kernel/linux.git/net/core/dev.h, branch v6.12.80

net: add xmit recursion limit to tunnel xmit functions

2026-03-25T10:08:28+00:00

[ Upstream commit 6f1a9140ecda3baba3d945b9a6155af4268aafc4 ] 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 Signed-off-by: Sasha Levin

net: page_pool: avoid false positive warning if NAPI was never added

2025-05-29T09:02:59+00:00

[ Upstream commit c1e00bc4be06cacee6307cedb9b55bbaddb5044d ] We expect NAPI to be in disabled state when page pool is torn down. But it is also legal if the NAPI is completely uninitialized. Reviewed-by: Mina Almasry Link: https://patch.msgid.link/20250206225638.1387810-4-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

netdev: prevent accessing NAPI instances from another namespace

2025-01-17T12:41:00+00:00

commit d1cacd74776895f6435941f86a1130e58f6dd226 upstream. The NAPI IDs were not fully exposed to user space prior to the netlink API, so they were never namespaced. The netlink API must ensure that at the very least NAPI instance belongs to the same netns as the owner of the genl sock. napi_by_id() can become static now, but it needs to move because of dev_get_by_napi_id(). Cc: stable@vger.kernel.org Fixes: 1287c1ae0fc2 ("netdev-genl: Support setting per-NAPI config values") Fixes: 27f91aaf49b3 ("netdev-genl: Add netlink framework functions for napi") Reviewed-by: Sridhar Samudrala Reviewed-by: Joe Damato Link: https://patch.msgid.link/20250106180137.1861472-1-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

net: softnet_data: Make xmit per task.

2024-06-24T23:41:23+00:00

Softirq is preemptible on PREEMPT_RT. Without a per-CPU lock in local_bh_disable() there is no guarantee that only one device is transmitting at a time. With preemption and multiple senders it is possible that the per-CPU `recursion' counter gets incremented by different threads and exceeds XMIT_RECURSION_LIMIT leading to a false positive recursion alert. The `more' member is subject to similar problems if set by one thread for one driver and wrongly used by another driver within another thread. Instead of adding a lock to protect the per-CPU variable it is simpler to make xmit per-task. Sending and receiving skbs happens always in thread context anyway. Having a lock to protected the per-CPU counter would block/ serialize two sending threads needlessly. It would also require a recursive lock to ensure that the owner can increment the counter further. Make the softnet_data.xmit a task_struct member on PREEMPT_RT. Add needed wrapper. Cc: Ben Segall Cc: Daniel Bristot de Oliveira Cc: Dietmar Eggemann Cc: Juri Lelli Cc: Mel Gorman Cc: Steven Rostedt Cc: Valentin Schneider Cc: Vincent Guittot Signed-off-by: Sebastian Andrzej Siewior Link: https://patch.msgid.link/20240620132727.660738-9-bigeasy@linutronix.de Signed-off-by: Jakub Kicinski

net: Move dev_set_hwtstamp_phylib to net/core/dev.h

2024-06-18T01:25:53+00:00

This declaration was added to the header to be called from ethtool. ethtool is separated from core for code organization but it is not really a separate entity, it controls very core things. As ethtool is an internal stuff it is not wise to have it in netdevice.h. Move the declaration to net/core/dev.h instead. Remove the EXPORT_SYMBOL_GPL call as ethtool can not be built as a module. Reviewed-by: Willem de Bruijn Signed-off-by: Kory Maincent Link: https://lore.kernel.org/r/20240612-feature_ptp_netnext-v15-2-b2a086257b63@bootlin.com Signed-off-by: Jakub Kicinski

net: move sysctl_skb_defer_max to net_hotdata

2024-05-01T01:46:52+00:00

sysctl_skb_defer_max is used in TCP fast path, move it to net_hodata. Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240429134025.1233626-3-edumazet@google.com Signed-off-by: Jakub Kicinski

net: move dev_xmit_recursion() helpers to net/core/dev.h

2024-04-01T10:28:31+00:00

Move dev_xmit_recursion() and friends to net/core/dev.h They are only used from net/core/dev.c and net/core/filter.c. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: move kick_defer_list_purge() to net/core/dev.h

2024-04-01T10:28:31+00:00

kick_defer_list_purge() is defined in net/core/dev.c and used from net/core/skubff.c Because we need softnet_data, include from net/core/dev.h Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: move netdev_tstamp_prequeue into net_hotdata

2024-03-08T05:12:41+00:00

netdev_tstamp_prequeue is used in rx path. Move it to net_hotdata for better cache locality. Signed-off-by: Eric Dumazet Acked-by: Soheil Hassas Yeganeh Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240306160031.874438-4-edumazet@google.com Signed-off-by: Jakub Kicinski

net: move netdev_budget and netdev_budget to net_hotdata

2024-03-08T05:12:41+00:00

netdev_budget and netdev_budget are used in rx path (net_rx_action()) Move them into net_hotdata for better cache locality. Signed-off-by: Eric Dumazet Acked-by: Soheil Hassas Yeganeh Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240306160031.874438-3-edumazet@google.com Signed-off-by: Jakub Kicinski