From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f79.google.com (mail-oo1-f79.google.com [209.85.161.79]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 78B862EDD69 for ; Wed, 7 Jan 2026 11:03:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.79 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767783800; cv=none; b=PfdqAu+T/gXkJXOIlD1oUD2Ge/c2IWODmIUcSBnoYKMeOnN4JpHA2rcZkvo3tZXlShfXnBrk1aiSbsuWddKuTnCe5bqLVU+TiO3ET/NttfC1Rm39V8UioHVp4ePNASjNdbdisUniX8mPo7FAr67t3bGLXDzya7+GTUeaHdXm+Jo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767783800; c=relaxed/simple; bh=9YmFFHHYIqyVB3Ut9rjIEURsPfRSbWn9cithoGdSowA=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=kLYDSk2Dg2AJTeBF+tNDjhENo+ULI5G76MtjvrnGvIfuA9PX7WfjF/u58woYl6xnjFzCJ9T7YHRgv/xXHHg3tIfKAyDWeNOtvzSrvMkFjFyy7NvfME2MhXNRwWII21gD/yXA6+mpAPpK/EVdNdejN5fqh3PJGraRmJpvXTLCqws= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.79 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f79.google.com with SMTP id 006d021491bc7-65b2cd67cceso4264827eaf.0 for ; Wed, 07 Jan 2026 03:03:17 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767783796; x=1768388596; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=UAzea6RibarWVUjrp90ecxeeipp3LvJAd2KfQev/m34=; b=VY5d+5lRZwL2yckfu84UxkEnztB2RQP/rrUyKU+d1X8ZYF2i1QakT8A2QopL0VxxK5 OwDdWbHxBEyHqa7IqasHy12aMml7q059cPa9VgqKk/93SwFcUBwoFGMUcrMjfiZ/2O4L +hc/unNTEBQGytZUgBtC3b3OJoipiaUKx1O8E0+M1MdOnHO8CNeyqVwqVhQSPdiWh6oA GCtIiR1E8k0N9p1zV8QgwfXcPQI6zBDxFo67Wz89CdRiV87bCZ2oG1rmNOeS8oUr4zqt h4pCErUSLA4prjXpllVfANodFS7MuUiwMRnUjk7DuEL03l+LdqglMCJzE7ksQaQGqUlA X/8g== X-Forwarded-Encrypted: i=1; AJvYcCXVFRQ/8Q/o0lTGsmzNxwFSuS/b35KhgmqPUO7MdXyjdlGQREAOJHJGbQlQZWmfM37CNLiISLg=@vger.kernel.org X-Gm-Message-State: AOJu0YxgNDcHZ861Hf/nHV7wpNiSpcv8P7c8wm/eF6c5RPcbwvsC9Llw yUQG2/rgTWhnI8NHqQrFPk+RF6mhKGOqwKNl14BtwBlqDJJBHeONd2lrExkqQdAoozkPBi1Wb8T MP7m8Ux3dAsD46R2khdGsGBK92q0iB6OkMmbiS25//g4mO+un2pR+zn+C/cU= X-Google-Smtp-Source: AGHT+IE/bvj8Ni/UExwZ9hRKWGqxU4MJF5rRLxU1s8dA+C5hRjhru7rhpGVctzgUZNlHKEjaVoQwZh5ck52qF5n7Tui/gByk1X4H Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:7815:b0:659:9a49:9023 with SMTP id 006d021491bc7-65f5509c1admr623635eaf.80.1767783796217; Wed, 07 Jan 2026 03:03:16 -0800 (PST) Date: Wed, 07 Jan 2026 03:03:16 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <695e3d74.050a0220.1c677c.035f.GAE@google.com> Subject: [syzbot] [bridge?] KCSAN: data-race in br_fdb_update / br_fdb_update (8) From: syzbot To: bridge@lists.linux.dev, davem@davemloft.net, edumazet@google.com, horms@kernel.org, idosch@nvidia.com, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, razor@blackwall.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" 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: syzbot+bfab43087ad57222ce96@syzkaller.appspotmail.com 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 syzkaller@googlegroups.com. 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