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=ham 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 309FB7D071 for ; Mon, 16 Jul 2018 08:20:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729859AbeGPIqh (ORCPT ); Mon, 16 Jul 2018 04:46:37 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:43826 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729615AbeGPIqh (ORCPT ); Mon, 16 Jul 2018 04:46:37 -0400 Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w6G8JfZv095858 for ; Mon, 16 Jul 2018 04:20:24 -0400 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2k8jaak2qa-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 16 Jul 2018 04:20:23 -0400 Received: from localhost by e06smtp03.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) Mon, 16 Jul 2018 09:20:15 +0100 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w6G8KEhn21364892 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 16 Jul 2018 08:20:14 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id ECA56A4040; Mon, 16 Jul 2018 11:20:32 +0100 (BST) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 76A61A404D; Mon, 16 Jul 2018 11:20:29 +0100 (BST) Received: from [9.124.31.217] (unknown [9.124.31.217]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 16 Jul 2018 11:20:29 +0100 (BST) Subject: Re: [PATCH v5 06/10] Uprobes: Support SDT markers having reference count (semaphore) To: Song Liu Cc: Oleg Nesterov , srikar@linux.vnet.ibm.com, rostedt@goodmis.org, mhiramat@kernel.org, Peter Zijlstra , mingo@redhat.com, acme@kernel.org, alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org, open list , corbet@lwn.net, linux-doc@vger.kernel.org, ananth@linux.vnet.ibm.com, alexis.berlemont@gmail.com, naveen.n.rao@linux.vnet.ibm.com, linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org, linux@armlinux.org.uk, ralf@linux-mips.org, paul.burton@mips.com, Ravi Bangoria References: <20180628052209.13056-7-ravi.bangoria@linux.ibm.com> <20180701210935.GA14404@redhat.com> <0c543791-f3b7-5a4b-f002-e1c76bb430c0@linux.ibm.com> <20180702180156.GA31400@redhat.com> <20180703163645.GA23144@redhat.com> <20180703172543.GC23144@redhat.com> <20180710152527.GA3616@redhat.com> <6e3ff60b-267a-d49d-4ebb-c4264f9c034b@linux.ibm.com> <20180712145849.GB15265@redhat.com> <9b062a19-d9a7-b360-26b1-d28b8dfc35a3@linux.ibm.com> From: Ravi Bangoria Date: Mon, 16 Jul 2018 13:50:10 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 18071608-0012-0000-0000-0000028A991D X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18071608-0013-0000-0000-000020BC503B Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-07-16_02:,, 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=898 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1806210000 definitions=main-1807160100 Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Hi Song, On 07/14/2018 05:20 AM, Song Liu wrote: > > Hmm... what happens when we have multiple uprobes sharing the same > reference counter? It feels equally complicate to me. Or did I miss any > cases here? As far as I can think of, it should be handled by default. No special treatment needed for this. ... > > This patch tries to resolve this imbalance by passing extra flag > "restore_insn" to probe_event_disable(). > > Signed-off-by: Song Liu Ah cool. Seems this will make them balanced. But is it fine to change uprobe_unregister()? It's already an ABI. No other way around? Also, one more source of imbalance is this condition: if (is_register) flags |= VM_WRITE; in valid_vma(). You need to take care of that as well. Thanks, Ravi -- 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