kernel/git/next/linux-next.git/include/net/ip_tunnels.h, branch master

sit: convert configuration to RCU protection

2026-09-11T01:35:34+00:00

Now that SIT parameters are dynamically allocated, convert tunnel->sit_parms to an RCU-protected pointer. Updates in ipip6_tunnel_update() allocate a new parameter block, publish it using rcu_assign_pointer(), and free the old one via kfree_rcu(). We only need to unlink and re-link the tunnel in the hash table if either saddr or daddr changed. When neither address changes, the unhash/re-hash and synchronize_net() can be completely skipped. Readers in ipip6_tunnel_lookup(), ipip6_tunnel_xmit(), ipip6_err(), and ipip6_rcv() now safely dereference tunnel->sit_parms under RCU. Signed-off-by: Eric Dumazet Acked-by: Lorenzo Bianconi Link: https://patch.msgid.link/20260907075846.2913645-9-edumazet@google.com Signed-off-by: Jakub Kicinski

sit: dynamically allocate struct ip_tunnel_parm_kern

2026-09-11T01:35:34+00:00

In preparation for converting SIT configuration parameters to RCU, dynamically allocate struct ip_tunnel_parm_kern as sit_parms in struct ip_tunnel. Signed-off-by: Eric Dumazet Acked-by: Lorenzo Bianconi Link: https://patch.msgid.link/20260907075846.2913645-8-edumazet@google.com Signed-off-by: Jakub Kicinski

sit: convert 6RD configuration to RCU protection

2026-09-11T01:35:33+00:00

In order to allow lockless readers in future patches, convert 'tunnel->ip6rd' to an RCU protected pointer. Updating 6RD configuration via ipip6_tunnel_update_6rd() or ipip6_tunnel_clone_6rd() now allocates a struct ip_tunnel_6rd_parm and uses rcu_assign_pointer() to publish it, freeing the previous parameters with kfree_rcu(). Readers in check_6rd() and only_dnatted() use rcu_dereference() under existing RCU read lock, preventing torn reads on the 128-bit IPv6 prefix. Signed-off-by: Eric Dumazet Acked-by: Lorenzo Bianconi Link: https://patch.msgid.link/20260907075846.2913645-6-edumazet@google.com Signed-off-by: Jakub Kicinski

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2026-08-18T17:42:41+00:00

Merge in late fixes in preparation for the net-next PR. Conflicts: drivers/dpll/dpll_core.c drivers/dpll/dpll_netlink.c 33f016b23a219 ("dpll: fix NULL deref in dpll_device_ops() during teardown race") b1d0c412088e3 ("dpll: add STATE_CONNECTED_OVERRIDE pin capability") https://lore.kernel.org/aoR9YYY2P5--3x0N@sirena.org.uk https://lore.kernel.org/aoR9VmKllVGwmQn_@sirena.org.uk No adjacent changes. Signed-off-by: Jakub Kicinski

net: ip_tunnel: remove unused non-strict __ip_tunnel_change_mtu

2026-08-18T11:27:13+00:00

The last user of this function was the recently removed vport-gre module from openvswitch. Let's drop the function. All other modules use the strict variant. Signed-off-by: Ilya Maximets Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260815001942.1089545-1-i.maximets@ovn.org Signed-off-by: Paolo Abeni

net: cap advertised IP tunnel headroom

2026-08-18T10:42:30+00:00

IP tunnel devices derive their advertised needed_headroom from lower output devices. A stack of user-created devices can make the derived value larger than the 16-bit skb header offsets can represent. Once IP output reserves it, skb head expansion can wrap those offsets. The runtime transmit path already caps a growing needed_headroom at 512. Apply the same cap when tunnel configuration publishes needed_headroom derived from a lower output device. Capping the advertised value is safe: IP tunnel transmit still expands the skb when a packet needs more headroom. A nonsensical stacked configuration can therefore incur an extra reallocation, but it cannot publish an unbounded reservation to upper layers. Fixes: 1a37e412a022 ("net: Use 16bits for *_headers fields of struct skbuff") Cc: stable@vger.kernel.org Reported-by: Vega Signed-off-by: Zhiling Zou Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/ba04a1fd6bfae2377607fad5d8f80f7eb80fd4c4.1786542637.git.zhilinz@nebusec.ai Signed-off-by: Paolo Abeni

net: increase IP_TUNNEL_RECURSION_LIMIT to 5

2026-04-03T22:52:10+00:00

In configurations with multiple tunnel layers and MPLS lwtunnel routing, a single tunnel hop can increment the counter beyond this limit. This causes packets to be dropped with the "Dead loop on virtual device" message even when a routing loop doesn't exist. Increase IP_TUNNEL_RECURSION_LIMIT from 4 to 5 to handle this use-case. Fixes: 6f1a9140ecda ("net: add xmit recursion limit to tunnel xmit functions") Link: https://lore.kernel.org/netdev/88deb91b-ef1b-403c-8eeb-0f971f27e34f@redhat.com/ Signed-off-by: Chris J Arges Link: https://patch.msgid.link/20260402222401.3408368-1-carges@cloudflare.com Signed-off-by: Jakub Kicinski

ip_tunnel: adapt iptunnel_xmit_stats() to NETDEV_PCPU_STAT_DSTATS

2026-03-13T02:24:45+00:00

Blamed commits forgot that vxlan/geneve use udp_tunnel[6]_xmit_skb() which call iptunnel_xmit_stats(). iptunnel_xmit_stats() was assuming tunnels were only using NETDEV_PCPU_STAT_TSTATS. @syncp offset in pcpu_sw_netstats and pcpu_dstats is different. 32bit kernels would either have corruptions or freezes if the syncp sequence was overwritten. This patch also moves pcpu_stat_type closer to dev->{t,d}stats to avoid a potential cache line miss since iptunnel_xmit_stats() needs to read it. Fixes: 6fa6de302246 ("geneve: Handle stats using NETDEV_PCPU_STAT_DSTATS.") Fixes: be226352e8dc ("vxlan: Handle stats using NETDEV_PCPU_STAT_DSTATS.") Signed-off-by: Eric Dumazet Reviewed-by: Guillaume Nault Link: https://patch.msgid.link/20260311123110.1471930-1-edumazet@google.com Signed-off-by: Jakub Kicinski

net: add xmit recursion limit to tunnel xmit functions

2026-03-10T12:30:30+00:00

Tunnel xmit functions (iptunnel_xmit, ip6tunnel_xmit) lack their own recursion limit. When a bond device in broadcast mode has GRE tap interfaces as slaves, and those GRE tunnels route back through the bond, multicast/broadcast traffic triggers infinite recursion between bond_xmit_broadcast() and ip_tunnel_xmit()/ip6_tnl_xmit(), causing kernel stack overflow. The existing XMIT_RECURSION_LIMIT (8) in the no-qdisc path is not sufficient because tunnel recursion involves route lookups and full IP output, consuming much more stack per level. Use a lower limit of 4 (IP_TUNNEL_RECURSION_LIMIT) to prevent overflow. Add recursion detection using dev_xmit_recursion helpers directly in iptunnel_xmit() and ip6tunnel_xmit() to cover all IPv4/IPv6 tunnel paths including UDP encapsulated tunnels (VXLAN, Geneve, etc.). Move dev_xmit_recursion helpers from net/core/dev.h to public header include/linux/netdevice.h so they can be used by tunnel code. BUG: KASAN: stack-out-of-bounds in blake2s.constprop.0+0xe7/0x160 Write of size 32 at addr ffff88810033fed0 by task kworker/0:1/11 Workqueue: mld mld_ifc_work Call Trace: __build_flow_key.constprop.0 (net/ipv4/route.c:515) ip_rt_update_pmtu (net/ipv4/route.c:1073) iptunnel_xmit (net/ipv4/ip_tunnel_core.c:84) ip_tunnel_xmit (net/ipv4/ip_tunnel.c:847) gre_tap_xmit (net/ipv4/ip_gre.c:779) dev_hard_start_xmit (net/core/dev.c:3887) sch_direct_xmit (net/sched/sch_generic.c:347) __dev_queue_xmit (net/core/dev.c:4802) bond_dev_queue_xmit (drivers/net/bonding/bond_main.c:312) bond_xmit_broadcast (drivers/net/bonding/bond_main.c:5279) bond_start_xmit (drivers/net/bonding/bond_main.c:5530) dev_hard_start_xmit (net/core/dev.c:3887) __dev_queue_xmit (net/core/dev.c:4841) ip_finish_output2 (net/ipv4/ip_output.c:237) ip_output (net/ipv4/ip_output.c:438) iptunnel_xmit (net/ipv4/ip_tunnel_core.c:86) gre_tap_xmit (net/ipv4/ip_gre.c:779) dev_hard_start_xmit (net/core/dev.c:3887) sch_direct_xmit (net/sched/sch_generic.c:347) __dev_queue_xmit (net/core/dev.c:4802) bond_dev_queue_xmit (drivers/net/bonding/bond_main.c:312) bond_xmit_broadcast (drivers/net/bonding/bond_main.c:5279) bond_start_xmit (drivers/net/bonding/bond_main.c:5530) dev_hard_start_xmit (net/core/dev.c:3887) __dev_queue_xmit (net/core/dev.c:4841) ip_finish_output2 (net/ipv4/ip_output.c:237) ip_output (net/ipv4/ip_output.c:438) iptunnel_xmit (net/ipv4/ip_tunnel_core.c:86) ip_tunnel_xmit (net/ipv4/ip_tunnel.c:847) gre_tap_xmit (net/ipv4/ip_gre.c:779) dev_hard_start_xmit (net/core/dev.c:3887) sch_direct_xmit (net/sched/sch_generic.c:347) __dev_queue_xmit (net/core/dev.c:4802) bond_dev_queue_xmit (drivers/net/bonding/bond_main.c:312) bond_xmit_broadcast (drivers/net/bonding/bond_main.c:5279) bond_start_xmit (drivers/net/bonding/bond_main.c:5530) dev_hard_start_xmit (net/core/dev.c:3887) __dev_queue_xmit (net/core/dev.c:4841) mld_sendpack mld_ifc_work process_one_work worker_thread Fixes: 745e20f1b626 ("net: add a recursion limit in xmit path") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Link: https://patch.msgid.link/20260306160133.3852900-2-bestswngs@gmail.com Signed-off-by: Paolo Abeni

ipv4: ip_tunnel: spread netdev_lockdep_set_classes()

2026-01-09T02:02:35+00:00

Inspired by yet another syzbot report. IPv6 tunnels call netdev_lockdep_set_classes() for each tunnel type, while IPv4 currently centralizes netdev_lockdep_set_classes() call from ip_tunnel_init(). Make ip_tunnel_init() a macro, so that we have different lockdep classes per tunnel type. Fixes: 0bef512012b1 ("net: add netdev_lockdep_set_classes() to virtual drivers") Reported-by: syzbot+1240b33467289f5ab50b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/695d439f.050a0220.1c677c.0347.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260106172426.1760721-1-edumazet@google.com Signed-off-by: Jakub Kicinski