kernel/net/core, branch linux-rolling-lts

neighbour: restore protocol != 0 check in pneigh update

2026-03-19T15:08:21Z

[ Upstream commit cbada1048847a348797aec63a1d8056621cbe653 ] Prior to commit dc2a27e524ac ("neighbour: Update pneigh_entry in pneigh_create()."), a pneigh's protocol was updated only when the value of the NDA_PROTOCOL attribute was non-0. While moving the code, that check was removed. This is a small change of user-visible behavior, and inconsistent with the (non-proxy) neighbour behavior. Fixes: dc2a27e524ac ("neighbour: Update pneigh_entry in pneigh_create().") Signed-off-by: Sabrina Dubroca Reviewed-by: David Ahern Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/38c61de1bb032871a886aff9b9b52fe1cdd4cada.1772894876.git.sd@queasysnail.net Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

page_pool: store detach_time as ktime_t to avoid false-negatives

2026-03-19T15:08:20Z

[ Upstream commit 28b225282d44e2ef40e7f46cfdbd5d1b20b8874f ] While testing other changes in vng I noticed that nl_netdev.page_pool_check flakes. This never happens in real CI. Turns out vng may boot and get to that test in less than a second. page_pool_detached() records the detach time in seconds, so if vng is fast enough detach time is set to 0. Other code treats 0 as "not detached". detach_time is only used to report the state to the user, so it's not a huge deal in practice but let's fix it. Store the raw ktime_t (nanoseconds) instead. A nanosecond value of 0 is practically impossible. Acked-by: Jesper Dangaard Brouer Fixes: 69cb4952b6f6 ("net: page_pool: report when page pool was destroyed") Link: https://patch.msgid.link/20260310003907.3540019-1-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: add xmit recursion limit to tunnel xmit functions

2026-03-19T15:08:17Z

[ 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

xdp: produce a warning when calculated tailroom is negative

2026-03-12T11:10:02Z

[ Upstream commit 8821e857759be9db3cde337ad328b71fe5c8a55f ] Many ethernet drivers report xdp Rx queue frag size as being the same as DMA write size. However, the only user of this field, namely bpf_xdp_frags_increase_tail(), clearly expects a truesize. Such difference leads to unspecific memory corruption issues under certain circumstances, e.g. in ixgbevf maximum DMA write size is 3 KB, so when running xskxceiver's XDP_ADJUST_TAIL_GROW_MULTI_BUFF, 6K packet fully uses all DMA-writable space in 2 buffers. This would be fine, if only rxq->frag_size was properly set to 4K, but value of 3K results in a negative tailroom, because there is a non-zero page offset. We are supposed to return -EINVAL and be done with it in such case, but due to tailroom being stored as an unsigned int, it is reported to be somewhere near UINT_MAX, resulting in a tail being grown, even if the requested offset is too much (it is around 2K in the abovementioned test). This later leads to all kinds of unspecific calltraces. [ 7340.337579] xskxceiver[1440]: segfault at 1da718 ip 00007f4161aeac9d sp 00007f41615a6a00 error 6 [ 7340.338040] xskxceiver[1441]: segfault at 7f410000000b ip 00000000004042b5 sp 00007f415bffecf0 error 4 [ 7340.338179] in libc.so.6[61c9d,7f4161aaf000+160000] [ 7340.339230] in xskxceiver[42b5,400000+69000] [ 7340.340300] likely on CPU 6 (core 0, socket 6) [ 7340.340302] Code: ff ff 01 e9 f4 fe ff ff 0f 1f 44 00 00 4c 39 f0 74 73 31 c0 ba 01 00 00 00 f0 0f b1 17 0f 85 ba 00 00 00 49 8b 87 88 00 00 00 <4c> 89 70 08 eb cc 0f 1f 44 00 00 48 8d bd f0 fe ff ff 89 85 ec fe [ 7340.340888] likely on CPU 3 (core 0, socket 3) [ 7340.345088] Code: 00 00 00 ba 00 00 00 00 be 00 00 00 00 89 c7 e8 31 ca ff ff 89 45 ec 8b 45 ec 85 c0 78 07 b8 00 00 00 00 eb 46 e8 0b c8 ff ff <8b> 00 83 f8 69 74 24 e8 ff c7 ff ff 8b 00 83 f8 0b 74 18 e8 f3 c7 [ 7340.404334] Oops: general protection fault, probably for non-canonical address 0x6d255010bdffc: 0000 [#1] SMP NOPTI [ 7340.405972] CPU: 7 UID: 0 PID: 1439 Comm: xskxceiver Not tainted 6.19.0-rc1+ #21 PREEMPT(lazy) [ 7340.408006] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-5.fc42 04/01/2014 [ 7340.409716] RIP: 0010:lookup_swap_cgroup_id+0x44/0x80 [ 7340.410455] Code: 83 f8 1c 73 39 48 ba ff ff ff ff ff ff ff 03 48 8b 04 c5 20 55 fa bd 48 21 d1 48 89 ca 83 e1 01 48 d1 ea c1 e1 04 48 8d 04 90 <8b> 00 48 83 c4 10 d3 e8 c3 cc cc cc cc 31 c0 e9 98 b7 dd 00 48 89 [ 7340.412787] RSP: 0018:ffffcc5c04f7f6d0 EFLAGS: 00010202 [ 7340.413494] RAX: 0006d255010bdffc RBX: ffff891f477895a8 RCX: 0000000000000010 [ 7340.414431] RDX: 0001c17e3fffffff RSI: 00fa070000000000 RDI: 000382fc7fffffff [ 7340.415354] RBP: 00fa070000000000 R08: ffffcc5c04f7f8f8 R09: ffffcc5c04f7f7d0 [ 7340.416283] R10: ffff891f4c1a7000 R11: ffffcc5c04f7f9c8 R12: ffffcc5c04f7f7d0 [ 7340.417218] R13: 03ffffffffffffff R14: 00fa06fffffffe00 R15: ffff891f47789500 [ 7340.418229] FS: 0000000000000000(0000) GS:ffff891ffdfaa000(0000) knlGS:0000000000000000 [ 7340.419489] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 7340.420286] CR2: 00007f415bfffd58 CR3: 0000000103f03002 CR4: 0000000000772ef0 [ 7340.421237] PKRU: 55555554 [ 7340.421623] Call Trace: [ 7340.421987] [ 7340.422309] ? softleaf_from_pte+0x77/0xa0 [ 7340.422855] swap_pte_batch+0xa7/0x290 [ 7340.423363] zap_nonpresent_ptes.constprop.0.isra.0+0xd1/0x270 [ 7340.424102] zap_pte_range+0x281/0x580 [ 7340.424607] zap_pmd_range.isra.0+0xc9/0x240 [ 7340.425177] unmap_page_range+0x24d/0x420 [ 7340.425714] unmap_vmas+0xa1/0x180 [ 7340.426185] exit_mmap+0xe1/0x3b0 [ 7340.426644] __mmput+0x41/0x150 [ 7340.427098] exit_mm+0xb1/0x110 [ 7340.427539] do_exit+0x1b2/0x460 [ 7340.427992] do_group_exit+0x2d/0xc0 [ 7340.428477] get_signal+0x79d/0x7e0 [ 7340.428957] arch_do_signal_or_restart+0x34/0x100 [ 7340.429571] exit_to_user_mode_loop+0x8e/0x4c0 [ 7340.430159] do_syscall_64+0x188/0x6b0 [ 7340.430672] ? __do_sys_clone3+0xd9/0x120 [ 7340.431212] ? switch_fpu_return+0x4e/0xd0 [ 7340.431761] ? arch_exit_to_user_mode_prepare.isra.0+0xa1/0xc0 [ 7340.432498] ? do_syscall_64+0xbb/0x6b0 [ 7340.433015] ? __handle_mm_fault+0x445/0x690 [ 7340.433582] ? count_memcg_events+0xd6/0x210 [ 7340.434151] ? handle_mm_fault+0x212/0x340 [ 7340.434697] ? do_user_addr_fault+0x2b4/0x7b0 [ 7340.435271] ? clear_bhb_loop+0x30/0x80 [ 7340.435788] ? clear_bhb_loop+0x30/0x80 [ 7340.436299] ? clear_bhb_loop+0x30/0x80 [ 7340.436812] ? clear_bhb_loop+0x30/0x80 [ 7340.437323] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 7340.437973] RIP: 0033:0x7f4161b14169 [ 7340.438468] Code: Unable to access opcode bytes at 0x7f4161b1413f. [ 7340.439242] RSP: 002b:00007ffc6ebfa770 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca [ 7340.440173] RAX: fffffffffffffe00 RBX: 00000000000005a1 RCX: 00007f4161b14169 [ 7340.441061] RDX: 00000000000005a1 RSI: 0000000000000109 RDI: 00007f415bfff990 [ 7340.441943] RBP: 00007ffc6ebfa7a0 R08: 0000000000000000 R09: 00000000ffffffff [ 7340.442824] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 7340.443707] R13: 0000000000000000 R14: 00007f415bfff990 R15: 00007f415bfff6c0 [ 7340.444586] [ 7340.444922] Modules linked in: rfkill intel_rapl_msr intel_rapl_common intel_uncore_frequency_common skx_edac_common nfit libnvdimm kvm_intel vfat fat kvm snd_pcm irqbypass rapl iTCO_wdt snd_timer intel_pmc_bxt iTCO_vendor_support snd ixgbevf virtio_net soundcore i2c_i801 pcspkr libeth_xdp net_failover i2c_smbus lpc_ich failover libeth virtio_balloon joydev 9p fuse loop zram lz4hc_compress lz4_compress 9pnet_virtio 9pnet netfs ghash_clmulni_intel serio_raw qemu_fw_cfg [ 7340.449650] ---[ end trace 0000000000000000 ]--- The issue can be fixed in all in-tree drivers, but we cannot just trust OOT drivers to not do this. Therefore, make tailroom a signed int and produce a warning when it is negative to prevent such mistakes in the future. Fixes: bf25146a5595 ("bpf: add frags support to the bpf_xdp_adjust_tail() API") Reviewed-by: Aleksandr Loktionov Reviewed-by: Toke Høiland-Jørgensen Acked-by: Martin KaFai Lau Signed-off-by: Larysa Zaremba Link: https://patch.msgid.link/20260305111253.2317394-10-larysa.zaremba@intel.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

xdp: use modulo operation to calculate XDP frag tailroom

2026-03-12T11:10:01Z

[ Upstream commit 88b6b7f7b216108a09887b074395fa7b751880b1 ] The current formula for calculating XDP tailroom in mbuf packets works only if each frag has its own page (if rxq->frag_size is PAGE_SIZE), this defeats the purpose of the parameter overall and without any indication leads to negative calculated tailroom on at least half of frags, if shared pages are used. There are not many drivers that set rxq->frag_size. Among them: * i40e and enetc always split page uniformly between frags, use shared pages * ice uses page_pool frags via libeth, those are power-of-2 and uniformly distributed across page * idpf has variable frag_size with XDP on, so current API is not applicable * mlx5, mtk and mvneta use PAGE_SIZE or 0 as frag_size for page_pool As for AF_XDP ZC, only ice, i40e and idpf declare frag_size for it. Modulo operation yields good results for aligned chunks, they are all power-of-2, between 2K and PAGE_SIZE. Formula without modulo fails when chunk_size is 2K. Buffers in unaligned mode are not distributed uniformly, so modulo operation would not work. To accommodate unaligned buffers, we could define frag_size as data + tailroom, and hence do not subtract offset when calculating tailroom, but this would necessitate more changes in the drivers. Define rxq->frag_size as an even portion of a page that fully belongs to a single frag. When calculating tailroom, locate the data start within such portion by performing a modulo operation on page offset. Fixes: bf25146a5595 ("bpf: add frags support to the bpf_xdp_adjust_tail() API") Acked-by: Jakub Kicinski Reviewed-by: Aleksandr Loktionov Signed-off-by: Larysa Zaremba Link: https://patch.msgid.link/20260305111253.2317394-2-larysa.zaremba@intel.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: Provide a PREEMPT_RT specific check for netdev_queue::_xmit_lock

2026-03-12T11:09:59Z

[ Upstream commit b824c3e16c1904bf80df489e293d1e3cbf98896d ] After acquiring netdev_queue::_xmit_lock the number of the CPU owning the lock is recorded in netdev_queue::xmit_lock_owner. This works as long as the BH context is not preemptible. On PREEMPT_RT the softirq context is preemptible and without the softirq-lock it is possible to have multiple user in __dev_queue_xmit() submitting a skb on the same CPU. This is fine in general but this means also that the current CPU is recorded as netdev_queue::xmit_lock_owner. This in turn leads to the recursion alert and the skb is dropped. Instead checking the for CPU number, that owns the lock, PREEMPT_RT can check if the lockowner matches the current task. Add netif_tx_owned() which returns true if the current context owns the lock by comparing the provided CPU number with the recorded number. This resembles the current check by negating the condition (the current check returns true if the lock is not owned). On PREEMPT_RT use rt_mutex_owner() to return the lock owner and compare the current task against it. Use the new helper in __dev_queue_xmit() and netif_local_xmit_active() which provides a similar check. Update comments regarding pairing READ_ONCE(). Reported-by: Bert Karwatzki Closes: https://lore.kernel.org/all/20260216134333.412332-1-spasswolf@web.de Fixes: 3253cb49cbad4 ("softirq: Allow to drop the softirq-BKL lock on PREEMPT_RT") Signed-off-by: Sebastian Andrzej Siewior Reported-by: Bert Karwatzki Signed-off-by: Sebastian Andrzej Siewior Link: https://patch.msgid.link/20260302162631.uGUyIqDT@linutronix.de Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net: devmem: use READ_ONCE/WRITE_ONCE on binding->dev

2026-03-12T11:09:58Z

[ Upstream commit 40bf00ec2ee271df5ba67593991760adf8b5d0ed ] binding->dev is protected on the write-side in mp_dmabuf_devmem_uninstall() against concurrent writes, but due to the concurrent bare reads in net_devmem_get_binding() and validate_xmit_unreadable_skb() it should be wrapped in a READ_ONCE/WRITE_ONCE pair to make sure no compiler optimizations play with the underlying register in unforeseen ways. Doesn't present a critical bug because the known compiler optimizations don't result in bad behavior. There is no tearing on u64, and load omissions/invented loads would only break if additional binding->dev references were inlined together (they aren't right now). This just more strictly follows the linux memory model (i.e., "Lock-Protected Writes With Lockless Reads" in tools/memory-model/Documentation/access-marking.txt). Fixes: bd61848900bf ("net: devmem: Implement TX path") Signed-off-by: Bobby Eshleman Link: https://patch.msgid.link/20260302-devmem-membar-fix-v2-1-5b33c9cbc28b@meta.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

tcp: secure_seq: add back ports to TS offset

2026-03-12T11:09:58Z

[ Upstream commit 165573e41f2f66ef98940cf65f838b2cb575d9d1 ] This reverts 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets") tcp_tw_recycle went away in 2017. Zhouyan Deng reported off-path TCP source port leakage via SYN cookie side-channel that can be fixed in multiple ways. One of them is to bring back TCP ports in TS offset randomization. As a bonus, we perform a single siphash() computation to provide both an ISN and a TS offset. Fixes: 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets") Reported-by: Zhouyan Deng Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Acked-by: Florian Westphal Link: https://patch.msgid.link/20260302205527.1982836-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: annotate data-races around sk->sk_{data_ready,write_space}

2026-03-12T11:09:49Z

[ Upstream commit 2ef2b20cf4e04ac8a6ba68493f8780776ff84300 ] skmsg (and probably other layers) are changing these pointers while other cpus might read them concurrently. Add corresponding READ_ONCE()/WRITE_ONCE() annotations for UDP, TCP and AF_UNIX. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Reported-by: syzbot+87f770387a9e5dc6b79b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/699ee9fc.050a0220.1cd54b.0009.GAE@google.com/ Signed-off-by: Eric Dumazet Cc: Daniel Borkmann Cc: John Fastabend Cc: Jakub Sitnicki Cc: Willem de Bruijn Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260225131547.1085509-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: consume xmit errors of GSO frames

2026-03-04T12:20:52Z

[ Upstream commit 7aa767d0d3d04e50ae94e770db7db8197f666970 ] udpgro_frglist.sh and udpgro_bench.sh are the flakiest tests currently in NIPA. They fail in the same exact way, TCP GRO test stalls occasionally and the test gets killed after 10min. These tests use veth to simulate GRO. They attach a trivial ("return XDP_PASS;") XDP program to the veth to force TSO off and NAPI on. Digging into the failure mode we can see that the connection is completely stuck after a burst of drops. The sender's snd_nxt is at sequence number N [1], but the receiver claims to have received (rcv_nxt) up to N + 3 * MSS [2]. Last piece of the puzzle is that senders rtx queue is not empty (let's say the block in the rtx queue is at sequence number N - 4 * MSS [3]). In this state, sender sends a retransmission from the rtx queue with a single segment, and sequence numbers N-4*MSS:N-3*MSS [3]. Receiver sees it and responds with an ACK all the way up to N + 3 * MSS [2]. But sender will reject this ack as TCP_ACK_UNSENT_DATA because it has no recollection of ever sending data that far out [1]. And we are stuck. The root cause is the mess of the xmit return codes. veth returns an error when it can't xmit a frame. We end up with a loss event like this: ------------------------------------------------- | GSO super frame 1 | GSO super frame 2 | |-----------------------------------------------| | seg | seg | seg | seg | seg | seg | seg | seg | | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | ------------------------------------------------- x ok ok | ok ok ok \\ snd_nxt "x" means packet lost by veth, and "ok" means it went thru. Since veth has TSO disabled in this test it sees individual segments. Segment 1 is on the retransmit queue and will be resent. So why did the sender not advance snd_nxt even tho it clearly did send up to seg 8? tcp_write_xmit() interprets the return code from the core to mean that data has not been sent at all. Since TCP deals with GSO super frames, not individual segment the crux of the problem is that loss of a single segment can be interpreted as loss of all. TCP only sees the last return code for the last segment of the GSO frame (in <> brackets in the diagram above). Of course for the problem to occur we need a setup or a device without a Qdisc. Otherwise Qdisc layer disconnects the protocol layer from the device errors completely. We have multiple ways to fix this. 1) make veth not return an error when it lost a packet. While this is what I think we did in the past, the issue keeps reappearing and it's annoying to debug. The game of whack a mole is not great. 2) fix the damn return codes We only talk about NETDEV_TX_OK and NETDEV_TX_BUSY in the documentation, so maybe we should make the return code from ndo_start_xmit() a boolean. I like that the most, but perhaps some ancient, not-really-networking protocol would suffer. 3) make TCP ignore the errors It is not entirely clear to me what benefit TCP gets from interpreting the result of ip_queue_xmit()? Specifically once the connection is established and we're pushing data - packet loss is just packet loss? 4) this fix Ignore the rc in the Qdisc-less+GSO case, since it's unreliable. We already always return OK in the TCQ_F_CAN_BYPASS case. In the Qdisc-less case let's be a bit more conservative and only mask the GSO errors. This path is taken by non-IP-"networks" like CAN, MCTP etc, so we could regress some ancient thing. This is the simplest, but also maybe the hackiest fix? Similar fix has been proposed by Eric in the past but never committed because original reporter was working with an OOT driver and wasn't providing feedback (see Link). Link: https://lore.kernel.org/CANn89iJcLepEin7EtBETrZ36bjoD9LrR=k4cfwWh046GB+4f9A@mail.gmail.com Fixes: 1f59533f9ca5 ("qdisc: validate frames going through the direct_xmit path") Signed-off-by: Jakub Kicinski Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260223235100.108939-1-kuba@kernel.org Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin