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=-7.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 61239C433DB for ; Tue, 12 Jan 2021 18:39:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0D0FB2311F for ; Tue, 12 Jan 2021 18:39:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406001AbhALSjJ (ORCPT ); Tue, 12 Jan 2021 13:39:09 -0500 Received: from aserp2130.oracle.com ([141.146.126.79]:59260 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728112AbhALSjI (ORCPT ); Tue, 12 Jan 2021 13:39:08 -0500 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 10CIDWKk139880; Tue, 12 Jan 2021 18:38:26 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2020-01-29; bh=8KxyImXKDVv3i4kRA62ts8srdgqwl4yl8Hqk9cIzWw0=; b=V3DpagR4gri/p+U59UIkZUgcRBbCkx2Qgu0Fb+WpXHWV1V23Spy44fkismyWs5+9xG+z xSI1g/irj96UYi0U/0tnalGYxci8thh3KVDoD6PyuAL+dkqNuJjQ4XX9Bn7gzEqHg/TZ FxwfYiCt2TpKjerQLiAFr+zfCyGKgd1VhiSoJfc/p9mfcbIVC0ZSk+FZKUXgrdtm9S9P PqshMtRkxaCsPB+opMf2ciWrEBWBY0V/r4xlex1ls5/U+QEUfjXmkdBNh4g5DIkVJIa4 XyqeC84ZG7qAl2SKL3fT7dKJh6zbugnecMXlS25UoCuANYGg16Ey6E4TQM+6e0Fm7UPa 9A== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by aserp2130.oracle.com with ESMTP id 360kg1quqn-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 12 Jan 2021 18:38:26 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 10CIG28w140849; Tue, 12 Jan 2021 18:36:25 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3030.oracle.com with ESMTP id 360key7acq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 12 Jan 2021 18:36:25 +0000 Received: from abhmp0016.oracle.com (abhmp0016.oracle.com [141.146.116.22]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 10CIaPAs032717; Tue, 12 Jan 2021 18:36:25 GMT Received: from [20.15.0.204] (/73.88.28.6) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 12 Jan 2021 10:36:25 -0800 Subject: Re: [PATCH] scsi: target: tcmu: Fix wrong uio handling causing big memory leak To: Bodo Stroesser , linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-kernel@vger.kernel.org, "Martin K. Petersen" Cc: Greg Kroah-Hartman References: <20201218141534.9918-1-bostroesser@gmail.com> From: Mike Christie Message-ID: <73dc2d01-6398-c1d1-df47-66034d184eec@oracle.com> Date: Tue, 12 Jan 2021 12:36:24 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201218141534.9918-1-bostroesser@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9862 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 bulkscore=0 malwarescore=0 suspectscore=0 adultscore=0 spamscore=0 mlxlogscore=999 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101120108 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9862 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 suspectscore=0 clxscore=1011 impostorscore=0 spamscore=0 priorityscore=1501 mlxscore=0 phishscore=0 mlxlogscore=999 bulkscore=0 adultscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101120108 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/18/20 8:15 AM, Bodo Stroesser wrote: > tcmu calls uio_unregister_device from tcmu_destroy_device. > After that uio will never call tcmu_release for this device. > If userspace still had the uio device open and / or mmap'ed > during uio_unregister_device, tcmu_release will not be called and > udev->kref will never go down to 0. > I didn't get why the release function is not called if you call uio_unregister_device while a device is open. Does the device_destroy call in uio_unregister_device completely free the device or does it set some bits so uio_release is not called later? Do other drivers hit this? Should uio have refcounting so uio_release is called when the last ref (from userspace open/close/mmap calls and from the kernel by drivers like target_core_user) is done?