From patchwork Fri Jul 1 02:06:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 12902537 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56266C43334 for ; Fri, 1 Jul 2022 02:07:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232552AbiGACHJ (ORCPT ); Thu, 30 Jun 2022 22:07:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230008AbiGACHI (ORCPT ); Thu, 30 Jun 2022 22:07:08 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 74DD7443FB for ; Thu, 30 Jun 2022 19:07:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1656641226; 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; bh=Sdi8jNSnOdvWHR3wh2tv72zEmX4j3iNwttocgDASpHc=; b=i4zIE8d9P4/9iHJTU09HDshShdbEP+Okle+e3LB0Z/DPmGcn6F4uprg20f+qOq8fO41/rG 8mn+7Onf6ErkGzAyFwOPKjxpQFzWtdocgfdfDoZDnHu7pgg4RH8+OJdb7qkxZb7WDsQeZ8 QVny9ZKbPFvcxOjSjzCeP3rpBdDZav8= 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-104-l4E0IiP5PuKJpYdZoUpoqw-1; Thu, 30 Jun 2022 22:07:03 -0400 X-MC-Unique: l4E0IiP5PuKJpYdZoUpoqw-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D0B11101A588; Fri, 1 Jul 2022 02:07:02 +0000 (UTC) Received: from localhost.localdomain (ovpn-12-241.pek2.redhat.com [10.72.12.241]) by smtp.corp.redhat.com (Postfix) with ESMTP id CA6B041615A; Fri, 1 Jul 2022 02:06:58 +0000 (UTC) From: Jason Wang To: mst@redhat.com, jasowang@redhat.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: xuanzhuo@linux.alibaba.com Subject: [PATCH net V3] virtio-net: fix the race between refill work and close Date: Fri, 1 Jul 2022 10:06:55 +0800 Message-Id: <20220701020655.86532-1-jasowang@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 2.85 on 10.11.54.10 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org We try using cancel_delayed_work_sync() to prevent the work from enabling NAPI. This is insufficient since we don't disable the source of the refill work scheduling. This means an NAPI poll callback after cancel_delayed_work_sync() can schedule the refill work then can re-enable the NAPI that leads to use-after-free [1]. Since the work can enable NAPI, we can't simply disable NAPI before calling cancel_delayed_work_sync(). So fix this by introducing a dedicated boolean to control whether or not the work could be scheduled from NAPI. [1] ================================================================== BUG: KASAN: use-after-free in refill_work+0x43/0xd4 Read of size 2 at addr ffff88810562c92e by task kworker/2:1/42 CPU: 2 PID: 42 Comm: kworker/2:1 Not tainted 5.19.0-rc1+ #480 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Workqueue: events refill_work Call Trace: dump_stack_lvl+0x34/0x44 print_report.cold+0xbb/0x6ac ? _printk+0xad/0xde ? refill_work+0x43/0xd4 kasan_report+0xa8/0x130 ? refill_work+0x43/0xd4 refill_work+0x43/0xd4 process_one_work+0x43d/0x780 worker_thread+0x2a0/0x6f0 ? process_one_work+0x780/0x780 kthread+0x167/0x1a0 ? kthread_exit+0x50/0x50 ret_from_fork+0x22/0x30 ... Fixes: b2baed69e605c ("virtio_net: set/cancel work on ndo_open/ndo_stop") Signed-off-by: Jason Wang --- Changes since V2: - use spin_unlock()/lock_bh() in open/stop to synchronize with bh Changes since V1: - Tweak the changelog --- drivers/net/virtio_net.c | 38 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 36 insertions(+), 2 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index db05b5e930be..83ea57ad4eb5 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -251,6 +251,12 @@ struct virtnet_info { /* Does the affinity hint is set for virtqueues? */ bool affinity_hint_set; + /* Is refill work enabled? */ + bool refill_work_enabled; + + /* The lock to synchronize the access to refill_work_enabled */ + spinlock_t refill_lock; + /* CPU hotplug instances for online & dead */ struct hlist_node node; struct hlist_node node_dead; @@ -348,6 +354,20 @@ static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask) return p; } +static void enable_refill_work(struct virtnet_info *vi) +{ + spin_lock_bh(&vi->refill_lock); + vi->refill_work_enabled = true; + spin_unlock_bh(&vi->refill_lock); +} + +static void disable_refill_work(struct virtnet_info *vi) +{ + spin_lock_bh(&vi->refill_lock); + vi->refill_work_enabled = false; + spin_unlock_bh(&vi->refill_lock); +} + static void virtqueue_napi_schedule(struct napi_struct *napi, struct virtqueue *vq) { @@ -1527,8 +1547,12 @@ static int virtnet_receive(struct receive_queue *rq, int budget, } if (rq->vq->num_free > min((unsigned int)budget, virtqueue_get_vring_size(rq->vq)) / 2) { - if (!try_fill_recv(vi, rq, GFP_ATOMIC)) - schedule_delayed_work(&vi->refill, 0); + if (!try_fill_recv(vi, rq, GFP_ATOMIC)) { + spin_lock(&vi->refill_lock); + if (vi->refill_work_enabled) + schedule_delayed_work(&vi->refill, 0); + spin_unlock(&vi->refill_lock); + } } u64_stats_update_begin(&rq->stats.syncp); @@ -1651,6 +1675,8 @@ static int virtnet_open(struct net_device *dev) struct virtnet_info *vi = netdev_priv(dev); int i, err; + enable_refill_work(vi); + for (i = 0; i < vi->max_queue_pairs; i++) { if (i < vi->curr_queue_pairs) /* Make sure we have some buffers: if oom use wq. */ @@ -2033,6 +2059,8 @@ static int virtnet_close(struct net_device *dev) struct virtnet_info *vi = netdev_priv(dev); int i; + /* Make sure NAPI doesn't schedule refill work */ + disable_refill_work(vi); /* Make sure refill_work doesn't re-enable napi! */ cancel_delayed_work_sync(&vi->refill); @@ -2776,6 +2804,9 @@ static void virtnet_freeze_down(struct virtio_device *vdev) netif_tx_lock_bh(vi->dev); netif_device_detach(vi->dev); netif_tx_unlock_bh(vi->dev); + /* Make sure NAPI doesn't schedule refill work */ + disable_refill_work(vi); + /* Make sure refill_work doesn't re-enable napi! */ cancel_delayed_work_sync(&vi->refill); if (netif_running(vi->dev)) { @@ -2799,6 +2830,8 @@ static int virtnet_restore_up(struct virtio_device *vdev) virtio_device_ready(vdev); + enable_refill_work(vi); + if (netif_running(vi->dev)) { for (i = 0; i < vi->curr_queue_pairs; i++) if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL)) @@ -3548,6 +3581,7 @@ static int virtnet_probe(struct virtio_device *vdev) vdev->priv = vi; INIT_WORK(&vi->config_work, virtnet_config_changed_work); + spin_lock_init(&vi->refill_lock); /* If we can receive ANY GSO packets, we must allocate large ones. */ if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||