On Wed, Jan 7, 2026 at 12:03 PM syzbot <[email protected]> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: f0b9d8eb98df Merge tag 'nfsd-6.19-3' of git://git.kernel.o.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1304c922580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=b319ff1b6a2797ca > dashboard link: https://syzkaller.appspot.com/bug?extid=bfab43087ad57222ce96 > compiler: Debian clang version 20.1.8 > (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: > https://storage.googleapis.com/syzbot-assets/f91c35600c27/disk-f0b9d8eb.raw.xz > vmlinux: > https://storage.googleapis.com/syzbot-assets/9edb3553b7a5/vmlinux-f0b9d8eb.xz > kernel image: > https://storage.googleapis.com/syzbot-assets/4d762ee145b8/bzImage-f0b9d8eb.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: [email protected] > > bridge0: received packet on bridge_slave_0 with own address as source address > (addr:aa:aa:aa:aa:aa:1b, vlan:0) > bridge0: received packet on bridge_slave_0 with own address as source address > (addr:aa:aa:aa:aa:aa:1b, vlan:0) > ================================================================== > BUG: KCSAN: data-race in br_fdb_update / br_fdb_update > > read to 0xffff88811a0655c0 of 8 bytes by interrupt on cpu 1: > br_fdb_update+0x106/0x460 net/bridge/br_fdb.c:1005 > br_handle_frame_finish+0x340/0xfc0 net/bridge/br_input.c:144 > br_nf_hook_thresh+0x1eb/0x220 net/bridge/br_netfilter_hooks.c:-1 > br_nf_pre_routing_finish_ipv6+0x4d1/0x570 net/bridge/br_netfilter_ipv6.c:-1 > NF_HOOK include/linux/netfilter.h:318 [inline] > br_nf_pre_routing_ipv6+0x1fa/0x2b0 net/bridge/br_netfilter_ipv6.c:184 > br_nf_pre_routing+0x52b/0xbd0 net/bridge/br_netfilter_hooks.c:508 > nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] > nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] > br_handle_frame+0x4f0/0x9e0 net/bridge/br_input.c:442 > __netif_receive_skb_core+0x5df/0x1920 net/core/dev.c:6026 > __netif_receive_skb_one_core net/core/dev.c:6137 [inline] > __netif_receive_skb+0x59/0x270 net/core/dev.c:6252 > process_backlog+0x228/0x420 net/core/dev.c:6604 > __napi_poll+0x5f/0x300 net/core/dev.c:7668 > napi_poll net/core/dev.c:7731 [inline] > net_rx_action+0x425/0x8c0 net/core/dev.c:7883 > handle_softirqs+0xba/0x290 kernel/softirq.c:622 > do_softirq+0x45/0x60 kernel/softirq.c:523 > __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450 > local_bh_enable include/linux/bottom_half.h:33 [inline] > __alloc_skb+0x476/0x4b0 net/core/skbuff.c:674 > alloc_skb include/linux/skbuff.h:1383 [inline] > wg_socket_send_buffer_to_peer+0x35/0x120 drivers/net/wireguard/socket.c:192 > wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline] > wg_packet_handshake_send_worker+0x10d/0x160 drivers/net/wireguard/send.c:51 > process_one_work kernel/workqueue.c:3257 [inline] > process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340 > worker_thread+0x582/0x770 kernel/workqueue.c:3421 > kthread+0x489/0x510 kernel/kthread.c:463 > ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 > > write to 0xffff88811a0655c0 of 8 bytes by interrupt on cpu 0: > br_fdb_update+0x13e/0x460 net/bridge/br_fdb.c:1006 > br_handle_frame_finish+0x340/0xfc0 net/bridge/br_input.c:144 > br_nf_hook_thresh+0x1eb/0x220 net/bridge/br_netfilter_hooks.c:-1 > br_nf_pre_routing_finish_ipv6+0x4d1/0x570 net/bridge/br_netfilter_ipv6.c:-1 > NF_HOOK include/linux/netfilter.h:318 [inline] > br_nf_pre_routing_ipv6+0x1fa/0x2b0 net/bridge/br_netfilter_ipv6.c:184 > br_nf_pre_routing+0x52b/0xbd0 net/bridge/br_netfilter_hooks.c:508 > nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] > nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] > br_handle_frame+0x4f0/0x9e0 net/bridge/br_input.c:442 > __netif_receive_skb_core+0x5df/0x1920 net/core/dev.c:6026 > __netif_receive_skb_one_core net/core/dev.c:6137 [inline] > __netif_receive_skb+0x59/0x270 net/core/dev.c:6252 > process_backlog+0x228/0x420 net/core/dev.c:6604 > __napi_poll+0x5f/0x300 net/core/dev.c:7668 > napi_poll net/core/dev.c:7731 [inline] > net_rx_action+0x425/0x8c0 net/core/dev.c:7883 > handle_softirqs+0xba/0x290 kernel/softirq.c:622 > do_softirq+0x45/0x60 kernel/softirq.c:523 > __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450 > local_bh_enable include/linux/bottom_half.h:33 [inline] > fpregs_unlock arch/x86/include/asm/fpu/api.h:77 [inline] > kernel_fpu_end+0x6c/0x80 arch/x86/kernel/fpu/core.c:480 > blake2s_compress+0x67/0x1740 lib/crypto/x86/blake2s.h:42 > blake2s_update+0xa3/0x160 lib/crypto/blake2s.c:119 > hmac+0x141/0x270 drivers/net/wireguard/noise.c:324 > kdf+0x10b/0x1d0 drivers/net/wireguard/noise.c:375 > mix_dh drivers/net/wireguard/noise.c:413 [inline] > wg_noise_handshake_create_initiation+0x1ac/0x520 > drivers/net/wireguard/noise.c:550 > wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:34 [inline] > wg_packet_handshake_send_worker+0xb2/0x160 drivers/net/wireguard/send.c:51 > process_one_work kernel/workqueue.c:3257 [inline] > process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340 > worker_thread+0x582/0x770 kernel/workqueue.c:3421 > kthread+0x489/0x510 kernel/kthread.c:463 > ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 > > value changed: 0x0000000100026abc -> 0x0000000100026abd > > Reported by Kernel Concurrency Sanitizer on: > CPU: 0 UID: 0 PID: 8678 Comm: kworker/u8:42 Not tainted syzkaller #0 > PREEMPT(voluntary) > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 10/25/2025 > Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker > ================================================================== > net_ratelimit: 6540 callbacks suppressed > bridge0: received packet on bridge_slave_0 with own address as source address > (addr:aa:aa:aa:aa:aa:aa, vlan:0) > bridge0: received packet on veth0_to_bridge with own address as source > address (addr:aa:aa:aa:aa:aa:aa, vlan:0) > bridge0: received packet on bridge_slave_0 with own address as source address > (addr:aa:aa:aa:aa:aa:0c, vlan:0) > bridge0: received packet on veth0_to_bridge with own address as source > address (addr:aa:aa:aa:aa:aa:0c, vlan:0) > bridge0: received packet on veth0_to_bridge with own address as source > address (addr:96:6e:14:75:db:9d, vlan:0) > bridge0: received packet on veth0_to_bridge with own address as source > address (addr:96:6e:14:75:db:9d, vlan:0) > bridge0: received packet on bridge_slave_0 with own address as source address > (addr:aa:aa:aa:aa:aa:0c, vlan:0) > bridge0: received packet on veth0_to_bridge with own address as source > address (addr:aa:aa:aa:aa:aa:0c, vlan:0) > bridge0: received packet on bridge_slave_0 with own address as source address > (addr:aa:aa:aa:aa:aa:1b, vlan:0) > bridge0: received packet on bridge_slave_0 with own address as source address > (addr:aa:aa:aa:aa:aa:1b, vlan:0) > net_ratelimit: 7050 callbacks suppressed > bridge0: received packet on bridge_slave_0 with own address as source address > (addr:aa:aa:aa:aa:aa:aa, vlan:0) > bridge0: received packet on veth0_to_bridge with own address as source > address (addr:aa:aa:aa:aa:aa:aa, vlan:0) > bridge0: received packet on bridge_slave_0 with own address as source address > (addr:aa:aa:aa:aa:aa:0c, vlan:0) > bridge0: received packet on veth0_to_bridge with own address as source > address (addr:aa:aa:aa:aa:aa:0c, vlan:0) > bridge0: received packet on veth0_to_bridge with own address as source > address (addr:96:6e:14:75:db:9d, vlan:0) > bridge0: received packet on veth0_to_bridge with own address as source > address (addr:96:6e:14:75:db:9d, vlan:0) > bridge0: received packet on bridge_slave_0 with own address as source address > (addr:aa:aa:aa:aa:aa:0c, vlan:0) > bridge0: received packet on veth0_to_bridge with own address as source > address (addr:aa:aa:aa:aa:aa:0c, vlan:0) > bridge0: received packet on bridge_slave_0 with own address as source address > (addr:aa:aa:aa:aa:aa:1b, vlan:0) > bridge0: received packet on bridge_slave_0 with own address as source address > (addr:aa:aa:aa:aa:aa:1b, vlan:0) > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at [email protected]. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup
I am taking care of this issue, I will add the syzbot tags when sending V3 of https://lore.kernel.org/netdev/CANn89iLaMpL1Kz=t13b0egz+m5dbxupxx8opkd1v-vwbakz...@mail.gmail.com/T/#m19446ad4b132da817bda52a98a77a815034ed020 Thanks !
