kernel/linux.git/drivers/net/veth.c, branch v5.15.208

net: veth: do not manipulate GRO when using XDP

2024-03-26T22:21:35+00:00

[ Upstream commit d7db7775ea2e31502d46427f5efd385afc4ff1eb ] Commit d3256efd8e8b ("veth: allow enabling NAPI even without XDP") tried to fix the fact that GRO was not possible without XDP, because veth did not use NAPI without XDP. However, it also introduced the behaviour that GRO is always enabled, when XDP is enabled. While it might be desired for most cases, it is confusing for the user at best as the GRO flag suddenly changes, when an XDP program is attached. It also introduces some complexities in state management as was partially addressed in commit fe9f801355f0 ("net: veth: clear GRO when clearing XDP even when down"). But the biggest problem is that it is not possible to disable GRO at all, when an XDP program is attached, which might be needed for some use cases. Fix this by not touching the GRO flag on XDP enable/disable as the code already supports switching to NAPI if either GRO or XDP is requested. Link: https://lore.kernel.org/lkml/20240311124015.38106-1-ignat@cloudflare.com/ Fixes: d3256efd8e8b ("veth: allow enabling NAPI even without XDP") Fixes: fe9f801355f0 ("net: veth: clear GRO when clearing XDP even when down") Signed-off-by: Ignat Korchagin Reviewed-by: Toke Høiland-Jørgensen Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

veth: try harder when allocating queue memory

2024-03-06T14:38:45+00:00

[ Upstream commit 1ce7d306ea63f3e379557c79abd88052e0483813 ] struct veth_rq is pretty large, 832B total without debug options enabled. Since commit under Fixes we try to pre-allocate enough queues for every possible CPU. Miao Wang reports that this may lead to order-5 allocations which will fail in production. Let the allocation fallback to vmalloc() and try harder. These are the same flags we pass to netdev queue allocation. Reported-and-tested-by: Miao Wang Fixes: 9d3684c24a52 ("veth: create by default nr_possible_cpus queues") Link: https://lore.kernel.org/all/5F52CAE2-2FB7-4712-95F1-3312FBBFA8DD@gmail.com/ Signed-off-by: Jakub Kicinski Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20240223235908.693010-1-kuba@kernel.org Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net: enable memcg accounting for veth queues

2024-03-06T14:38:45+00:00

[ Upstream commit 961c6136359eef38a8c023d02028fdcd123f02a6 ] veth netdevice defines own rx queues and allocates array containing up to 4095 ~750-bytes-long 'struct veth_rq' elements. Such allocation is quite huge and should be accounted to memcg. Signed-off-by: Vasily Averin Signed-off-by: David S. Miller Stable-dep-of: 1ce7d306ea63 ("veth: try harder when allocating queue memory") Signed-off-by: Sasha Levin

net: veth: clear GRO when clearing XDP even when down

2024-03-06T14:38:45+00:00

[ Upstream commit fe9f801355f0b47668419f30f1fac1cf4539e736 ] veth sets NETIF_F_GRO automatically when XDP is enabled, because both features use the same NAPI machinery. The logic to clear NETIF_F_GRO sits in veth_disable_xdp() which is called both on ndo_stop and when XDP is turned off. To avoid the flag from being cleared when the device is brought down, the clearing is skipped when IFF_UP is not set. Bringing the device down should indeed not modify its features. Unfortunately, this means that clearing is also skipped when XDP is disabled _while_ the device is down. And there's nothing on the open path to bring the device features back into sync. IOW if user enables XDP, disables it and then brings the device up we'll end up with a stray GRO flag set but no NAPI instances. We don't depend on the GRO flag on the datapath, so the datapath won't crash. We will crash (or hang), however, next time features are sync'ed (either by user via ethtool or peer changing its config). The GRO flag will go away, and veth will try to disable the NAPIs. But the open path never created them since XDP was off, the GRO flag was a stray. If NAPI was initialized before we'll hang in napi_disable(). If it never was we'll crash trying to stop uninitialized hrtimer. Move the GRO flag updates to the XDP enable / disable paths, instead of mixing them with the ndo_open / ndo_close paths. Fixes: d3256efd8e8b ("veth: allow enabling NAPI even without XDP") Reported-by: Thomas Gleixner Reported-by: syzbot+039399a9b96297ddedca@syzkaller.appspotmail.com Signed-off-by: Jakub Kicinski Reviewed-by: Toke Høiland-Jørgensen Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

veth: Fixing transmit return status for dropped packets

2023-09-19T10:22:58+00:00

[ Upstream commit 151e887d8ff97e2e42110ffa1fb1e6a2128fb364 ] The veth_xmit function returns NETDEV_TX_OK even when packets are dropped. This behavior leads to incorrect calculations of statistics counts, as well as things like txq->trans_start updates. Fixes: e314dbdc1c0d ("[NET]: Virtual ethernet device driver.") Signed-off-by: Liang Chen Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: validate veth and vxcan peer ifindexes

2023-08-30T14:18:14+00:00

[ Upstream commit f534f6581ec084fe94d6759f7672bd009794b07e ] veth and vxcan need to make sure the ifindexes of the peer are not negative, core does not validate this. Using iproute2 with user-space-level checking removed: Before: # ./ip link add index 10 type veth peer index -1 # ip link show 1: lo: mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: enp1s0: mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000 link/ether 52:54:00:74:b2:03 brd ff:ff:ff:ff:ff:ff 10: veth1@veth0: mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 8a:90:ff:57:6d:5d brd ff:ff:ff:ff:ff:ff -1: veth0@veth1: mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether ae:ed:18:e6:fa:7f brd ff:ff:ff:ff:ff:ff Now: $ ./ip link add index 10 type veth peer index -1 Error: ifindex can't be negative. This problem surfaced in net-next because an explicit WARN() was added, the root cause is older. Fixes: e6f8f1a739b6 ("veth: Allow to create peer link with given ifindex") Fixes: a8f820a380a2 ("can: add Virtual CAN Tunnel driver (vxcan)") Reported-by: syzbot+5ba06978f34abb058571@syzkaller.appspotmail.com Signed-off-by: Jakub Kicinski Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

veth: Fix race with AF_XDP exposing old or uninitialized descriptors

2023-01-12T10:59:09+00:00

[ Upstream commit fa349e396e4886d742fd6501c599ec627ef1353b ] When AF_XDP is used on on a veth interface the RX ring is updated in two steps. veth_xdp_rcv() removes packet descriptors from the FILL ring fills them and places them in the RX ring updating the cached_prod pointer. Later xdp_do_flush() syncs the RX ring prod pointer with the cached_prod pointer allowing user-space to see the recently filled in descriptors. The rings are intended to be SPSC, however the existing order in veth_poll allows the xdp_do_flush() to run concurrently with another CPU creating a race condition that allows user-space to see old or uninitialized descriptors in the RX ring. This bug has been observed in production systems. To summarize, we are expecting this ordering: CPU 0 __xsk_rcv_zc() CPU 0 __xsk_map_flush() CPU 2 __xsk_rcv_zc() CPU 2 __xsk_map_flush() But we are seeing this order: CPU 0 __xsk_rcv_zc() CPU 2 __xsk_rcv_zc() CPU 0 __xsk_map_flush() CPU 2 __xsk_map_flush() This occurs because we rely on NAPI to ensure that only one napi_poll handler is running at a time for the given veth receive queue. napi_schedule_prep() will prevent multiple instances from getting scheduled. However calling napi_complete_done() signals that this napi_poll is complete and allows subsequent calls to napi_schedule_prep() and __napi_schedule() to succeed in scheduling a concurrent napi_poll before the xdp_do_flush() has been called. For the veth driver a concurrent call to napi_schedule_prep() and __napi_schedule() can occur on a different CPU because the veth xmit path can additionally schedule a napi_poll creating the race. The fix as suggested by Magnus Karlsson, is to simply move the xdp_do_flush() call before napi_complete_done(). This syncs the producer ring pointers before another instance of napi_poll can be scheduled on another CPU. It will also slightly improve performance by moving the flush closer to when the descriptors were placed in the RX ring. Fixes: d1396004dd86 ("veth: Add XDP TX and REDIRECT") Suggested-by: Magnus Karlsson Signed-off-by: Shawn Bohrer Link: https://lore.kernel.org/r/20221220185903.1105011-1-sbohrer@cloudflare.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

veth: Ensure eth header is in skb's linear part

2022-04-20T07:34:10+00:00

[ Upstream commit 726e2c5929de841fdcef4e2bf995680688ae1b87 ] After feeding a decapsulated packet to a veth device with act_mirred, skb_headlen() may be 0. But veth_xmit() calls __dev_forward_skb(), which expects at least ETH_HLEN byte of linear data (as __dev_forward_skb2() calls eth_type_trans(), which pulls ETH_HLEN bytes unconditionally). Use pskb_may_pull() to ensure veth_xmit() respects this constraint. kernel BUG at include/linux/skbuff.h:2328! RIP: 0010:eth_type_trans+0xcf/0x140 Call Trace: __dev_forward_skb2+0xe3/0x160 veth_xmit+0x6e/0x250 [veth] dev_hard_start_xmit+0xc7/0x200 __dev_queue_xmit+0x47f/0x520 ? skb_ensure_writable+0x85/0xa0 ? skb_mpls_pop+0x98/0x1c0 tcf_mirred_act+0x442/0x47e [act_mirred] tcf_action_exec+0x86/0x140 fl_classify+0x1d8/0x1e0 [cls_flower] ? dma_pte_clear_level+0x129/0x1a0 ? dma_pte_clear_level+0x129/0x1a0 ? prb_fill_curr_block+0x2f/0xc0 ? skb_copy_bits+0x11a/0x220 __tcf_classify+0x58/0x110 tcf_classify_ingress+0x6b/0x140 __netif_receive_skb_core.constprop.0+0x47d/0xfd0 ? __iommu_dma_unmap_swiotlb+0x44/0x90 __netif_receive_skb_one_core+0x3d/0xa0 netif_receive_skb+0x116/0x170 be_process_rx+0x22f/0x330 [be2net] be_poll+0x13c/0x370 [be2net] __napi_poll+0x2a/0x170 net_rx_action+0x22f/0x2f0 __do_softirq+0xca/0x2a8 __irq_exit_rcu+0xc1/0xe0 common_interrupt+0x83/0xa0 Fixes: e314dbdc1c0d ("[NET]: Virtual ethernet device driver.") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

veth: fix races around rq->rx_notify_masked

2022-02-16T11:56:30+00:00

[ Upstream commit 68468d8c4cd4222a4ca1f185ab5a1c14480d078c ] veth being NETIF_F_LLTX enabled, we need to be more careful whenever we read/write rq->rx_notify_masked. BUG: KCSAN: data-race in veth_xmit / veth_xmit write to 0xffff888133d9a9f8 of 1 bytes by task 23552 on cpu 0: __veth_xdp_flush drivers/net/veth.c:269 [inline] veth_xmit+0x307/0x470 drivers/net/veth.c:350 __netdev_start_xmit include/linux/netdevice.h:4683 [inline] netdev_start_xmit include/linux/netdevice.h:4697 [inline] xmit_one+0x105/0x2f0 net/core/dev.c:3473 dev_hard_start_xmit net/core/dev.c:3489 [inline] __dev_queue_xmit+0x86d/0xf90 net/core/dev.c:4116 dev_queue_xmit+0x13/0x20 net/core/dev.c:4149 br_dev_queue_push_xmit+0x3ce/0x430 net/bridge/br_forward.c:53 NF_HOOK include/linux/netfilter.h:307 [inline] br_forward_finish net/bridge/br_forward.c:66 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] __br_forward+0x2e4/0x400 net/bridge/br_forward.c:115 br_flood+0x521/0x5c0 net/bridge/br_forward.c:242 br_dev_xmit+0x8b6/0x960 __netdev_start_xmit include/linux/netdevice.h:4683 [inline] netdev_start_xmit include/linux/netdevice.h:4697 [inline] xmit_one+0x105/0x2f0 net/core/dev.c:3473 dev_hard_start_xmit net/core/dev.c:3489 [inline] __dev_queue_xmit+0x86d/0xf90 net/core/dev.c:4116 dev_queue_xmit+0x13/0x20 net/core/dev.c:4149 neigh_hh_output include/net/neighbour.h:525 [inline] neigh_output include/net/neighbour.h:539 [inline] ip_finish_output2+0x6f8/0xb70 net/ipv4/ip_output.c:228 ip_finish_output+0xfb/0x240 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_output+0xf3/0x1a0 net/ipv4/ip_output.c:430 dst_output include/net/dst.h:451 [inline] ip_local_out net/ipv4/ip_output.c:126 [inline] ip_send_skb+0x6e/0xe0 net/ipv4/ip_output.c:1570 udp_send_skb+0x641/0x880 net/ipv4/udp.c:967 udp_sendmsg+0x12ea/0x14c0 net/ipv4/udp.c:1254 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:819 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg net/socket.c:725 [inline] ____sys_sendmsg+0x39a/0x510 net/socket.c:2413 ___sys_sendmsg net/socket.c:2467 [inline] __sys_sendmmsg+0x267/0x4c0 net/socket.c:2553 __do_sys_sendmmsg net/socket.c:2582 [inline] __se_sys_sendmmsg net/socket.c:2579 [inline] __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2579 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff888133d9a9f8 of 1 bytes by task 23563 on cpu 1: __veth_xdp_flush drivers/net/veth.c:268 [inline] veth_xmit+0x2d6/0x470 drivers/net/veth.c:350 __netdev_start_xmit include/linux/netdevice.h:4683 [inline] netdev_start_xmit include/linux/netdevice.h:4697 [inline] xmit_one+0x105/0x2f0 net/core/dev.c:3473 dev_hard_start_xmit net/core/dev.c:3489 [inline] __dev_queue_xmit+0x86d/0xf90 net/core/dev.c:4116 dev_queue_xmit+0x13/0x20 net/core/dev.c:4149 br_dev_queue_push_xmit+0x3ce/0x430 net/bridge/br_forward.c:53 NF_HOOK include/linux/netfilter.h:307 [inline] br_forward_finish net/bridge/br_forward.c:66 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] __br_forward+0x2e4/0x400 net/bridge/br_forward.c:115 br_flood+0x521/0x5c0 net/bridge/br_forward.c:242 br_dev_xmit+0x8b6/0x960 __netdev_start_xmit include/linux/netdevice.h:4683 [inline] netdev_start_xmit include/linux/netdevice.h:4697 [inline] xmit_one+0x105/0x2f0 net/core/dev.c:3473 dev_hard_start_xmit net/core/dev.c:3489 [inline] __dev_queue_xmit+0x86d/0xf90 net/core/dev.c:4116 dev_queue_xmit+0x13/0x20 net/core/dev.c:4149 neigh_hh_output include/net/neighbour.h:525 [inline] neigh_output include/net/neighbour.h:539 [inline] ip_finish_output2+0x6f8/0xb70 net/ipv4/ip_output.c:228 ip_finish_output+0xfb/0x240 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_output+0xf3/0x1a0 net/ipv4/ip_output.c:430 dst_output include/net/dst.h:451 [inline] ip_local_out net/ipv4/ip_output.c:126 [inline] ip_send_skb+0x6e/0xe0 net/ipv4/ip_output.c:1570 udp_send_skb+0x641/0x880 net/ipv4/udp.c:967 udp_sendmsg+0x12ea/0x14c0 net/ipv4/udp.c:1254 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:819 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg net/socket.c:725 [inline] ____sys_sendmsg+0x39a/0x510 net/socket.c:2413 ___sys_sendmsg net/socket.c:2467 [inline] __sys_sendmmsg+0x267/0x4c0 net/socket.c:2553 __do_sys_sendmmsg net/socket.c:2582 [inline] __se_sys_sendmmsg net/socket.c:2579 [inline] __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2579 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x00 -> 0x01 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 23563 Comm: syz-executor.5 Not tainted 5.17.0-rc2-syzkaller-00064-gc36c04c2e132 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 948d4f214fde ("veth: Add driver XDP") Signed-off-by: Eric Dumazet Cc: Toshiaki Makita Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

veth: Do not record rx queue hint in veth_xmit

2022-01-16T08:12:44+00:00

commit 710ad98c363a66a0cd8526465426c5c5f8377ee0 upstream. Laurent reported that they have seen a significant amount of TCP retransmissions at high throughput from applications residing in network namespaces talking to the outside world via veths. The drops were seen on the qdisc layer (fq_codel, as per systemd default) of the phys device such as ena or virtio_net due to all traffic hitting a _single_ TX queue _despite_ multi-queue device. (Note that the setup was _not_ using XDP on veths as the issue is generic.) More specifically, after edbea9220251 ("veth: Store queue_mapping independently of XDP prog presence") which made it all the way back to v4.19.184+, skb_record_rx_queue() would set skb->queue_mapping to 1 (given 1 RX and 1 TX queue by default for veths) instead of leaving at 0. This is eventually retained and callbacks like ena_select_queue() will also pick single queue via netdev_core_pick_tx()'s ndo_select_queue() once all the traffic is forwarded to that device via upper stack or other means. Similarly, for others not implementing ndo_select_queue() if XPS is disabled, netdev_pick_tx() might call into the skb_tx_hash() and check for prior skb_rx_queue_recorded() as well. In general, it is a _bad_ idea for virtual devices like veth to mess around with queue selection [by default]. Given dev->real_num_tx_queues is by default 1, the skb->queue_mapping was left untouched, and so prior to edbea9220251 the netdev_core_pick_tx() could do its job upon __dev_queue_xmit() on the phys device. Unbreak this and restore prior behavior by removing the skb_record_rx_queue() from veth_xmit() altogether. If the veth peer has an XDP program attached, then it would return the first RX queue index in xdp_md->rx_queue_index (unless configured in non-default manner). However, this is still better than breaking the generic case. Fixes: edbea9220251 ("veth: Store queue_mapping independently of XDP prog presence") Fixes: 638264dc9022 ("veth: Support per queue XDP ring") Reported-by: Laurent Bernaille Signed-off-by: Daniel Borkmann Cc: Maciej Fijalkowski Cc: Toshiaki Makita Cc: Eric Dumazet Cc: Paolo Abeni Cc: John Fastabend Cc: Willem de Bruijn Acked-by: John Fastabend Reviewed-by: Eric Dumazet Acked-by: Toshiaki Makita Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman