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=-13.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 E4A65C07E9A for ; Mon, 5 Jul 2021 03:48:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE2866135E for ; Mon, 5 Jul 2021 03:48:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229807AbhGEDv0 (ORCPT ); Sun, 4 Jul 2021 23:51:26 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:28798 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229722AbhGEDvZ (ORCPT ); Sun, 4 Jul 2021 23:51:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625456928; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=25P6+qOObwDiaurdWnfUZ/5fIR3I7PXs4U3cGO2pDNQ=; b=ZxfKnzuUsmBJ24UVTsrzkAeYBQNnDiNzUV/bqxYppgDq1SU3RyEdzt0Se4hoHuUpnk4G1x Gltq3yKVXEelmzk5iBAO35A5/LKb2D4RbY1O6zdlmoHUos8D9oOYnEXkUw36XZInZOIaid +p05T5anyVxz+wzT9RmF1sq4ZNfyDLQ= Received: from mail-pg1-f199.google.com (mail-pg1-f199.google.com [209.85.215.199]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-519-_HevpuGROUCrMfsWHfcTwg-1; Sun, 04 Jul 2021 23:48:47 -0400 X-MC-Unique: _HevpuGROUCrMfsWHfcTwg-1 Received: by mail-pg1-f199.google.com with SMTP id d28-20020a634f1c0000b02902238495b6a7so12713370pgb.16 for ; Sun, 04 Jul 2021 20:48:47 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=25P6+qOObwDiaurdWnfUZ/5fIR3I7PXs4U3cGO2pDNQ=; b=XDV0t7LLSEVWpxlqpdGd8AQBktLjxYj3FADhqIc9ZB74hJaMA7Bk477mHx3OZ2BNcq bzgWVDcswJk+yS4eaZbpTcW11zAZVeOBVK/wfOUeBs/gbzSlgNl7DdjXdpr/1CNG9d1N dcXHbwW5t1rfmp9ghULNz9/CmquAVJWDATJFdIOxdi2/P6WH2dm6ySpNpOI1K+9ENsfQ WENJqL3mS9dMWHcUekbbSM0gOF3OMmtOK5m6KIuKU1D6ZplMPJjKtVuSQwj5E5ZmITPB MxHhIquC/2+tAhNVQjtbEFhll/cD8pviXyx7YDkKDWkXlJvlw01P12KQNuL4h7ySy00i 7U1w== X-Gm-Message-State: AOAM531OCuY+Wo8a1yxQ5qU5Stcss/ukxsl+Mlo7AuTEn4XAvIf6nIl4 v1yMHVziAaMUSkaQbo/T3rAkmJ4FYmhqwitoiec7kUjJHhS2YYOYVpqZaYsJAQt79Iygdo68TIr 9F7TCV2OLsTEHG0YZcQTBaOyNFVGObqORaTxwGJG0TIFPs9WLSt7uGD5KOEQIkEZCtiIjBGAWlt 4u X-Received: by 2002:a63:f955:: with SMTP id q21mr13651952pgk.448.1625456926315; Sun, 04 Jul 2021 20:48:46 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxh+8a0lcafys7ntL0qYOJsYQ0uxw1HqHLN2/UyNlqrNDJW0H4QdQRaegwbRorAJ1FTbNPV1A== X-Received: by 2002:a63:f955:: with SMTP id q21mr13651917pgk.448.1625456925713; Sun, 04 Jul 2021 20:48:45 -0700 (PDT) Received: from wangxiaodeMacBook-Air.local ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id f193sm2380694pfa.185.2021.07.04.20.48.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 04 Jul 2021 20:48:45 -0700 (PDT) Subject: Re: [RFC PATCH] vhost-vdpa: mark vhost device invalid to reflect vdpa device unregistration To: gautam.dawar@xilinx.com Cc: martinh@xilinx.com, hanand@xilinx.com, gdawar@xilinx.com, "Michael S. Tsirkin" , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20210704205205.6132-1-gdawar@xilinx.com> From: Jason Wang Message-ID: <3d02b8f5-0a6b-e8d1-533d-8503da3fcc4e@redhat.com> Date: Mon, 5 Jul 2021 11:48:36 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210704205205.6132-1-gdawar@xilinx.com> Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ÔÚ 2021/7/5 ÉÏÎç4:52, gautam.dawar@xilinx.com дµÀ: > vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); > @@ -1091,11 +1122,13 @@ static void vhost_vdpa_remove(struct vdpa_device *vdpa) > opened = atomic_cmpxchg(&v->opened, 0, 1); > if (!opened) > break; > - wait_for_completion_timeout(&v->completion, > - msecs_to_jiffies(1000)); > - dev_warn_once(&v->dev, > - "%s waiting for/dev/%s to be closed\n", > - __func__, dev_name(&v->dev)); > + if (!wait_for_completion_timeout(&v->completion, > + msecs_to_jiffies(1000))) { > + dev_warn(&v->dev, > + "%s/dev/%s in use, continue..\n", > + __func__, dev_name(&v->dev)); > + break; > + } > } while (1); > > put_device(&v->dev); > + v->dev_invalid = true; Besides the mapping handling mentioned by Michael. I think this can lead use-after-free. put_device may release the memory. Another fundamental issue, vDPA is the parent of vhost-vDPA device. I'm not sure the device core can allow the parent to go away first. Thanks