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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 A7CFEC46464 for ; Mon, 13 Aug 2018 10:03:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6252020BEC for ; Mon, 13 Aug 2018 10:03:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6252020BEC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.vnet.ibm.com 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 S1728995AbeHMMpN (ORCPT ); Mon, 13 Aug 2018 08:45:13 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:33488 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728660AbeHMMpM (ORCPT ); Mon, 13 Aug 2018 08:45:12 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w7D9whp6090180 for ; Mon, 13 Aug 2018 06:03:38 -0400 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ku5we52ck-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 13 Aug 2018 06:03:38 -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) Mon, 13 Aug 2018 11:03:32 +0100 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w7DA3Vf036503634 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 13 Aug 2018 10:03:31 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C06BE11C064; Mon, 13 Aug 2018 13:03:35 +0100 (BST) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EE89611C05B; Mon, 13 Aug 2018 13:03:32 +0100 (BST) Received: from linux.vnet.ibm.com (unknown [9.40.192.68]) by d06av25.portsmouth.uk.ibm.com (Postfix) with SMTP; Mon, 13 Aug 2018 13:03:32 +0100 (BST) Date: Mon, 13 Aug 2018 03:03:27 -0700 From: Srikar Dronamraju To: Ravi Bangoria Cc: oleg@redhat.com, rostedt@goodmis.org, mhiramat@kernel.org, liu.song.a23@gmail.com, 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, 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 Subject: Re: [PATCH v8 3/6] Uprobes: Support SDT markers having reference count (semaphore) Reply-To: Srikar Dronamraju References: <20180809041856.1547-1-ravi.bangoria@linux.ibm.com> <20180809041856.1547-4-ravi.bangoria@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20180809041856.1547-4-ravi.bangoria@linux.ibm.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-GCONF: 00 x-cbid: 18081310-4275-0000-0000-000002A90299 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18081310-4276-0000-0000-000037B21A10 Message-Id: <20180813100327.GF44470@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-08-13_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=965 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1808130110 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > + > +static int delayed_uprobe_add(struct uprobe *uprobe, struct mm_struct *mm) > +{ > + struct delayed_uprobe *du; > + > + if (delayed_uprobe_check(uprobe, mm)) > + return 0; > + > + du = kzalloc(sizeof(*du), GFP_KERNEL); > + if (!du) > + return -ENOMEM; > + > + du->uprobe = uprobe; > + du->mm = mm; > + list_add(&du->list, &delayed_uprobe_list); > + return 0; > +} > + Should we keep the delayed uprobe list per mm? That way we could avoid the global mutex lock. And the list to traverse would also be small. > > @@ -378,8 +557,15 @@ static struct uprobe *get_uprobe(struct uprobe *uprobe) > > static void put_uprobe(struct uprobe *uprobe) > { > - if (atomic_dec_and_test(&uprobe->ref)) > + if (atomic_dec_and_test(&uprobe->ref)) { > + /* > + * If application munmap(exec_vma) before uprobe_unregister() > + * gets called, we don't get a chance to remove uprobe from > + * delayed_uprobe_list in remove_breakpoint(). Do it here. > + */ > + delayed_uprobe_remove(uprobe, NULL); I am not getting this part. If unmap happens before unregister, why cant we use uprobe_munmap? what am I missing. > kfree(uprobe); > + } > } >