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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 A4C03C43382 for ; Wed, 26 Sep 2018 16:13:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6628121528 for ; Wed, 26 Sep 2018 16:13:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6628121528 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728780AbeIZW1T (ORCPT ); Wed, 26 Sep 2018 18:27:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:55064 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728409AbeIZW1S (ORCPT ); Wed, 26 Sep 2018 18:27:18 -0400 Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (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 AE87D21546; Wed, 26 Sep 2018 16:13:37 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.91) (envelope-from ) id 1g5CRU-0003pl-Pl; Wed, 26 Sep 2018 12:13:36 -0400 Message-Id: <20180926161336.698132369@goodmis.org> User-Agent: quilt/0.65 Date: Wed, 26 Sep 2018 12:12:30 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Srikar Dronamraju , Song Liu , Oleg Nesterov , Ravi Bangoria Subject: [for-next][PATCH 4/5] trace_uprobe/sdt: Prevent multiple reference counter for same uprobe References: <20180926161226.098070917@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ravi Bangoria We assume to have only one reference counter for one uprobe. Don't allow user to add multiple trace_uprobe entries having same inode+offset but different reference counter. Ex, # echo "p:sdt_tick/loop2 /home/ravi/tick:0x6e4(0x10036)" > uprobe_events # echo "p:sdt_tick/loop2_1 /home/ravi/tick:0x6e4(0xfffff)" >> uprobe_events bash: echo: write error: Invalid argument # dmesg trace_kprobe: Reference counter offset mismatch. There is one exception though: When user is trying to replace the old entry with the new one, we allow this if the new entry does not conflict with any other existing entries. Link: http://lkml.kernel.org/r/20180820044250.11659-4-ravi.bangoria@linux.ibm.com Acked-by: Srikar Dronamraju Reviewed-by: Song Liu Reviewed-by: Oleg Nesterov Tested-by: Song Liu Signed-off-by: Ravi Bangoria Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_uprobe.c | 37 +++++++++++++++++++++++++++++++++++-- 1 file changed, 35 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 7b85172beab6..3a7c73c40007 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -312,6 +312,35 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu) return 0; } +/* + * Uprobe with multiple reference counter is not allowed. i.e. + * If inode and offset matches, reference counter offset *must* + * match as well. Though, there is one exception: If user is + * replacing old trace_uprobe with new one(same group/event), + * then we allow same uprobe with new reference counter as far + * as the new one does not conflict with any other existing + * ones. + */ +static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new) +{ + struct trace_uprobe *tmp, *old = NULL; + struct inode *new_inode = d_real_inode(new->path.dentry); + + old = find_probe_event(trace_event_name(&new->tp.call), + new->tp.call.class->system); + + list_for_each_entry(tmp, &uprobe_list, list) { + if ((old ? old != tmp : true) && + new_inode == d_real_inode(tmp->path.dentry) && + new->offset == tmp->offset && + new->ref_ctr_offset != tmp->ref_ctr_offset) { + pr_warn("Reference counter offset mismatch."); + return ERR_PTR(-EINVAL); + } + } + return old; +} + /* Register a trace_uprobe and probe_event */ static int register_trace_uprobe(struct trace_uprobe *tu) { @@ -321,8 +350,12 @@ static int register_trace_uprobe(struct trace_uprobe *tu) mutex_lock(&uprobe_lock); /* register as an event */ - old_tu = find_probe_event(trace_event_name(&tu->tp.call), - tu->tp.call.class->system); + old_tu = find_old_trace_uprobe(tu); + if (IS_ERR(old_tu)) { + ret = PTR_ERR(old_tu); + goto end; + } + if (old_tu) { /* delete old event */ ret = unregister_trace_uprobe(old_tu); -- 2.18.0