From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f78.google.com (mail-oo1-f78.google.com [209.85.161.78]) (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 43092333448 for ; Mon, 5 Jan 2026 08:31:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767601887; cv=none; b=B5zhEjVkeYuc3wBsBEuvQ/fHdN1GUD4pSlweQUcVl+9RS3JRJx+ml08s79iqUQYUvwNGmF/QV0IDCkzEDzPgjTgEpb+JoGXXQExrPcPdO/cYfy3ki47tRCR7BG75vj9TyLulHmVm8gHBQquZc3e+OOXBbTSClSX718CwiTJxTSA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767601887; c=relaxed/simple; bh=HNmhhznQJuu33DLS+2t6q801usE+P2O3v/lqJE76mfo=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=q2BpBq62fANBBTEyvvxawtaSXtsZrVcP+Y4JLHf9P/XKWPlZMGjspHh8D+tGCpiaagkA0rg6mFtqyDMv9zlR2XCEddRRNM4dLVVFicQTPBqLWkufGEV7UT1GWsQjpX5084jRaTHu0Rc1s4GWuji5MdXfsyVZpWgRMsa3FhKoDVw= 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=209.85.161.78 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-f78.google.com with SMTP id 006d021491bc7-65b2cd67cceso27788911eaf.0 for ; Mon, 05 Jan 2026 00:31:25 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767601884; x=1768206684; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=9+E81ZK8kW7VMQC24dUJUhLhJ8nIdci8AoW4+w+wf2o=; b=wLpZOu62p5RWnWncuh4E/zn5eQDteTazTjVrX37xPnHPOTv/4Lj4sJyva9swxk+JRN 3Zz9kxUJRidmNJY0k0xaOXFtrfziE6rARG5k1YrJ1lYL9/nCS31BStorGVA3Q1lNTABB qLngDKjFM3dn/vLY8Les7dQpcSr4uLNcmvTXrv0WrCEOgE8hZ2euAtFZbjpBPm20Y95H Q3A32dSjUTHMr7L+rFZtgj9f6FXtdejFiPp6o/DO9YpKNjigWeGZIIAlkjiyQXH3pJbE je1jf+d3VeJbvzgKcJccPUmZVru7jLhSlwS9i/rv+P4kJId9IHUi8u2y6/DSaSaJc7+x djrw== X-Forwarded-Encrypted: i=1; AJvYcCVyBdFdXHAC9H06ZA21/iIAK63vJ4AROtJ/udFCyqq0oGOZDeMJbkeGCbMLdDJtnf44u6QY5rmYgdQMT09bkeo=@vger.kernel.org X-Gm-Message-State: AOJu0YxySFqLtJbnsY/S3gnUooagdlfy+sor+vaSYDTO2OmDrrDX65qB l/9W3itWEOuymhe3gaOMxkeUowuI53iaZ4qWnoJAOl0vSqJMOQiIaIancyokaOF9JGRPS2SWInh Lxc3KtZKDqMQvq+wR4X6cldbGeQfCupBM3ZkhKFXYCZfky+66523kc/QxWe8= X-Google-Smtp-Source: AGHT+IEdh0N1IsuCsTnZ+LDmkPk3wrN1GE3rg7IbJKz0xbqKlhXEd2WjJB7m1DqbuJTt3U2VLT2UILkrQkas9cqJGZC+cLxEcyF+ Precedence: bulk X-Mailing-List: netfilter-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:162a:b0:656:8548:d866 with SMTP id 006d021491bc7-65d0e9324e2mr20576414eaf.1.1767601884251; Mon, 05 Jan 2026 00:31:24 -0800 (PST) Date: Mon, 05 Jan 2026 00:31:24 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <695b76dc.050a0220.1c9965.0029.GAE@google.com> Subject: [syzbot] [netfilter?] possible deadlock in nf_tables_dumpreset_rules From: syzbot To: coreteam@netfilter.org, davem@davemloft.net, edumazet@google.com, fw@strlen.de, horms@kernel.org, kadlec@netfilter.org, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, pabeni@redhat.com, pablo@netfilter.org, phil@nwl.cc, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 54e82e93ca93 Merge tag 'core_urgent_for_v6.19_rc4' of git:.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=10b1ee22580000 kernel config: https://syzkaller.appspot.com/x/.config?x=8bfa57a8c0ab3aa8 dashboard link: https://syzkaller.appspot.com/bug?extid=ee287f5effa60050d9ac compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-54e82e93.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/c7af41d4f0f4/vmlinux-54e82e93.xz kernel image: https://storage.googleapis.com/syzbot-assets/02aa2250dd4f/bzImage-54e82e93.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ee287f5effa60050d9ac@syzkaller.appspotmail.com netlink: 48 bytes leftover after parsing attributes in process `syz.8.6539'. ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.8.6539/2008 is trying to acquire lock: ffff888052e32cd8 (&nft_net->commit_mutex){+.+.}-{4:4}, at: nf_tables_dumpreset_rules+0x6f/0xa0 net/netfilter/nf_tables_api.c:3913 but task is already holding lock: ffff888025cb16f0 (nlk_cb_mutex-NETFILTER){+.+.}-{4:4}, at: __netlink_dump_start+0x150/0x990 net/netlink/af_netlink.c:2404 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (nlk_cb_mutex-NETFILTER){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776 __netlink_dump_start+0x150/0x990 net/netlink/af_netlink.c:2404 netlink_dump_start include/linux/netlink.h:341 [inline] ip_set_dump+0x17f/0x210 net/netfilter/ipset/ip_set_core.c:1717 nfnetlink_rcv_msg+0x9fc/0x1200 net/netfilter/nfnetlink.c:302 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550 nfnetlink_rcv+0x1b3/0x430 net/netfilter/nfnetlink.c:669 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646 __sys_sendmsg+0x16d/0x220 net/socket.c:2678 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe8/0x680 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #1 (nfnl_subsys_ipset){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776 ip_set_nfnl_get_byindex+0x7c/0x290 net/netfilter/ipset/ip_set_core.c:909 set_target_v1_checkentry+0x1ac/0x570 net/netfilter/xt_set.c:313 xt_check_target+0x27c/0xa40 net/netfilter/x_tables.c:1038 nft_target_init+0x459/0x7d0 net/netfilter/nft_compat.c:267 nf_tables_newexpr net/netfilter/nf_tables_api.c:3550 [inline] nf_tables_newrule+0xedd/0x2910 net/netfilter/nf_tables_api.c:4419 nfnetlink_rcv_batch+0x190d/0x2350 net/netfilter/nfnetlink.c:526 nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:649 [inline] nfnetlink_rcv+0x3c1/0x430 net/netfilter/nfnetlink.c:667 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646 __sys_sendmsg+0x16d/0x220 net/socket.c:2678 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe8/0x680 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #0 (&nft_net->commit_mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1669/0x2890 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776 nf_tables_dumpreset_rules+0x6f/0xa0 net/netfilter/nf_tables_api.c:3913 netlink_dump+0x539/0xd30 net/netlink/af_netlink.c:2325 __netlink_dump_start+0x6d6/0x990 net/netlink/af_netlink.c:2440 netlink_dump_start include/linux/netlink.h:341 [inline] nft_netlink_dump_start_rcu+0x81/0x1f0 net/netfilter/nf_tables_api.c:1309 nf_tables_getrule_reset+0x56b/0x6b0 net/netfilter/nf_tables_api.c:4053 nfnetlink_rcv_msg+0x583/0x1200 net/netfilter/nfnetlink.c:290 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550 nfnetlink_rcv+0x1b3/0x430 net/netfilter/nfnetlink.c:669 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646 __sys_sendmsg+0x16d/0x220 net/socket.c:2678 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe8/0x680 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e other info that might help us debug this: Chain exists of: &nft_net->commit_mutex --> nfnl_subsys_ipset --> nlk_cb_mutex-NETFILTER Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(nlk_cb_mutex-NETFILTER); lock(nfnl_subsys_ipset); lock(nlk_cb_mutex-NETFILTER); lock(&nft_net->commit_mutex); *** DEADLOCK *** 1 lock held by syz.8.6539/2008: #0: ffff888025cb16f0 (nlk_cb_mutex-NETFILTER){+.+.}-{4:4}, at: __netlink_dump_start+0x150/0x990 net/netlink/af_netlink.c:2404 stack backtrace: CPU: 2 UID: 0 PID: 2008 Comm: syz.8.6539 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x275/0x340 kernel/locking/lockdep.c:2043 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1669/0x2890 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776 nf_tables_dumpreset_rules+0x6f/0xa0 net/netfilter/nf_tables_api.c:3913 netlink_dump+0x539/0xd30 net/netlink/af_netlink.c:2325 __netlink_dump_start+0x6d6/0x990 net/netlink/af_netlink.c:2440 netlink_dump_start include/linux/netlink.h:341 [inline] nft_netlink_dump_start_rcu+0x81/0x1f0 net/netfilter/nf_tables_api.c:1309 nf_tables_getrule_reset+0x56b/0x6b0 net/netfilter/nf_tables_api.c:4053 nfnetlink_rcv_msg+0x583/0x1200 net/netfilter/nfnetlink.c:290 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550 nfnetlink_rcv+0x1b3/0x430 net/netfilter/nfnetlink.c:669 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646 __sys_sendmsg+0x16d/0x220 net/socket.c:2678 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe8/0x680 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf702d579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f4f9f55c EFLAGS: 00000296 ORIG_RAX: 0000000000000172 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000080000240 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi --- 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