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 3D506A00BE; Tue, 10 May 2022 11:14:25 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id C4513406B4; Tue, 10 May 2022 11:14:24 +0200 (CEST) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by mails.dpdk.org (Postfix) with ESMTP id BACE44069D for ; Tue, 10 May 2022 11:14:23 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1652174063; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qVx21HW7zShPjGKIAXzBydFWSKbxG7fMmo1c01ahZAQ=; b=N/L4MNyAglpEcgDDu73d065KpM5+S9mzVkjdgcjepwhrty/S7Zs5R5dkdwSTTRGGsUch49 1tKo34Ombr4GanhKwM5bStWzJ1HH0f/AvG4YPta/sz1nOQvEYV314eCNwAq5VSeivTPTfi Kw6E9LrkLTg1kv2HKqZ59aNTH24woh8= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-140-4ZkV01RxMsSSM1SWWBYh2Q-1; Tue, 10 May 2022 05:14:20 -0400 X-MC-Unique: 4ZkV01RxMsSSM1SWWBYh2Q-1 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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id 98BEB85A5BE; Tue, 10 May 2022 09:14:19 +0000 (UTC) Received: from [10.39.208.28] (unknown [10.39.208.28]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E8AD4111D78E; Tue, 10 May 2022 09:14:02 +0000 (UTC) Message-ID: Date: Tue, 10 May 2022 11:14:01 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.1.0 Subject: Re: [PATCH] vhost: add runtime locking check in unsafe APIs To: "Hu, Jiayu" , "dev@dpdk.org" , "Xia, Chenbo" , "Ding, Xuan" , "Jiang, Cheng1" , "Pai G, Sunil" , "david.marchand@redhat.com" References: <20220510082528.1229104-1-maxime.coquelin@redhat.com> <0003ad4c95bc4057938a9979efce4889@intel.com> From: Maxime Coquelin In-Reply-To: <0003ad4c95bc4057938a9979efce4889@intel.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=maxime.coquelin@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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 Hi Jiayu, On 5/10/22 11:00, Hu, Jiayu wrote: > Hi Maxime, > > This is a good idea to add the lock check below. But I have two > questions: > First, rte_vhost_clear_queue_thread_unsafe() is thread unsafe. > Why doesn't add the check for it? Yes, I missed it. Thanks for spotting that! > Second, dev->notify_ops->destroy_device() is called without taking > the lock. If vhost applications try to clear inflight packets or even > unregister asynchronous data-path in this callback, rather than in > dev->notify_ops->vring_state_changed(), asynchronous APIs below > will return -1. How to handle this situation? You should call the proper safe/unsafe API depending on the context. The idea of this patch was to catch corner cases like this one, so good it helped to identify this issue. Thanks, Maxime > Thanks, > Jiayu > >> -----Original Message----- >> From: Maxime Coquelin >> Sent: Tuesday, May 10, 2022 4:25 PM >> To: dev@dpdk.org; Xia, Chenbo ; Ding, Xuan >> ; Hu, Jiayu ; Jiang, Cheng1 >> ; Pai G, Sunil ; >> david.marchand@redhat.com >> Cc: Maxime Coquelin >> Subject: [PATCH] vhost: add runtime locking check in unsafe APIs >> >> This patch adds runtime checks in unsafe Vhost async APIs, to ensure the >> access lock is taken. >> >> The detection won't work every time, as another thread could take the lock, >> but it would help to detect misuse of these unsafe API. >> >> Signed-off-by: Maxime Coquelin >> --- >> lib/vhost/vhost.c | 18 ++++++++++++++++++ >> 1 file changed, 18 insertions(+) >> >> diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c index >> df0bb9d043..39cbeb415c 100644 >> --- a/lib/vhost/vhost.c >> +++ b/lib/vhost/vhost.c >> @@ -1732,6 +1732,12 @@ >> rte_vhost_async_channel_register_thread_unsafe(int vid, uint16_t queue_id) >> if (unlikely(vq == NULL || !dev->async_copy)) >> return -1; >> >> + if (unlikely(!rte_spinlock_is_locked(&vq->access_lock))) { >> + VHOST_LOG_CONFIG(ERR, "(%s) %s() called without access >> lock taken.\n", >> + dev->ifname, __func__); >> + return -1; >> + } >> + >> return async_channel_register(vid, queue_id); } >> >> @@ -1796,6 +1802,12 @@ >> rte_vhost_async_channel_unregister_thread_unsafe(int vid, uint16_t >> queue_id) >> if (vq == NULL) >> return -1; >> >> + if (unlikely(!rte_spinlock_is_locked(&vq->access_lock))) { >> + VHOST_LOG_CONFIG(ERR, "(%s) %s() called without access >> lock taken.\n", >> + dev->ifname, __func__); >> + return -1; >> + } >> + >> if (!vq->async) >> return 0; >> >> @@ -1925,6 +1937,12 @@ rte_vhost_async_get_inflight_thread_unsafe(int >> vid, uint16_t queue_id) >> if (vq == NULL) >> return ret; >> >> + if (unlikely(!rte_spinlock_is_locked(&vq->access_lock))) { >> + VHOST_LOG_CONFIG(ERR, "(%s) %s() called without access >> lock taken.\n", >> + dev->ifname, __func__); >> + return -1; >> + } >> + >> if (!vq->async) >> return ret; >> >> -- >> 2.35.1 >