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Tsirkin" , linux-kernel@vger.kernel.org Cc: Tonghao Zhang , Willem de Bruijn , kernel test robot , "David S. Miller" , Jakub Kicinski , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, bpf@vger.kernel.org References: <20201018103122.454967-1-mst@redhat.com> From: Jason Wang Message-ID: Date: Tue, 20 Oct 2020 14:13:06 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201018103122.454967-1-mst@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 2020/10/20 上午1:32, Michael S. Tsirkin wrote: > This reverts commit 3618ad2a7c0e78e4258386394d5d5f92a3dbccf8. > > When the device does not have a control vq (e.g. when using a > version of QEMU based on upstream v0.10 or older, or when specifying > ctrl_vq=off,ctrl_rx=off,ctrl_vlan=off,ctrl_rx_extra=off,ctrl_mac_addr=off > for the device on the QEMU command line), that commit causes a crash: > > [ 72.229171] kernel BUG at drivers/net/virtio_net.c:1667! > [ 72.230266] invalid opcode: 0000 [#1] PREEMPT SMP > [ 72.231172] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.9.0-rc8-02934-g3618ad2a7c0e7 #1 > [ 72.231172] EIP: virtnet_send_command+0x120/0x140 > [ 72.231172] Code: 00 0f 94 c0 8b 7d f0 65 33 3d 14 00 00 00 75 1c 8d 65 f4 5b 5e 5f 5d c3 66 90 be 01 00 00 00 e9 6e ff ff ff 8d b6 00 > +00 00 00 <0f> 0b e8 d9 bb 82 00 eb 17 8d b4 26 00 00 00 00 8d b4 26 00 00 00 > [ 72.231172] EAX: 0000000d EBX: f72895c0 ECX: 00000017 EDX: 00000011 > [ 72.231172] ESI: f7197800 EDI: ed69bd00 EBP: ed69bcf4 ESP: ed69bc98 > [ 72.231172] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010246 > [ 72.231172] CR0: 80050033 CR2: 00000000 CR3: 02c84000 CR4: 000406f0 > [ 72.231172] Call Trace: > [ 72.231172] ? __virt_addr_valid+0x45/0x60 > [ 72.231172] ? ___cache_free+0x51f/0x760 > [ 72.231172] ? kobject_uevent_env+0xf4/0x560 > [ 72.231172] virtnet_set_guest_offloads+0x4d/0x80 > [ 72.231172] virtnet_set_features+0x85/0x120 > [ 72.231172] ? virtnet_set_guest_offloads+0x80/0x80 > [ 72.231172] __netdev_update_features+0x27a/0x8e0 > [ 72.231172] ? kobject_uevent+0xa/0x20 > [ 72.231172] ? netdev_register_kobject+0x12c/0x160 > [ 72.231172] register_netdevice+0x4fe/0x740 > [ 72.231172] register_netdev+0x1c/0x40 > [ 72.231172] virtnet_probe+0x728/0xb60 > [ 72.231172] ? _raw_spin_unlock+0x1d/0x40 > [ 72.231172] ? virtio_vdpa_get_status+0x1c/0x20 > [ 72.231172] virtio_dev_probe+0x1c6/0x271 > [ 72.231172] really_probe+0x195/0x2e0 > [ 72.231172] driver_probe_device+0x26/0x60 > [ 72.231172] device_driver_attach+0x49/0x60 > [ 72.231172] __driver_attach+0x46/0xc0 > [ 72.231172] ? device_driver_attach+0x60/0x60 > [ 72.231172] bus_add_driver+0x197/0x1c0 > [ 72.231172] driver_register+0x66/0xc0 > [ 72.231172] register_virtio_driver+0x1b/0x40 > [ 72.231172] virtio_net_driver_init+0x61/0x86 > [ 72.231172] ? veth_init+0x14/0x14 > [ 72.231172] do_one_initcall+0x76/0x2e4 > [ 72.231172] ? rdinit_setup+0x2a/0x2a > [ 72.231172] do_initcalls+0xb2/0xd5 > [ 72.231172] kernel_init_freeable+0x14f/0x179 > [ 72.231172] ? rest_init+0x100/0x100 > [ 72.231172] kernel_init+0xd/0xe0 > [ 72.231172] ret_from_fork+0x1c/0x30 > [ 72.231172] Modules linked in: > [ 72.269563] ---[ end trace a6ebc4afea0e6cb1 ]--- > > The reason is that virtnet_set_features now calls virtnet_set_guest_offloads > unconditionally, it used to only call it when there is something > to configure. > > If device does not have a control vq, everything breaks. > > Looking at this some more, I noticed that it's not really checking the > hardware too much. E.g. > > if ((dev->features ^ features) & NETIF_F_LRO) { > if (features & NETIF_F_LRO) > offloads |= GUEST_OFFLOAD_LRO_MASK & > vi->guest_offloads_capable; > else > offloads &= ~GUEST_OFFLOAD_LRO_MASK; > } > > and > > (1ULL << VIRTIO_NET_F_GUEST_TSO6) | \ > (1ULL << VIRTIO_NET_F_GUEST_ECN) | \ > (1ULL << VIRTIO_NET_F_GUEST_UFO)) > > But there's no guarantee that e.g. VIRTIO_NET_F_GUEST_TSO6 is set. > > If it isn't command should not send it. > > Further > > static int virtnet_set_features(struct net_device *dev, > netdev_features_t features) > { > struct virtnet_info *vi = netdev_priv(dev); > u64 offloads = vi->guest_offloads; > > seems wrong since guest_offloads is zero initialized, I'm not sure I get here. Did you mean vi->guest_offloads? We initialize it during probe     for (i = 0; i < ARRAY_SIZE(guest_offloads); i++)         if (virtio_has_feature(vi->vdev, guest_offloads[i]))             set_bit(guest_offloads[i], &vi->guest_offloads); > it does not reflect the state after reset which comes from > the features. > > Revert the original commit for now. > > Cc: Tonghao Zhang > Cc: Willem de Bruijn > Fixes: 3618ad2a7c0e7 ("virtio-net: ethtool configurable RXCSUM") > Reported-by: kernel test robot > Signed-off-by: Michael S. Tsirkin > --- > > changes from v1: > - clarify how to reproduce the bug in the log > > > drivers/net/virtio_net.c | 50 +++++++++++----------------------------- > 1 file changed, 13 insertions(+), 37 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index d2d2c4a53cf2..21b71148c532 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -68,8 +68,6 @@ static const unsigned long guest_offloads[] = { > (1ULL << VIRTIO_NET_F_GUEST_ECN) | \ > (1ULL << VIRTIO_NET_F_GUEST_UFO)) > > -#define GUEST_OFFLOAD_CSUM_MASK (1ULL << VIRTIO_NET_F_GUEST_CSUM) > - > struct virtnet_stat_desc { > char desc[ETH_GSTRING_LEN]; > size_t offset; > @@ -2524,48 +2522,29 @@ static int virtnet_get_phys_port_name(struct net_device *dev, char *buf, > return 0; > } > > -static netdev_features_t virtnet_fix_features(struct net_device *netdev, > - netdev_features_t features) > -{ > - /* If Rx checksum is disabled, LRO should also be disabled. */ > - if (!(features & NETIF_F_RXCSUM)) > - features &= ~NETIF_F_LRO; > - > - return features; > -} > - > static int virtnet_set_features(struct net_device *dev, > netdev_features_t features) > { > struct virtnet_info *vi = netdev_priv(dev); > - u64 offloads = vi->guest_offloads; > + u64 offloads; > int err; > > - /* Don't allow configuration while XDP is active. */ > - if (vi->xdp_queue_pairs) > - return -EBUSY; > - > if ((dev->features ^ features) & NETIF_F_LRO) { > + if (vi->xdp_queue_pairs) > + return -EBUSY; > + > if (features & NETIF_F_LRO) > - offloads |= GUEST_OFFLOAD_LRO_MASK & > - vi->guest_offloads_capable; > + offloads = vi->guest_offloads_capable; > else > - offloads &= ~GUEST_OFFLOAD_LRO_MASK; > + offloads = vi->guest_offloads_capable & > + ~GUEST_OFFLOAD_LRO_MASK; > + > + err = virtnet_set_guest_offloads(vi, offloads); > + if (err) > + return err; > + vi->guest_offloads = offloads; > } > > - if ((dev->features ^ features) & NETIF_F_RXCSUM) { > - if (features & NETIF_F_RXCSUM) > - offloads |= GUEST_OFFLOAD_CSUM_MASK & > - vi->guest_offloads_capable; > - else > - offloads &= ~GUEST_OFFLOAD_CSUM_MASK; > - } > - > - err = virtnet_set_guest_offloads(vi, offloads); > - if (err) > - return err; > - > - vi->guest_offloads = offloads; > return 0; > } > > @@ -2584,7 +2563,6 @@ static const struct net_device_ops virtnet_netdev = { > .ndo_features_check = passthru_features_check, > .ndo_get_phys_port_name = virtnet_get_phys_port_name, > .ndo_set_features = virtnet_set_features, > - .ndo_fix_features = virtnet_fix_features, > }; > > static void virtnet_config_changed_work(struct work_struct *work) > @@ -3035,10 +3013,8 @@ static int virtnet_probe(struct virtio_device *vdev) > if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) || > virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6)) > dev->features |= NETIF_F_LRO; > - if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS)) { > - dev->hw_features |= NETIF_F_RXCSUM; > + if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS)) > dev->hw_features |= NETIF_F_LRO; > - } > > dev->vlan_features = dev->features; >