From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.210.71 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793913452; b=Q/B95JcwjmV0J35q6obegjyT2Ez+rcTEOiyqhrcZx79Y3AxqrauApsvlnEcVSPLARZxM zWTSnNZYGYxRPTSmEkrhHCNB01H2F+oomkJNqLA+spHW34std1GXxbImq86bwdVcbxW1d eqvHyNqMhaIc9DUaE1/9Gw+05tN6Wi7p+ryG60xnccbniYn5ZdgoDp/64Sp6h2BtUNTCS HH6Grn7en8AzjM95LE7CTYrA20pRDEbVXSeRyMRChJdlZ+28dNc79ZrTDN3KE4hhDUt1I YGcMOW2spRyRQJiQwGCL4Mj0ZGene+u/2dihMk6S7faYrBER38waIw2enUz4eltbKCw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793913452; h=DMARC-Filter:Received:X-Google-DKIM-Signature:X-Forwarded-Encrypted: X-Gm-Message-State:MIME-Version:X-Received:Date: X-Google-Appengine-App-Id:X-Google-Appengine-App-Id-Alias:Message-ID: Subject:From:To:Content-Type; bh=kKvT1WZP63DDiif92MikpmY+JmPHkMKG8ncW+5LMjTE=; b=BQ836S51PoQ1LpESWzCXvlK+S+7HHqUsvsNVGiaGafnM7X7AXXIgEw6cBy/HXqBxIrim n1xrWaW/ofLOWoedVZlUS9Ozv+XCgwHLROnxMk86OP4crbnhFYoint3RmOlnfPffBXL8E 4zkpxBe4luNrL7k0CPyvPRukkLm6yVWkHA0igpp/3hOAD7yHJKmEIK7Xh92az/pycEdqm 2/HuM38phqaIbMuyIUO3LvXj2XZ6VQzukKEhzFvh9kC1PkjR2Xi0ozqucssfMNMw/Z5O+ dX7/a62VgppQX5zAtTm5j7o9qiAFfQDCoQRkHy7evILdLiiZ4DvSCPaxwcdngO+6RNw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=fail header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.remote-ip=209.85.210.71 Received: from mail-ot1-f71.google.com (mail-ot1-f71.google.com [209.85.210.71]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5201A606A32E for ; Thu, 5 Nov 2026 21:17:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 5201A606A32E 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-ot1-f71.google.com with SMTP id 46e09a7af769-8488f31d754so28185a34.0 for ; Thu, 05 Nov 2026 13:17:31 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793913451; x=1794518251; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=kKvT1WZP63DDiif92MikpmY+JmPHkMKG8ncW+5LMjTE=; b=q4wp+EHbd5sflfjjD4TWM4Jx/U3cR3g2ouVEWCCdcIm7Hl2bw3vfEwjHVZsDFEl+Bp RItbJcy1+XwtkLSmrfOirEE54NA3Ix7hMpOEyr0YHV9gmzrvCx020YNbjFJZh3m2v3/z POgG+Kb6xun6V1g8m3VcduAXpzZn7UUnJn0oqETxreqR/pozVUi6l5k+pIGjJmeeQ6vY cRLecnx0NCd2ABArs7VfQsHgeKr5eoDREESdsXFCy19U5jGihxt+ARPgITtsRrj6U6Fu /fg8Zn8yRR/lhAp6egC8VKLxJbZT/8N/vZLd5M4YivphA9cAzPzO/jWf7GGpeEZDYUPS QjtQ== X-Forwarded-Encrypted: i=1; AKwUvBz7yTQGp75Js61akhRCLuxjZhtG4CupK98U02/oh8aSNMgbSEl0RS8pyjkvARsM8/Tam4P2muMLokEMY2k=@vger.kernel.org X-Gm-Message-State: APuU4Z+iTXXHpxSkRW5e/iC2Ixu+W1rmghd7U/T5ljZS2xEjcd991WGr uMDU0cXIbJDoVnRcTJ9QrMc4Nzw3MTVKl21LQl61ka8ms49UYdwY6xc9znMeWoJedosLPF545ao lc5wMj5D9WV/2wWtYo+ePYo2i80YEOhTSsTyaKGol4rDZIxvkWzA1bunvPaE= X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 X-Received: by 2002:a05:6808:1985:b0:55c:8ee:a9c4 with SMTP id 5614622812f47-567e115e036mr383926b6e.43.1793913451254; Thu, 05 Nov 2026 13:17:31 -0800 (PST) Date: Thu, 05 Nov 2026 13:17:31 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6aecf26b.382bd2ce.33e041.0002.GAE@google.com> Subject: [syzbot] [netfilter?] WARNING in xt_dnat_target_v2 From: syzbot To: fw@strlen.de, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, pablo@netfilter.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 787268686c64 ipmr, ip6mr: queue netlink route queries out .. git tree: git://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git console output: https://syzkaller.appspot.com/x/log.txt?x=170b444e580000 kernel config: https://syzkaller.appspot.com/x/.config?x=d30e1495ee3ac817 dashboard link: https://syzkaller.appspot.com/bug?extid=2e819f6641708bb6ab9d compiler: Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=108b444e580000 AI-generated root cause summary: When an incoming TCP packet is rejected by an nftables reject rule (nft_reject_ipv4_eval), nf_send_reset() creates a TCP RST reply and attaches the original packet's conntrack entry via nf_ct_attach(), marking its ctinfo as IP_CT_RELATED_REPLY. As the RST packet traverses the NF_INET_LOCAL_OUT hook, nf_nat_ipv4_fn() passes it to nf_nat_inet_fn() because it is not an ICMP packet. In nf_nat_inet_fn(), IP_CT_RELATED_REPLY falls through to evaluation of uninitialized NAT mappings, executing rules in the LOCAL_OUT NAT chain. If the chain includes an xtables DNAT target (evaluated via nft_compat), xt_dnat_target_v2() triggers WARN_ON because its assertion checks only for IP_CT_NEW or IP_CT_RELATED, omitting IP_CT_RELATED_REPLY. full analysis: https://syzkaller.appspot.com/x/ai_root_cause?x=2e819f6641708bb6ab9d IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+2e819f6641708bb6ab9d@syzkaller.appspotmail.com ------------[ cut here ]------------ !(ct != NULL && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED)) WARNING: net/netfilter/xt_nat.c:154 at xt_dnat_target_v2+0x97/0xc0 net/netfilter/xt_nat.c:153, CPU#0: syz-executor145/6031 Modules linked in: CPU: 0 UID: 0 PID: 6031 Comm: syz-executor145 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026 RIP: 0010:xt_dnat_target_v2+0x97/0xc0 net/netfilter/xt_nat.c:153 Code: 74 22 41 83 e7 07 41 83 c7 fd bf fe ff ff ff 44 89 fe e8 ac 1e 90 f7 41 83 ff fe 72 25 e8 91 19 90 f7 eb 09 e8 8a 19 90 f7 90 <0f> 0b 90 4c 89 f7 48 89 de ba 01 00 00 00 5b 41 5e 41 5f e9 21 17 RSP: 0018:ffffc90000006de0 EFLAGS: 00010246 RAX: ffffffff8a38fc64 RBX: ffff8880614cd418 RCX: ffff88807c979f40 RDX: 0000000000000100 RSI: 0000000000000100 RDI: 00000000fffffffe RBP: ffffc90000006ed0 R08: 0000000000000100 R09: 0000000000000000 R10: ffffc900000070b0 R11: ffffffff8a38fbb0 R12: ffffffff919e5438 R13: 1ffff92000000dc4 R14: ffff8880247c8900 R15: 0000000000000001 FS: 0000555563505400(0000) GS:ffff88812361d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe16ab8280 CR3: 0000000034dea000 CR4: 00000000003526f0 Call Trace: nft_target_eval_xt+0x1ad/0x2b0 net/netfilter/nft_compat.c:100 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x48d/0x1b10 net/netfilter/nf_tables_core.c:285 nft_nat_do_chain+0x360/0x4b0 net/netfilter/nft_chain_nat.c:32 nf_nat_inet_fn+0x5de/0xb50 net/netfilter/nf_nat_core.c:931 nf_nat_ipv4_fn net/netfilter/nf_nat_proto.c:583 [inline] nf_nat_ipv4_local_fn+0x18c/0x570 net/netfilter/nf_nat_proto.c:738 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:633 nf_hook+0x22a/0x3a0 include/linux/netfilter.h:280 __ip_local_out+0x558/0x6a0 net/ipv4/ip_output.c:120 ip_local_out+0x2a/0x190 net/ipv4/ip_output.c:129 nf_send_reset+0xd8d/0x1530 net/ipv4/netfilter/nf_reject_ipv4.c:339 nft_reject_ipv4_eval+0xf6/0x230 net/ipv4/netfilter/nft_reject_ipv4.c:30 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x48d/0x1b10 net/netfilter/nf_tables_core.c:285 nft_do_chain_ipv4+0x195/0x290 net/netfilter/nft_chain_filter.c:24 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:633 nf_hook include/linux/netfilter.h:280 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:323 __netif_receive_skb_one_core net/core/dev.c:6433 [inline] __netif_receive_skb net/core/dev.c:6546 [inline] process_backlog+0xa6b/0x18b0 net/core/dev.c:6897 __napi_poll+0xaa/0x330 net/core/dev.c:7977 napi_poll net/core/dev.c:8040 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:8197 handle_softirqs+0x265/0x8d0 kernel/softirq.c:669 do_softirq+0x77/0xd0 kernel/softirq.c:569 __local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:923 [inline] __dev_queue_xmit+0x1efb/0x3920 net/core/dev.c:5121 neigh_output include/net/neighbour.h:554 [inline] ip_finish_output2+0xc4b/0x10b0 net/ipv4/ip_output.c:236 NF_HOOK_COND include/linux/netfilter.h:314 [inline] ip_output+0x29f/0x450 net/ipv4/ip_output.c:437 __ip_queue_xmit+0x10df/0x1b10 net/ipv4/ip_output.c:533 __tcp_transmit_skb+0x2d06/0x47b0 net/ipv4/tcp_output.c:1773 tcp_transmit_skb net/ipv4/tcp_output.c:1790 [inline] tcp_connect+0x1a7e/0x4990 net/ipv4/tcp_output.c:4451 tcp_v4_connect+0x1264/0x1b20 net/ipv4/tcp_ipv4.c:348 __inet_stream_connect+0x28c/0xf50 net/ipv4/af_inet.c:684 inet_stream_connect+0x66/0xa0 net/ipv4/af_inet.c:755 connect_socket net/socket.c:2143 [inline] __sys_connect_file net/socket.c:2168 [inline] __sys_connect+0x316/0x450 net/socket.c:2185 __do_sys_connect net/socket.c:2191 [inline] __se_sys_connect net/socket.c:2188 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:2188 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f81c24b2ff7 Code: 48 89 fa 4c 89 df e8 98 1d 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffe16aca280 EFLAGS: 00000202 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 0000555563505400 RCX: 00007f81c24b2ff7 RDX: 0000000000000010 RSI: 00007ffe16aca300 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000d2040002 R13: 00007f81c24eed50 R14: 00007ffe16aca300 R15: 00007f81c24ec06c --- 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 syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. 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