp->kp.post_handler = NULL; > rp->kp.fault_handler = NULL;