From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 762B4A00C4; Thu, 5 May 2022 09:22:16 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 5B08640C35; Thu, 5 May 2022 09:22:16 +0200 (CEST) Received: from us-smtp-delivery-74.mimecast.com (us-smtp-delivery-74.mimecast.com [170.10.133.74]) by mails.dpdk.org (Postfix) with ESMTP id 7D8FE40042 for ; Thu, 5 May 2022 09:22:14 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1651735333; 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: in-reply-to:in-reply-to:references:references; bh=lffcWg1CvRUGco497jgMGTUbgJFCd9vSS22Lm3WjPWY=; b=Cl6RBESr6i7XvUxUx8Vb8rzTnqGeVeCWNIelPHqXPsefjOiaX2qJOhkiYaCsI2gekBxnRu KMceB8/SQucl4t0rqFC7bJL/GZom9fvQVlvPP5AzwR6Oo+qr/OTKoY+99wX1tjKfH7LwO+ usADaxTFn0/4uoWJdXeyJqfHbe3cLNQ= Received: from mail-lj1-f200.google.com (mail-lj1-f200.google.com [209.85.208.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-78-vZGqGUqSOpWfhkdwUjSrqQ-1; Thu, 05 May 2022 03:22:12 -0400 X-MC-Unique: vZGqGUqSOpWfhkdwUjSrqQ-1 Received: by mail-lj1-f200.google.com with SMTP id l13-20020a2e868d000000b0024f078d7ea0so1106845lji.4 for ; Thu, 05 May 2022 00:22:11 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=lffcWg1CvRUGco497jgMGTUbgJFCd9vSS22Lm3WjPWY=; b=uqvZK6kOt+/8zjKPJ1qjAwQYbB6rKYXGrJf18ttUh+jkwHV5LHRGobLwzlvp0MGi/H esuzB0laCn/iGNEVOpGqogyA0dBXgDIgIrCktujGvIIAmcEzDRyjrvnAGM9IpT8WadSt JQQzzAggMonP1uVqkP5djncTI0hCAzPTeifkDcDfQFYxLHnZOApWIa0yhhlnMIjFeKsS KwCquzApfHYDnvuiUsL2ZMsynkwwS2z0KKFVWU94k2fcEHqhDcASSjagaZxsT71M8kvu aStJaqTU1jG92R5hhR1maIzWWEbLJ04SV6UGypdZ/QN6v5t7BiNAV8oHVqFh1bEAAiiU HC6Q== X-Gm-Message-State: AOAM5313wmkC2jd0h5ifoOy8qEN0evkmGR+B3VlAl2SZdjcrjJh5OdBG NKXMn1OBSnwuwdaz9bTXmr2e8y+mXQ1mdI66Ruvn6WGrlFAKCy7/yv561aXqErpoUKzcGMEN0ED XOg4SFhTVLnjHY9nS4+0= X-Received: by 2002:a2e:9d90:0:b0:24f:224:8dfa with SMTP id c16-20020a2e9d90000000b0024f02248dfamr15098874ljj.46.1651735330527; Thu, 05 May 2022 00:22:10 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwRkrsE1wRdfES2gQXTwRbx77Kfr8dCHzH0zbbCsUK2gq8vuGcKcYhYs45xU5sURuwZq1170dYhSkrxysEuH68= X-Received: by 2002:a2e:9d90:0:b0:24f:224:8dfa with SMTP id c16-20020a2e9d90000000b0024f02248dfamr15098857ljj.46.1651735330305; Thu, 05 May 2022 00:22:10 -0700 (PDT) MIME-Version: 1.0 References: <20220505134008.2865-1-wenwux.ma@intel.com> In-Reply-To: <20220505134008.2865-1-wenwux.ma@intel.com> From: David Marchand Date: Thu, 5 May 2022 09:21:59 +0200 Message-ID: Subject: Re: [PATCH] vhost: fix deadlock when handling user messages To: Wenwu Ma Cc: Maxime Coquelin , "Xia, Chenbo" , dev , Jiayu Hu , "Wang, Yinan" , xingguang.he@intel.com Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dmarchan@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Hello, On Thu, May 5, 2022 at 7:42 AM Wenwu Ma wrote: > > In vhost_user_msg_handler(), if vhost message handling > failed, we should check whether the queue is locked and > release the lock before returning. Or, it will cause a > deadlock later. Fixes: 7f31d4ea05ca ("vhost: fix lock on device readiness notification") Cc: stable@dpdk.org > > Signed-off-by: Wenwu Ma > --- > lib/vhost/vhost_user.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c > index 1d390677fa..80a5df6e9d 100644 > --- a/lib/vhost/vhost_user.c > +++ b/lib/vhost/vhost_user.c > @@ -3113,6 +3113,8 @@ vhost_user_msg_handler(int vid, int fd) > send_vhost_reply(dev, fd, &ctx); > } else if (ret == RTE_VHOST_MSG_RESULT_ERR) { > VHOST_LOG_CONFIG(ERR, "(%s) vhost message handling failed.\n", dev->ifname); > + if (unlock_required) > + vhost_user_unlock_all_queue_pairs(dev); > return -1; > } > This fixes the issue, but my concern is that changes in the future might introduce a new return statement (forgetting to unlock). I suggest having a single return statement, like: diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c index 1d390677fa..4baf969ee0 100644 --- a/lib/vhost/vhost_user.c +++ b/lib/vhost/vhost_user.c @@ -2976,7 +2976,6 @@ vhost_user_msg_handler(int vid, int fd) return -1; } - ret = 0; request = ctx.msg.request.master; if (request > VHOST_USER_NONE && request < VHOST_USER_MAX && vhost_message_str[request]) { @@ -3113,9 +3112,11 @@ vhost_user_msg_handler(int vid, int fd) send_vhost_reply(dev, fd, &ctx); } else if (ret == RTE_VHOST_MSG_RESULT_ERR) { VHOST_LOG_CONFIG(ERR, "(%s) vhost message handling failed.\n", dev->ifname); - return -1; + ret = -1; + goto unlock; } + ret = 0; for (i = 0; i < dev->nr_vring; i++) { struct vhost_virtqueue *vq = dev->virtqueue[i]; bool cur_ready = vq_is_ready(dev, vq); @@ -3126,10 +3127,11 @@ vhost_user_msg_handler(int vid, int fd) } } +unlock: if (unlock_required) vhost_user_unlock_all_queue_pairs(dev); - if (!virtio_is_ready(dev)) + if (ret != 0 || !virtio_is_ready(dev)) goto out; /* @@ -3156,7 +3158,7 @@ vhost_user_msg_handler(int vid, int fd) } out: - return 0; + return ret; } static int process_slave_message_reply(struct virtio_net *dev, -- David Marchand