From patchwork Thu Jun 30 02:08:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 12900972 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 25FA2C43334 for ; Thu, 30 Jun 2022 02:08:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229623AbiF3CI1 (ORCPT ); Wed, 29 Jun 2022 22:08:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34342 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230467AbiF3CIV (ORCPT ); Wed, 29 Jun 2022 22:08:21 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id E147B11C15 for ; Wed, 29 Jun 2022 19:08:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1656554899; 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=rdzs+ejxlay4oS8U29luxVEbd5hmptD+SpCokSpGfUE=; b=X+qNkKvgJ9odIBw+ckuQzyqKKo5iMPM+wHqLQqPRNmn3qwNEL/ru+SMPn8tlsKbJR6+8Nb KXhzQsA3YF+udKUrecqVtbLfwvlVCQgN3kwlqoQ1acdABNM43UyMTBsdLWFnk1sJU81Ifo 9V6N95ACvUZOtBkyQ2uoDL/OaeAjJQ0= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-247-Tv97MKRaPRClFVcgWokWtw-1; Wed, 29 Jun 2022 22:08:15 -0400 X-MC-Unique: Tv97MKRaPRClFVcgWokWtw-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 7D6153C01DA3; Thu, 30 Jun 2022 02:08:14 +0000 (UTC) Received: from localhost.localdomain (ovpn-12-189.pek2.redhat.com [10.72.12.189]) by smtp.corp.redhat.com (Postfix) with ESMTP id 83BE3492CA3; Thu, 30 Jun 2022 02:08:11 +0000 (UTC) From: Jason Wang To: mst@redhat.com, jasowang@redhat.com, davem@davemloft.net, kuba@kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH V2] virtio-net: fix the race between refill work and close Date: Thu, 30 Jun 2022 10:08:05 +0800 Message-Id: <20220630020805.74658-2-jasowang@redhat.com> In-Reply-To: <20220630020805.74658-1-jasowang@redhat.com> References: <20220630020805.74658-1-jasowang@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 2.85 on 10.11.54.9 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 --- 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..21bf1e5c81ef 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(&vi->refill_lock); + vi->refill_work_enabled = true; + spin_unlock(&vi->refill_lock); +} + +static void disable_refill_work(struct virtnet_info *vi) +{ + spin_lock(&vi->refill_lock); + vi->refill_work_enabled = false; + spin_unlock(&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) ||