From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH net] virtio-net: fix page refcnt leaking when fail to allocate frag skb Date: Wed, 20 Nov 2013 11:00:41 +0800 Message-ID: <528C25D9.6030605@redhat.com> References: <1384848307-7217-1-git-send-email-jasowang@redhat.com> <1384869828.8604.97.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1384869828.8604.97.camel@edumazet-glaptop2.roam.corp.google.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Eric Dumazet Cc: Michael Dalton , mst@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Eric Dumazet List-Id: virtualization@lists.linuxfoundation.org On 11/19/2013 10:03 PM, Eric Dumazet wrote: > On Tue, 2013-11-19 at 16:05 +0800, Jason Wang wrote: >> > We need to drop the refcnt of page when we fail to allocate an skb for frag >> > list, otherwise it will be leaked. The bug was introduced by commit >> > 2613af0ed18a11d5c566a81f9a6510b73180660a ("virtio_net: migrate mergeable rx >> > buffers to page frag allocators"). >> > >> > Cc: Michael Dalton >> > Cc: Eric Dumazet >> > Cc: Rusty Russell >> > Cc: Michael S. Tsirkin >> > Signed-off-by: Jason Wang >> > --- >> > The patch was needed for 3.12 stable. > Good catch, but if we return from receive_mergeable() in the 'middle' > of the frags we would need for the current skb, who will > call the virtqueue_get_buf() to flush the remaining frags ? > > Don't we also need to call virtqueue_get_buf() like > > while (--num_buf) { > buf = virtqueue_get_buf(rq->vq, &len); > if (!buf) > break; > put_page(virt_to_head_page(buf)); > } > > ? Yes we need this, will send V2. Thanks From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753629Ab3KTDBH (ORCPT ); Tue, 19 Nov 2013 22:01:07 -0500 Received: from mx1.redhat.com ([209.132.183.28]:8757 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752234Ab3KTDBE (ORCPT ); Tue, 19 Nov 2013 22:01:04 -0500 Message-ID: <528C25D9.6030605@redhat.com> Date: Wed, 20 Nov 2013 11:00:41 +0800 From: Jason Wang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 MIME-Version: 1.0 To: Eric Dumazet CC: rusty@rustcorp.com.au, mst@redhat.com, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Michael Dalton , Eric Dumazet Subject: Re: [PATCH net] virtio-net: fix page refcnt leaking when fail to allocate frag skb References: <1384848307-7217-1-git-send-email-jasowang@redhat.com> <1384869828.8604.97.camel@edumazet-glaptop2.roam.corp.google.com> In-Reply-To: <1384869828.8604.97.camel@edumazet-glaptop2.roam.corp.google.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/19/2013 10:03 PM, Eric Dumazet wrote: > On Tue, 2013-11-19 at 16:05 +0800, Jason Wang wrote: >> > We need to drop the refcnt of page when we fail to allocate an skb for frag >> > list, otherwise it will be leaked. The bug was introduced by commit >> > 2613af0ed18a11d5c566a81f9a6510b73180660a ("virtio_net: migrate mergeable rx >> > buffers to page frag allocators"). >> > >> > Cc: Michael Dalton >> > Cc: Eric Dumazet >> > Cc: Rusty Russell >> > Cc: Michael S. Tsirkin >> > Signed-off-by: Jason Wang >> > --- >> > The patch was needed for 3.12 stable. > Good catch, but if we return from receive_mergeable() in the 'middle' > of the frags we would need for the current skb, who will > call the virtqueue_get_buf() to flush the remaining frags ? > > Don't we also need to call virtqueue_get_buf() like > > while (--num_buf) { > buf = virtqueue_get_buf(rq->vq, &len); > if (!buf) > break; > put_page(virt_to_head_page(buf)); > } > > ? Yes we need this, will send V2. Thanks