kernel/git/stable/linux.git/net/openvswitch/datapath.h, branch linux-5.15.y

openvswitch: Fix CT limit teardown use-after-free

2026-09-14T11:20:15+00:00

[ Upstream commit 403f96c32c9e24600093d7d0c61c17daeedca957 ] Packet processing uses CT limit state under RCU, while netns teardown frees that state under ovs_mutex. The CT limit pointer was neither removed from readers nor protected by a grace period, allowing packet processing to dereference the freed state. An unprivileged user can trigger this bug from a user and network namespace, causing a slab-use-after-free in ovs_ct_execute() when the netns is torn down. Publish the CT limit pointer through RCU, remove it before teardown, and wait for readers before freeing its contents. Keep ovs_mutex around individual CT limit updates, and use the RCU read-side lock while GET traverses the RCU-protected limit lists. Netns teardown detaches the RCU-protected CT limit state in the pernet .pre_exit callback while holding ovs_mutex. The pernet core guarantees an RCU grace period between the .pre_exit and .exit callbacks, so the .exit callback completes the teardown without adding any extra synchronization. The netlink command handlers do not need NULL checks because the userspace netlink socket holds an active reference to its network namespace while a request is processed. The per-netns exit path therefore cannot run concurrently with SET, DEL, or GET for that socket's namespace. Fixes: 11efd5cb04a1 ("openvswitch: Support conntrack zone limit") Cc: stable@vger.kernel.org Reported-by: Vega Link: https://lore.kernel.org/all/cover.1784711445.git.xuyuqiabc@gmail.com Co-developed-by: Nan Li Signed-off-by: Nan Li Signed-off-by: Yuqi Xu Reviewed-by: Ren Wei Reviewed-by: Ilya Maximets Link: https://patch.msgid.link/288fbd5459d92b9dd0dcc6faf625f04819161ff3.1787280296.git.xuyuqiabc@gmail.com Signed-off-by: Jakub Kicinski [ 7.0+ uses kmalloc_obj[s] while older versions use kmalloc[_array] 6.12+ doesn't have a 'family' argument in nf_conncount_init/destroy ] Signed-off-by: Ilya Maximets Signed-off-by: Sasha Levin

net: openvswitch: fix kernel-doc warnings in internal headers

2026-09-14T11:20:15+00:00

[ Upstream commit 6bb0dcb3d321c14be7ca33b71a149034d6a2cde8 ] Some field descriptions were missing, some were not very accurate. Not touching the uAPI header or .c files for now. Formatting of those comments isn't great in general, but at least they are not missing anything now. Before: $ ./scripts/kernel-doc -none -Wall net/openvswitch/*.h 2>&1 | wc -l 16 After: $ ./scripts/kernel-doc -none -Wall net/openvswitch/*.h 2>&1 | wc -l 0 Signed-off-by: Ilya Maximets Acked-by: Eelco Chaudron Reviewed-by: Aaron Conole Link: https://patch.msgid.link/20250320224431.252489-1-i.maximets@ovn.org Signed-off-by: Jakub Kicinski [ struct vport_upcall_stats_percpu doesn't exist in 6.2 and earlier ] Signed-off-by: Ilya Maximets Signed-off-by: Sasha Levin

openvswitch: fix GSO userspace truncation underflow

2026-08-19T15:14:05+00:00

[ Upstream commit 4032f8ed10fcb84d41c508dfb04be96589f78dfe ] OVS_ACTION_ATTR_TRUNC currently stores a delta from the original skb length in OVS_CB(skb)->cutlen. When a later userspace action segments a GSO skb, queue_gso_packets() reuses that delta for each smaller segment. A segment can then reach queue_userspace_packet() with cutlen greater than skb->len, underflowing the length passed to skb_zerocopy(). Store the maximum preserved length instead and bound each consumer against the current skb length. Use U32_MAX as the no-truncation sentinel so the value remains valid if skb geometry changes before a consumer handles it. Fixes: f2a4d086ed4c ("openvswitch: Add packet truncation support.") Cc: stable@vger.kernel.org Assisted-by: Codex:gpt-5.5 Signed-off-by: Kyle Zeng Reviewed-by: Ilya Maximets Reviewed-by: Aaron Conole Link: https://patch.msgid.link/20260707221635.27489-1-kylebot@openai.com Signed-off-by: Paolo Abeni [5.15.y supports neither OVS_ACTION_ATTR_PSAMPLE nor OVS drop reasons] Signed-off-by: Ilya Maximets Signed-off-by: Sasha Levin

openvswitch: Introduce per-cpu upcall dispatch

2021-07-16T18:06:33+00:00

The Open vSwitch kernel module uses the upcall mechanism to send packets from kernel space to user space when it misses in the kernel space flow table. The upcall sends packets via a Netlink socket. Currently, a Netlink socket is created for every vport. In this way, there is a 1:1 mapping between a vport and a Netlink socket. When a packet is received by a vport, if it needs to be sent to user space, it is sent via the corresponding Netlink socket. This mechanism, with various iterations of the corresponding user space code, has seen some limitations and issues: * On systems with a large number of vports, there is a correspondingly large number of Netlink sockets which can limit scaling. (https://bugzilla.redhat.com/show_bug.cgi?id=1526306) * Packet reordering on upcalls. (https://bugzilla.redhat.com/show_bug.cgi?id=1844576) * A thundering herd issue. (https://bugzilla.redhat.com/show_bug.cgi?id=1834444) This patch introduces an alternative, feature-negotiated, upcall mode using a per-cpu dispatch rather than a per-vport dispatch. In this mode, the Netlink socket to be used for the upcall is selected based on the CPU of the thread that is executing the upcall. In this way, it resolves the issues above as: a) The number of Netlink sockets scales with the number of CPUs rather than the number of vports. b) Ordering per-flow is maintained as packets are distributed to CPUs based on mechanisms such as RSS and flows are distributed to a single user space thread. c) Packets from a flow can only wake up one user space thread. The corresponding user space code can be found at: https://mail.openvswitch.org/pipermail/ovs-dev/2021-July/385139.html Bugzilla: https://bugzilla.redhat.com/1844576 Signed-off-by: Mark Gray Acked-by: Flavio Leitner Acked-by: Pravin B Shelar Signed-off-by: David S. Miller

net: openvswitch: add masks cache hit counter

2020-08-03T22:17:48+00:00

Add a counter that counts the number of masks cache hits, and export it through the megaflow netlink statistics. Reviewed-by: Paolo Abeni Reviewed-by: Tonghao Zhang Signed-off-by: Eelco Chaudron Signed-off-by: David S. Miller

net: openvswitch: fixes potential deadlock in dp cleanup code

2020-07-24T23:58:38+00:00

The previous patch introduced a deadlock, this patch fixes it by making sure the work is canceled without holding the global ovs lock. This is done by moving the reorder processing one layer up to the netns level. Fixes: eac87c413bf9 ("net: openvswitch: reorder masks array based on usage") Reported-by: syzbot+2c4ff3614695f75ce26c@syzkaller.appspotmail.com Reported-by: syzbot+bad6507e5db05017b008@syzkaller.appspotmail.com Reviewed-by: Paolo Signed-off-by: Eelco Chaudron Signed-off-by: David S. Miller

net: openvswitch: reorder masks array based on usage

2020-07-17T17:36:50+00:00

This patch reorders the masks array every 4 seconds based on their usage count. This greatly reduces the masks per packet hit, and hence the overall performance. Especially in the OVS/OVN case for OpenShift. Here are some results from the OVS/OVN OpenShift test, which use 8 pods, each pod having 512 uperf connections, each connection sends a 64-byte request and gets a 1024-byte response (TCP). All uperf clients are on 1 worker node while all uperf servers are on the other worker node. Kernel without this patch : 7.71 Gbps Kernel with this patch applied: 14.52 Gbps We also run some tests to verify the rebalance activity does not lower the flow insertion rate, which does not. Signed-off-by: Eelco Chaudron Tested-by: Andrew Theurer Reviewed-by: Paolo Abeni Signed-off-by: David S. Miller

net: openvswitch: expand the meters supported number

2020-04-24T01:26:11+00:00

In kernel datapath of Open vSwitch, there are only 1024 buckets of meter in one datapath. If installing more than 1024 (e.g. 8192) meters, it may lead to the performance drop. But in some case, for example, Open vSwitch used as edge gateway, there should be 20K at least, where meters used for IP address bandwidth limitation. [Open vSwitch userspace datapath has this issue too.] For more scalable meter, this patch use meter array instead of hash tables, and expand/shrink the array when necessary. So we can install more meters than before in the datapath. Introducing the struct *dp_meter_instance, it's easy to expand meter though changing the *ti point in the struct *dp_meter_table. Cc: Pravin B Shelar Cc: Andy Zhou Signed-off-by: Tonghao Zhang Acked-by: Pravin B Shelar Signed-off-by: David S. Miller

net: openvswitch: add hash info to upcall

2019-11-15T01:29:46+00:00

When using the kernel datapath, the upcall don't include skb hash info relatived. That will introduce some problem, because the hash of skb is important in kernel stack. For example, VXLAN module uses it to select UDP src port. The tx queue selection may also use the hash in stack. Hash is computed in different ways. Hash is random for a TCP socket, and hash may be computed in hardware, or software stack. Recalculation hash is not easy. Hash of TCP socket is computed: tcp_v4_connect -> sk_set_txhash (is random) __tcp_transmit_skb -> skb_set_hash_from_sk There will be one upcall, without information of skb hash, to ovs-vswitchd, for the first packet of a TCP session. The rest packets will be processed in Open vSwitch modules, hash kept. If this tcp session is forward to VXLAN module, then the UDP src port of first tcp packet is different from rest packets. TCP packets may come from the host or dockers, to Open vSwitch. To fix it, we store the hash info to upcall, and restore hash when packets sent back. +---------------+ +-------------------------+ | Docker/VMs | | ovs-vswitchd | +----+----------+ +-+--------------------+--+ | ^ | | | | | | upcall v restore packet hash (not recalculate) | +-+--------------------+--+ | tap netdev | | vxlan module +---------------> +--> Open vSwitch ko +--> or internal type | | +-------------------------+ Reported-at: https://mail.openvswitch.org/pipermail/ovs-dev/2019-October/364062.html Signed-off-by: Tonghao Zhang Acked-by: Pravin B Shelar Signed-off-by: David S. Miller

net: openvswitch: Set OvS recirc_id from tc chain index

2019-09-06T12:59:18+00:00

Offloaded OvS datapath rules are translated one to one to tc rules, for example the following simplified OvS rule: recirc_id(0),in_port(dev1),eth_type(0x0800),ct_state(-trk) actions:ct(),recirc(2) Will be translated to the following tc rule: $ tc filter add dev dev1 ingress \ prio 1 chain 0 proto ip \ flower tcp ct_state -trk \ action ct pipe \ action goto chain 2 Received packets will first travel though tc, and if they aren't stolen by it, like in the above rule, they will continue to OvS datapath. Since we already did some actions (action ct in this case) which might modify the packets, and updated action stats, we would like to continue the proccessing with the correct recirc_id in OvS (here recirc_id(2)) where we left off. To support this, introduce a new skb extension for tc, which will be used for translating tc chain to ovs recirc_id to handle these miss cases. Last tc chain index will be set by tc goto chain action and read by OvS datapath. Signed-off-by: Paul Blakey Signed-off-by: Vlad Buslov Acked-by: Jiri Pirko Acked-by: Pravin B Shelar Signed-off-by: David S. Miller