Hi Florian and Pablo, We hit the following warning from br_nf_local_in+0x157/0x180. [ 57.571874] WARNING: CPU: 1 PID: 0 at net/bridge/br_netfilter_hooks.c:616 br_nf_local_in+0x157/0x180 [br_netfilter] [ 57.572749] Modules linked in: xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat xt_addrtype xt_conntrack nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_isc si ib_umad rdma_cm ib_ipoib iw_cm ib_cm mlx5_ib ib_uverbs ib_core mlx5ctl mlx5_core [ 57.575158] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.8.0+ #19 [ 57.575700] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 57.576662] RIP: 0010:br_nf_local_in+0x157/0x180 [br_netfilter] [ 57.577195] Code: fe ff ff 41 bd 04 00 00 00 be 04 00 00 00 e9 4a ff ff ff be 04 00 00 00 48 89 ef e8 f3 a9 3c e1 66 83 ad b4 00 00 00 04 eb 91 <0f> 0b e9 f1 fe ff ff 0f 0b e9 df fe ff ff 48 89 df e8 b3 53 47 e1 [ 57.578722] RSP: 0018:ffff88885f845a08 EFLAGS: 00010202 [ 57.579207] RAX: 0000000000000002 RBX: ffff88812dfe8000 RCX: 0000000000000000 [ 57.579830] RDX: ffff88885f845a60 RSI: ffff8881022dc300 RDI: 0000000000000000 [ 57.580454] RBP: ffff88885f845a60 R08: 0000000000000001 R09: 0000000000000003 [ 57.581076] R10: 00000000ffff1300 R11: 0000000000000002 R12: 0000000000000000 [ 57.581695] R13: ffff8881047ffe00 R14: ffff888108dbee00 R15: ffff88814519b800 [ 57.582313] FS: 0000000000000000(0000) GS:ffff88885f840000(0000) knlGS:0000000000000000 [ 57.583040] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 57.583564] CR2: 000000c4206aa000 CR3: 0000000103847001 CR4: 0000000000370eb0 [ 57.584194] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 57.584820] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 57.585440] Call Trace: [ 57.585721] <IRQ> [ 57.585976] ? __warn+0x7d/0x130 [ 57.586323] ? br_nf_local_in+0x157/0x180 [br_netfilter] [ 57.586811] ? report_bug+0xf1/0x1c0 [ 57.587177] ? handle_bug+0x3f/0x70 [ 57.587539] ? exc_invalid_op+0x13/0x60 [ 57.587929] ? asm_exc_invalid_op+0x16/0x20 [ 57.588336] ? br_nf_local_in+0x157/0x180 [br_netfilter] [ 57.588825] nf_hook_slow+0x3d/0xd0 [ 57.589188] ? br_handle_vlan+0x4b/0x110 [ 57.589579] br_pass_frame_up+0xfc/0x150 [ 57.589970] ? br_port_flags_change+0x40/0x40 [ 57.590396] br_handle_frame_finish+0x346/0x5e0 [ 57.590837] ? ipt_do_table+0x32e/0x430 [ 57.591221] ? br_handle_local_finish+0x20/0x20 [ 57.591656] br_nf_hook_thresh+0x4b/0xf0 [br_netfilter] [ 57.592286] ? br_handle_local_finish+0x20/0x20 [ 57.592802] br_nf_pre_routing_finish+0x178/0x480 [br_netfilter] [ 57.593348] ? br_handle_local_finish+0x20/0x20 [ 57.593782] ? nf_nat_ipv4_pre_routing+0x25/0x60 [nf_nat] [ 57.594279] br_nf_pre_routing+0x24c/0x550 [br_netfilter] [ 57.594780] ? br_nf_hook_thresh+0xf0/0xf0 [br_netfilter] [ 57.595280] br_handle_frame+0x1f3/0x3d0 [ 57.595676] ? br_handle_local_finish+0x20/0x20 [ 57.596118] ? br_handle_frame_finish+0x5e0/0x5e0 [ 57.596566] __netif_receive_skb_core+0x25b/0xfc0 [ 57.597017] ? __napi_build_skb+0x37/0x40 [ 57.597418] __netif_receive_skb_list_core+0xfb/0x220 [ 57.597887] netif_receive_skb_list_internal+0x1c0/0x2d0 [ 57.598376] ? mlx5e_handle_rx_cqe_mpwrq+0x10f/0x1f0 [mlx5_core] [ 57.598969] napi_complete_done+0x101/0x180 [ 57.599383] mlx5e_napi_poll+0x1a2/0x6c0 [mlx5_core] [ 57.599894] __napi_poll+0x23/0x1b0 [ 57.600257] net_rx_action+0x256/0x2b0 [ 57.600641] __do_softirq+0xc1/0x297 [ 57.601014] irq_exit_rcu+0x6a/0x90 [ 57.601377] common_interrupt+0x5d/0xa0 [ 57.601765] </IRQ> [ 57.602028] <TASK> [ 57.602287] asm_common_interrupt+0x22/0x40 [ 57.602701] RIP: 0010:default_idle+0x13/0x20 [ 57.603125] Code: c0 08 00 00 00 4d 29 c8 4c 01 c7 4c 29 c2 e9 72 ff ff ff cc cc cc cc 8b 05 7a bf f0 00 85 c0 7e 07 0f 00 2d cf 50 2c 00 fb f4 <fa> c3 90 66 2e 0f 1f 84 00 00 00 00 00 65 48 8b 04 25 80 b5 02 00 [ 57.604718] RSP: 0018:ffff888101873ee0 EFLAGS: 00000242 [ 57.605202] RAX: 0000000000000001 RBX: 0000000000000001 RCX: 4000000000000000 [ 57.605826] RDX: 0000000000000000 RSI: 0000000000000083 RDI: 000000000002ea4c [ 57.606451] RBP: ffffffff82434ae0 R08: 0000000000000001 R09: 0000000000000000 [ 57.607079] R10: 0000000000000075 R11: 0000000000000000 R12: 0000000000000000 [ 57.607704] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 57.608337] default_idle_call+0x30/0xb0 [ 57.608730] do_idle+0x177/0x1e0 [ 57.609072] ? swake_up_locked.part.48+0x1a/0x40 [ 57.609517] cpu_startup_entry+0x26/0x30 [ 57.609909] start_secondary+0x107/0x130 [ 57.610302] secondary_startup_64_no_verify+0x15d/0x16b [ 57.610787] </TASK> It is from the commit: "netfilter: bridge: confirm multicast packets before passing them up the stack" https://lore.kernel.org/netdev/20240229000135.8780-3-pablo@xxxxxxxxxxxxx/ And the issue can be easliy reproduced on two B2B machines with the following configs. On hostA: BR=tst1 NIC1=enp8s0f0 NIC2=enp8s0f1 ip link add $BR type bridge iptables -A FORWARD -i $BR -j ACCEPT ip link set $NIC1 master $BR ip link set $NIC2 master $BR bridge vlan add dev $NIC1 vid 2 pvid untagged bridge vlan add dev $NIC2 vid 2 ip link set $BR type bridge vlan_filtering 1 ip link set $NIC1 up ip link set $NIC2 up ip link set $BR up On hostB: ns1=ns1 ns2=ns2 NIC1=enp8s0f0 NIC2=enp8s0f1 ip netns add $ns1 2>/dev/null ip netns add $ns2 2>/dev/null ip link set dev $NIC1 netns $ns1 ip -net ${ns1} addr add 1.1.1.1/24 dev $NIC1 ip -net ${ns1} link set dev $NIC1 up ip link set dev $NIC2 netns $ns2 ip -net ${ns2} link add link $NIC2 name $NIC2.2 type vlan id 2 ip -net ${ns2} addr add 1.1.1.2/24 dev $NIC2.2 ip -net ${ns2} link set dev $NIC2 up ip -net ${ns2} link set dev $NIC2.2 up Then run tcpdump on brigde interface (tst1) on hostA. The warning appears immediately after ping on hostB: ip netns exec ns1 ping 1.1.1.2 -c 1 Thanks! Jianbo
