From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rich Lane Subject: Re: [PATCH v2 1/1] vhost: fix leak of fds and mmaps Date: Tue, 19 Jan 2016 10:13:23 -0800 Message-ID: References: <1452032049-94324-1-git-send-email-rlane@bigswitch.com> <1453060638-58510-1-git-send-email-rlane@bigswitch.com> <20160118075808.GZ19531@yliu-dev.sh.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: dev@dpdk.org To: Yuanhan Liu Return-path: Received: from mail-vk0-f41.google.com (mail-vk0-f41.google.com [209.85.213.41]) by dpdk.org (Postfix) with ESMTP id 2F9875A32 for ; Tue, 19 Jan 2016 19:13:24 +0100 (CET) Received: by mail-vk0-f41.google.com with SMTP id k1so353008838vkb.2 for ; Tue, 19 Jan 2016 10:13:24 -0800 (PST) In-Reply-To: <20160118075808.GZ19531@yliu-dev.sh.intel.com> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Sun, Jan 17, 2016 at 11:58 PM, Yuanhan Liu wrote: > On Sun, Jan 17, 2016 at 11:57:18AM -0800, Rich Lane wrote: > > The common vhost code only supported a single mmap per device. vhost-user > > worked around this by saving the address/length/fd of each mmap after > the end > > of the rte_virtio_memory struct. This only works if the vhost-user code > frees > > dev->mem, since the common code is unaware of the extra info. The > > VHOST_USER_RESET_OWNER message is one situation where the common code > frees > > dev->mem and leaks the fds and mappings. This happens every time I shut > down a > > VM. > > > > The new code calls back into the implementation (vhost-user or > vhost-cuse) to > > clean up these resources. > > > > The vhost-cuse changes are only compile tested. > > > > Signed-off-by: Rich Lane > > --- > > v1->v2: > > - Call into vhost-user/vhost-cuse to free mmaps. > > > > lib/librte_vhost/vhost-net.h | 6 ++++++ > > lib/librte_vhost/vhost_cuse/virtio-net-cdev.c | 12 ++++++++++++ > > lib/librte_vhost/vhost_user/vhost-net-user.c | 1 - > > lib/librte_vhost/vhost_user/virtio-net-user.c | 25 > ++++++++++--------------- > > lib/librte_vhost/vhost_user/virtio-net-user.h | 1 - > > lib/librte_vhost/virtio-net.c | 8 +------- > > 6 files changed, 29 insertions(+), 24 deletions(-) > > > > diff --git a/lib/librte_vhost/vhost-net.h b/lib/librte_vhost/vhost-net.h > > index c69b60b..e8d7477 100644 > > --- a/lib/librte_vhost/vhost-net.h > > +++ b/lib/librte_vhost/vhost-net.h > > @@ -115,4 +115,10 @@ struct vhost_net_device_ops { > > > > > > struct vhost_net_device_ops const *get_virtio_net_callbacks(void); > > + > > +/* > > + * Implementation-specific cleanup. Defined by vhost-cuse and > vhost-user. > > + */ > > +void vhost_impl_cleanup(struct virtio_net *dev); > > TBH, I am not quite like "_impl_"; maybe "_backend_" is better? > If you have a strong preference I will change it. Let me know. > OTOH, what I thought of has slight difference than yours: not > necessary to export a function, but instead, call the vhost > backend specific unmap function inside the backend itself. Say, > call vhost_user_unmap() on RESET_OWNER and connection close. > What do you think of that? The munmap must be done after the notify_ops->destroy_device callback. That means the backend can't call it before reset_owner() or destroy_device(). The munmap could be done afterwards, but that requires saving dev->mem in the caller in the case of destroy_device. The cleanest solution is for the vhost common code to ask the backend to clean up at the correct time.