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=-7.6 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 3E2DBC4708A for ; Thu, 27 May 2021 05:00:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 224DF6128D for ; Thu, 27 May 2021 05:00:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234928AbhE0FCA (ORCPT ); Thu, 27 May 2021 01:02:00 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:57617 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233565AbhE0FB5 (ORCPT ); Thu, 27 May 2021 01:01:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1622091625; 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=WvNDULJK9zHRMwqe44K4RR3WKdtWUGMATeJjP7wtcZY=; b=Fhldo+YVuaqR8B6kgE4vBkuNUbrVQcmUO5Vu4nCykBoNFl2MwcqwH0O/ZNRC2sQjfvmFz5 fVSE3PxIt0ykDX8QIvr2D2mm3K8Xyjv1wmfAUTvqf62Nz+RXryf5YYmQBxv39XxjgVc8h+ l4IkG9WrGgmEyE0BjVA1ArgMW+YidEk= Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-478-T92fe91yNzabtcDn1OaVVA-1; Thu, 27 May 2021 01:00:23 -0400 X-MC-Unique: T92fe91yNzabtcDn1OaVVA-1 Received: by mail-pf1-f200.google.com with SMTP id o11-20020a62f90b0000b02902db3045f898so2097280pfh.23 for ; Wed, 26 May 2021 22:00:23 -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=WvNDULJK9zHRMwqe44K4RR3WKdtWUGMATeJjP7wtcZY=; b=TBTW6785chIB2kCpBQyZzO01rD0Ai+gZ5OlJcf1tQH7NbjGUrOnorvqx+2qUJY2RDN p1dR4ffK/tPMfHb2FQ2frNZWBneIimRRs4OEVMxNAbrONMxzBPgAjWbZCjRXAVfVUx/A CHbBoT6Rh794CXSFER2wmRty6GzkpCR5j83STGaldYocItA2+okeaUvOmdXCyQxC9jhU 4/TVvw4zHEFkaQfrFUyBFCduhvOWivVeV36aJJpbNF7NjggnSIXbQYh3fsfx/BpSavEw ZsPt4ZuAhUbZVwTWxDqtiG7nGIMySkm5Omk609E1oOpwJCnCa9GMHQUeIRpvRfli3aOV 16rQ== X-Gm-Message-State: AOAM531LWqWnbETjWeJbx7fDcFsVxxb7jJxREbBL+VlU8jbDnDF8snKu GA8Zv4bRv3RHPSFRLW5aa0rmRe6STnKF+I9INGSLcVJa5R2SPnWWf3neR7fG53cQc1k6ndGgVyC /z0QWRB8AMel5/oOoWO4zT2domPrjuL3sXmuaqLb3rDHy55hq5atz6YlgWhHb+/+D2Wyo5i8owJ bv X-Received: by 2002:a17:90b:1d8f:: with SMTP id pf15mr1854547pjb.36.1622091617059; Wed, 26 May 2021 22:00:17 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxbQssOI3XI76V4pKYYsFesmyrvxjTc0EKTWn6Zl6xKwlpjIji0dLlRJIWAqJ1uNqyHlcKbWw== X-Received: by 2002:a17:90b:1d8f:: with SMTP id pf15mr1854461pjb.36.1622091616242; Wed, 26 May 2021 22:00:16 -0700 (PDT) Received: from wangxiaodeMacBook-Air.local ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id u5sm715334pfi.179.2021.05.26.22.00.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 26 May 2021 22:00:15 -0700 (PDT) Subject: Re: [PATCH v7 11/12] vduse: Introduce VDUSE - vDPA Device in Userspace To: Yongji Xie Cc: "Michael S. Tsirkin" , Stefan Hajnoczi , Stefano Garzarella , Parav Pandit , Christoph Hellwig , Christian Brauner , Randy Dunlap , Matthew Wilcox , Al Viro , Jens Axboe , bcrl@kvack.org, Jonathan Corbet , =?UTF-8?Q?Mika_Penttil=c3=a4?= , Dan Carpenter , joro@8bytes.org, virtualization , netdev@vger.kernel.org, kvm , linux-fsdevel@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel References: <20210517095513.850-1-xieyongji@bytedance.com> <20210517095513.850-12-xieyongji@bytedance.com> <3740c7eb-e457-07f3-5048-917c8606275d@redhat.com> From: Jason Wang Message-ID: <5a68bb7c-fd05-ce02-cd61-8a601055c604@redhat.com> Date: Thu, 27 May 2021 13:00:07 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2021/5/27 下午12:57, Yongji Xie 写道: > On Thu, May 27, 2021 at 12:13 PM Jason Wang wrote: >> >> 在 2021/5/17 下午5:55, Xie Yongji 写道: >>> + >>> +static int vduse_dev_msg_sync(struct vduse_dev *dev, >>> + struct vduse_dev_msg *msg) >>> +{ >>> + init_waitqueue_head(&msg->waitq); >>> + spin_lock(&dev->msg_lock); >>> + vduse_enqueue_msg(&dev->send_list, msg); >>> + wake_up(&dev->waitq); >>> + spin_unlock(&dev->msg_lock); >>> + wait_event_killable(msg->waitq, msg->completed); >> >> What happens if the userspace(malicous) doesn't give a response forever? >> >> It looks like a DOS. If yes, we need to consider a way to fix that. >> > How about using wait_event_killable_timeout() instead? Probably, and then we need choose a suitable timeout and more important, need to report the failure to virtio. Thanks > > Thanks, > Yongji >