kernel/linux.git/net/openvswitch/vport.c, branch v6.18.21

net: openvswitch: fix data race in ovs_vport_get_upcall_stats

2026-01-30T09:32:21+00:00

[ Upstream commit cc4816bdb08639e5cd9acb295a02d6f0f09736b4 ] In ovs_vport_get_upcall_stats(), some statistics protected by u64_stats_sync, are read and accumulated in ignorance of possible u64_stats_fetch_retry() events. These statistics are already accumulated by u64_stats_inc(). Fix this by reading them into temporary variables first. Fixes: 1933ea365aa7 ("net: openvswitch: Add support to count upcall packets") Signed-off-by: David Yang Acked-by: Ilya Maximets Reviewed-by: Eric Dumazet Reviewed-by: Aaron Conole Link: https://patch.msgid.link/20260121072932.2360971-1-mmyangfl@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net: openvswitch: allow providing upcall pid for the 'execute' command

2025-07-07T21:30:39+00:00

When a packet enters OVS datapath and there is no flow to handle it, packet goes to userspace through a MISS upcall. With per-CPU upcall dispatch mechanism, we're using the current CPU id to select the Netlink PID on which to send this packet. This allows us to send packets from the same traffic flow through the same handler. The handler will process the packet, install required flow into the kernel and re-inject the original packet via OVS_PACKET_CMD_EXECUTE. While handling OVS_PACKET_CMD_EXECUTE, however, we may hit a recirculation action that will pass the (likely modified) packet through the flow lookup again. And if the flow is not found, the packet will be sent to userspace again through another MISS upcall. However, the handler thread in userspace is likely running on a different CPU core, and the OVS_PACKET_CMD_EXECUTE request is handled in the syscall context of that thread. So, when the time comes to send the packet through another upcall, the per-CPU dispatch will choose a different Netlink PID, and this packet will end up processed by a different handler thread on a different CPU. The process continues as long as there are new recirculations, each time the packet goes to a different handler thread before it is sent out of the OVS datapath to the destination port. In real setups the number of recirculations can go up to 4 or 5, sometimes more. There is always a chance to re-order packets while processing upcalls, because userspace will first install the flow and then re-inject the original packet. So, there is a race window when the flow is already installed and the second packet can match it and be forwarded to the destination before the first packet is re-injected. But the fact that packets are going through multiple upcalls handled by different userspace threads makes the reordering noticeably more likely, because we not only have a race between the kernel and a userspace handler (which is hard to avoid), but also between multiple userspace handlers. For example, let's assume that 10 packets got enqueued through a MISS upcall for handler-1, it will start processing them, will install the flow into the kernel and start re-injecting packets back, from where they will go through another MISS to handler-2. Handler-2 will install the flow into the kernel and start re-injecting the packets, while handler-1 continues to re-inject the last of the 10 packets, they will hit the flow installed by handler-2 and be forwarded without going to the handler-2, while handler-2 still re-injects the first of these 10 packets. Given multiple recirculations and misses, these 10 packets may end up completely mixed up on the output from the datapath. Let's allow userspace to specify on which Netlink PID the packets should be upcalled while processing OVS_PACKET_CMD_EXECUTE. This makes it possible to ensure that all the packets are processed by the same handler thread in the userspace even with them being upcalled multiple times in the process. Packets will remain in order since they will be enqueued to the same socket and re-injected in the same order. This doesn't eliminate re-ordering as stated above, since we still have a race between kernel and the userspace thread, but it allows to eliminate races between multiple userspace threads. Userspace knows the PID of the socket on which the original upcall is received, so there is no need to send it up from the kernel. Solution requires storing the value somewhere for the duration of the packet processing. There are two potential places for this: our skb extension or the per-CPU storage. It's not clear which is better, so just following currently used scheme of storing this kind of things along the skb. We still have a decent amount of space in the cb. Signed-off-by: Ilya Maximets Acked-by: Flavio Leitner Acked-by: Eelco Chaudron Acked-by: Aaron Conole Link: https://patch.msgid.link/20250702155043.2331772-1-i.maximets@ovn.org Signed-off-by: Jakub Kicinski

net: openvswitch: store sampling probability in cb.

2024-07-06T00:45:47+00:00

When a packet sample is observed, the sampling rate that was used is important to estimate the real frequency of such event. Store the probability of the parent sample action in the skb's cb area and use it in psample action to pass it down to psample module. Reviewed-by: Aaron Conole Acked-by: Eelco Chaudron Reviewed-by: Ilya Maximets Signed-off-by: Adrian Moreno Link: https://patch.msgid.link/20240704085710.353845-7-amorenoz@redhat.com Signed-off-by: Jakub Kicinski

net: openvswitch: fix upcall counter access before allocation

2023-06-07T11:25:05+00:00

Currently, the per cpu upcall counters are allocated after the vport is created and inserted into the system. This could lead to the datapath accessing the counters before they are allocated resulting in a kernel Oops. Here is an example: PID: 59693 TASK: ffff0005f4f51500 CPU: 0 COMMAND: "ovs-vswitchd" #0 [ffff80000a39b5b0] __switch_to at ffffb70f0629f2f4 #1 [ffff80000a39b5d0] __schedule at ffffb70f0629f5cc #2 [ffff80000a39b650] preempt_schedule_common at ffffb70f0629fa60 #3 [ffff80000a39b670] dynamic_might_resched at ffffb70f0629fb58 #4 [ffff80000a39b680] mutex_lock_killable at ffffb70f062a1388 #5 [ffff80000a39b6a0] pcpu_alloc at ffffb70f0594460c #6 [ffff80000a39b750] __alloc_percpu_gfp at ffffb70f05944e68 #7 [ffff80000a39b760] ovs_vport_cmd_new at ffffb70ee6961b90 [openvswitch] ... PID: 58682 TASK: ffff0005b2f0bf00 CPU: 0 COMMAND: "kworker/0:3" #0 [ffff80000a5d2f40] machine_kexec at ffffb70f056a0758 #1 [ffff80000a5d2f70] __crash_kexec at ffffb70f057e2994 #2 [ffff80000a5d3100] crash_kexec at ffffb70f057e2ad8 #3 [ffff80000a5d3120] die at ffffb70f0628234c #4 [ffff80000a5d31e0] die_kernel_fault at ffffb70f062828a8 #5 [ffff80000a5d3210] __do_kernel_fault at ffffb70f056a31f4 #6 [ffff80000a5d3240] do_bad_area at ffffb70f056a32a4 #7 [ffff80000a5d3260] do_translation_fault at ffffb70f062a9710 #8 [ffff80000a5d3270] do_mem_abort at ffffb70f056a2f74 #9 [ffff80000a5d32a0] el1_abort at ffffb70f06297dac #10 [ffff80000a5d32d0] el1h_64_sync_handler at ffffb70f06299b24 #11 [ffff80000a5d3410] el1h_64_sync at ffffb70f056812dc #12 [ffff80000a5d3430] ovs_dp_upcall at ffffb70ee6963c84 [openvswitch] #13 [ffff80000a5d3470] ovs_dp_process_packet at ffffb70ee6963fdc [openvswitch] #14 [ffff80000a5d34f0] ovs_vport_receive at ffffb70ee6972c78 [openvswitch] #15 [ffff80000a5d36f0] netdev_port_receive at ffffb70ee6973948 [openvswitch] #16 [ffff80000a5d3720] netdev_frame_hook at ffffb70ee6973a28 [openvswitch] #17 [ffff80000a5d3730] __netif_receive_skb_core.constprop.0 at ffffb70f06079f90 We moved the per cpu upcall counter allocation to the existing vport alloc and free functions to solve this. Fixes: 95637d91fefd ("net: openvswitch: release vport resources on failure") Fixes: 1933ea365aa7 ("net: openvswitch: Add support to count upcall packets") Signed-off-by: Eelco Chaudron Reviewed-by: Simon Horman Acked-by: Aaron Conole Signed-off-by: David S. Miller

net: openvswitch: Add support to count upcall packets

2022-12-09T10:43:46+00:00

Add support to count upall packets, when kmod of openvswitch upcall to count the number of packets for upcall succeed and failed, which is a better way to see how many packets upcalled on every interfaces. Signed-off-by: wangchuanlei Acked-by: Eelco Chaudron Signed-off-by: David S. Miller

net: Add skb_clear_tstamp() to keep the mono delivery_time

2022-03-03T14:38:48+00:00

Right now, skb->tstamp is reset to 0 whenever the skb is forwarded. If skb->tstamp has the mono delivery_time, clearing it can hurt the performance when it finally transmits out to fq@phy-dev. The earlier patch added a skb->mono_delivery_time bit to flag the skb->tstamp carrying the mono delivery_time. This patch adds skb_clear_tstamp() helper which keeps the mono delivery_time and clears everything else. The delivery_time clearing will be postponed until the stack knows the skb will be delivered locally. It will be done in a latter patch. Signed-off-by: Martin KaFai Lau Signed-off-by: David S. Miller

ovs: clear skb->tstamp in forwarding path

2021-08-18T10:31:13+00:00

fq qdisc requires tstamp to be cleared in the forwarding path. Now ovs doesn't clear skb->tstamp. We encountered a problem with linux version 5.4.56 and ovs version 2.14.1, and packets failed to dequeue from qdisc when fq qdisc was attached to ovs port. Fixes: fb420d5d91c1 ("tcp/fq: move back to CLOCK_MONOTONIC") Signed-off-by: kaixi.fan Signed-off-by: xiexiaohui Reviewed-by: Cong Wang Signed-off-by: David S. Miller

openvswitch: Warn over-mtu packets only if iface is UP.

2021-03-16T23:28:30+00:00

It is not unusual to have the bridge port down. Sometimes it has the old MTU, which is fine since it's not being used. However, the kernel spams the log with a warning message when a packet is going to be sent over such port. Fix that by warning only if the interface is UP. Signed-off-by: Flavio Leitner Signed-off-by: David S. Miller

net: openvswitch: Fix kerneldoc warnings

2020-10-30T18:39:43+00:00

net/openvswitch/flow.c:303: warning: Function parameter or member 'key_vh' not described in 'parse_vlan_tag' net/openvswitch/flow.c:303: warning: Function parameter or member 'skb' not described in 'parse_vlan_tag' net/openvswitch/flow.c:303: warning: Function parameter or member 'untag_vlan' not described in 'parse_vlan_tag' net/openvswitch/vport.c:122: warning: Function parameter or member 'parms' not described in 'ovs_vport_alloc' Signed-off-by: Andrew Lunn Link: https://lore.kernel.org/r/20201028004849.930094-1-andrew@lunn.ch Signed-off-by: Jakub Kicinski

net: openvswitch: improve the coding style

2020-09-01T18:42:15+00:00

Not change the logic, just improve the coding style. Cc: Pravin B Shelar Signed-off-by: Tonghao Zhang Acked-by: Pravin B Shelar Signed-off-by: David S. Miller