From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=unavailable autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id AB81B7D048 for ; Wed, 20 Jun 2018 03:58:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754610AbeFTD5J (ORCPT ); Tue, 19 Jun 2018 23:57:09 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:58494 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754601AbeFTD5F (ORCPT ); Tue, 19 Jun 2018 23:57:05 -0400 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w5K3t66v061792 for ; Tue, 19 Jun 2018 23:57:05 -0400 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0b-001b2d01.pphosted.com with ESMTP id 2jqe9tt4u5-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 19 Jun 2018 23:57:05 -0400 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 20 Jun 2018 04:56:59 +0100 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w5K3uwSG30408808 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 20 Jun 2018 03:56:58 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C865BAE057; Wed, 20 Jun 2018 04:45:40 +0100 (BST) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 15DE4AE045; Wed, 20 Jun 2018 04:45:38 +0100 (BST) Received: from bangoria.in.ibm.com (unknown [9.124.31.59]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 20 Jun 2018 04:45:37 +0100 (BST) From: Ravi Bangoria To: oleg@redhat.com, srikar@linux.vnet.ibm.com, rostedt@goodmis.org, mhiramat@kernel.org Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org, alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org, linux-kernel@vger.kernel.org, corbet@lwn.net, linux-doc@vger.kernel.org, ananth@linux.vnet.ibm.com, alexis.berlemont@gmail.com, naveen.n.rao@linux.vnet.ibm.com, Ravi Bangoria Subject: [PATCH v4 6/9] trace_uprobe/sdt: Prevent multiple reference counter for same uprobe Date: Wed, 20 Jun 2018 09:26:26 +0530 X-Mailer: git-send-email 2.14.4 In-Reply-To: <20180620035629.7844-1-ravi.bangoria@linux.ibm.com> References: <20180620035629.7844-1-ravi.bangoria@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18062003-4275-0000-0000-0000028FB0A7 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18062003-4276-0000-0000-00003796F6C9 Message-Id: <20180620035629.7844-7-ravi.bangoria@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-06-20_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1805220000 definitions=main-1806200044 Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org 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(0x10030)" >> uprobe_events bash: echo: write error: Invalid argument # dmesg trace_kprobe: Reference counter offset mismatch. One exception to this is 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 entry. Signed-off-by: Ravi Bangoria --- kernel/trace/trace_uprobe.c | 36 ++++++++++++++++++++++++++++++++++-- 1 file changed, 34 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index bf2be09..7dd86f3 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -324,6 +324,34 @@ 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. Only one exception to this is when we are + * replacing old trace_uprobe with new one(same group/event). + */ +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); + if (!new->ref_ctr_offset) + return old; + + list_for_each_entry(tmp, &uprobe_list, list) { + if (new_inode == d_real_inode(tmp->path.dentry) && + new->offset == tmp->offset && + new->ref_ctr_offset != tmp->ref_ctr_offset && + tmp != old) { + 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) { @@ -333,8 +361,12 @@ 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); -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html