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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 DB989C3279B for ; Fri, 6 Jul 2018 18:59:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F731208DF for ; Fri, 6 Jul 2018 18:59:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8F731208DF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.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 S934617AbeGFS7B (ORCPT ); Fri, 6 Jul 2018 14:59:01 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:52462 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S934201AbeGFS67 (ORCPT ); Fri, 6 Jul 2018 14:58:59 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7256C34687; Fri, 6 Jul 2018 18:58:59 +0000 (UTC) Received: from [10.10.121.173] (ovpn-121-173.rdu2.redhat.com [10.10.121.173]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3D286111DCF2; Fri, 6 Jul 2018 18:58:58 +0000 (UTC) Subject: Re: [PATCH v3 3/3] uio: fix crash after the device is unregistered To: xiubli@redhat.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org References: <1530845836-49101-1-git-send-email-xiubli@redhat.com> <1530845836-49101-4-git-send-email-xiubli@redhat.com> Cc: hamish.martin@alliedtelesis.co.nz, jannh@google.com, pkalever@redhat.com, pkarampu@redhat.com, atumball@redhat.com, sabose@redhat.com From: Mike Christie Message-ID: <5B3FBBF1.9080902@redhat.com> Date: Fri, 6 Jul 2018 13:58:57 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <1530845836-49101-4-git-send-email-xiubli@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Fri, 06 Jul 2018 18:58:59 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Fri, 06 Jul 2018 18:58:59 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'mchristi@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/05/2018 09:57 PM, xiubli@redhat.com wrote: > void uio_event_notify(struct uio_info *info) > { > - struct uio_device *idev = info->uio_dev; > + struct uio_device *idev; > + > + if (!info) > + return; > + > + idev = info->uio_dev; > For this one too, I am not sure if it is needed. uio_interrupt -> uio_event_notify. See other mail. driver XYZ -> uio_event_notify. I think drivers need to handle this and set some bits and/or perform some cleanup to make sure they are not calling uio_event_notify after it has called uio_unregister_device. The problem with the above test is if they do not they could have called uio_unregister_device right after the info test so you could still hit the problem.