From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org F35B3601A8 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932622AbeFFIeZ (ORCPT + 25 others); Wed, 6 Jun 2018 04:34:25 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:34628 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932397AbeFFIeV (ORCPT ); Wed, 6 Jun 2018 04:34:21 -0400 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 5/7] Uprobes/sdt: Prevent multiple reference counter for same uprobe Date: Wed, 6 Jun 2018 14:03:42 +0530 X-Mailer: git-send-email 2.14.4 In-Reply-To: <20180606083344.31320-1-ravi.bangoria@linux.ibm.com> References: <20180606083344.31320-1-ravi.bangoria@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18060608-0012-0000-0000-0000027BA8CB X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18060608-0013-0000-0000-000020ACB1F9 Message-Id: <20180606083344.31320-6-ravi.bangoria@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-06-06_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-1806060098 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Even if we don't allow to create same uprobe with different reference counter offset via trace_uprobe, user can still create such uprobes by creating one uprobe using trace_uprobe and other by directly calling uprobe_register() from kernel module. Prevent such scenarios. Note that, we are restricting user to not use both ways (trace_uprobe and kernel module) simultaneously. Ex, User can not trace single uprobe (with reference counter) simultaneously with Systemtap and perf at the same time. Signed-off-by: Ravi Bangoria --- kernel/events/uprobes.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 279c8fc..5e07f99 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -526,6 +526,12 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset, cur_uprobe = insert_uprobe(uprobe); /* a uprobe exists for this inode:offset combination */ if (cur_uprobe) { + if (cur_uprobe->ref_ctr_offset != uprobe->ref_ctr_offset) { + pr_warn("Err: Reference counter mismatch.\n"); + put_uprobe(cur_uprobe); + kfree(uprobe); + return ERR_PTR(-EINVAL); + } kfree(uprobe); uprobe = cur_uprobe; } @@ -1184,6 +1190,9 @@ static int __uprobe_register(struct inode *inode, loff_t offset, uprobe = alloc_uprobe(inode, offset, ref_ctr_offset); if (!uprobe) return -ENOMEM; + if (IS_ERR(uprobe)) + return PTR_ERR(uprobe); + /* * We can race with uprobe_unregister()->delete_uprobe(). * Check uprobe_is_active() and retry if it is false. -- 1.8.3.1