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 CFA04239E80 for ; Sat, 20 Dec 2025 00:58:29 +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=1766192311; cv=none; b=GdtB5QMW1Z3KM1VYBEznHznkkHKL5mYAPCdi4xQ+SraO1RhIR9shCaWF1KrPrwAAJ+46Mxb7WRokuWLDoEVovWriRt0pb23yn8+bSscVYqqo4jOW1ha65njP/XY+CtowT1I1EQY4QJcDNV8wBK6ZhKR7NkXNW6BmuXFcLHpRe7k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766192311; c=relaxed/simple; bh=76RkY53A53TE5vjruyOQ+9fxoxR/g3EA2S0do+GOSEM=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=VK2qRtQaeV95HVOx3fFOXXmF9bUQn71q2EqEFXD33qFJepvyQychsSaBgvflKoipL7AvQJAvq7/Ws/e08Wbvpf1G0REmrznDJ+r+qJGlzNlWkfH1agUYLywo5efZaDnaMg1LP9C69db/z61c4+BpeoW7aNHCbQpbepej06jWkRw= 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 006d021491bc7-656c35cd5b4so1499268eaf.0 for ; Fri, 19 Dec 2025 16:58:29 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1766192309; x=1766797109; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=WwApJ4ymW9qNlyX/ux7Ad8vgCZzQe62XlTOBLNe3WJU=; b=UvsPDWwrKmiNvRWUc3ntnTNLJKBGlx3KDSTXos+6VSHMdgS8TUKrW8SWVIRdI4dXto 8VVqMh0FyeVF0e7nCEULQbN9KpCSuQxyNTFG//3gpKnqEcslmyU+pu13UEdIQxt0gMWR K6NHPBychyGb6++lKfNsIjC2PVpssNQnDubYan8l+lFJ1/Cj7P4l7NmWtySFyVmeqY3K B01UYZohSzSXaPbNwcQwPcAmqC3/NkMAGlqyfu4zwzPCpAyVeWx+mOMD6iKhCzeByZzu aKVnt4nI+Ikc3HbUMAFYxFYJX7lAy92Y4mILxATTndfZ5pDFxBZRV9a7IGmAXTQU2ZbM 1XbA== X-Forwarded-Encrypted: i=1; AJvYcCUkeqmvr7UmSjsFyVO63twx5BhXHn3QyFqFtUmM71Lv6GGkn8mkqNeIbjoQTlom4Do7p/xA/18=@vger.kernel.org X-Gm-Message-State: AOJu0YzAiyUhyO7EfPEbEbJIoWF/XQVk1LevtNPhTOP330OAoF1nTyls po7otQO72PHfPn0IB2r0RRQHfzuVgv7OWisfhe5TWducKvw5TVzlhcRZ+t1lvzWFPr/BK5JYNqg LxYD4U+ENsREUUjqI+40RxERSDXpIA+fBfMsowgq6fmhJ7wqCdBjZoaG8DZ8= X-Google-Smtp-Source: AGHT+IH8z1xizs4/DgR2IxHVW2LrMd5szXgAdwV5XL5euymH4jWKMKV+aCIvYtTvLOOuayuVfcBFOkKm2lJ4xW/Uj4mdduejdkIc Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a4a:e602:0:b0:65d:bee:4c7 with SMTP id 006d021491bc7-65d0eb1f940mr1539827eaf.42.1766192308685; Fri, 19 Dec 2025 16:58:28 -0800 (PST) Date: Fri, 19 Dec 2025 16:58:28 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6945f4b4.a70a0220.207337.0121.GAE@google.com> Subject: [syzbot] [netfilter?] possible deadlock in nf_tables_dumpreset_obj 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: 8f0b4cce4481 Linux 6.19-rc1 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=104f2d92580000 kernel config: https://syzkaller.appspot.com/x/.config?x=a11e0f726bfb6765 dashboard link: https://syzkaller.appspot.com/bug?extid=ff16b505ec9152e5f448 compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 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-8f0b4cce.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/64c9a36f3f29/vmlinux-8f0b4cce.xz kernel image: https://storage.googleapis.com/syzbot-assets/27a5e8a8a4b8/bzImage-8f0b4cce.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ff16b505ec9152e5f448@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.3.970/9330 is trying to acquire lock: ffff888012d4ccd8 (&nft_net->commit_mutex){+.+.}-{4:4}, at: nf_tables_dumpreset_obj+0x6f/0xa0 net/netfilter/nf_tables_api.c:8491 but task is already holding lock: ffff88802bce36f0 (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_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #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:3527 [inline] nf_tables_newrule+0xedd/0x2910 net/netfilter/nf_tables_api.c:4358 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_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #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_obj+0x6f/0xa0 net/netfilter/nf_tables_api.c:8491 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:1286 nf_tables_getobj_reset+0x56b/0x6b0 net/netfilter/nf_tables_api.c:8626 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_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f 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.3.970/9330: #0: ffff88802bce36f0 (nlk_cb_mutex-NETFILTER){+.+.}-{4:4}, at: __netlink_dump_start+0x150/0x990 net/netlink/af_netlink.c:2404 stack backtrace: CPU: 0 UID: 0 PID: 9330 Comm: syz.3.970 Not tainted syzkaller #0 PREEMPT(full) 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_obj+0x6f/0xa0 net/netfilter/nf_tables_api.c:8491 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:1286 nf_tables_getobj_reset+0x56b/0x6b0 net/netfilter/nf_tables_api.c:8626 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_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb7e7b8f7c9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb7e8a9c038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fb7e7de5fa0 RCX: 00007fb7e7b8f7c9 RDX: 0000000004004004 RSI: 0000200000000140 RDI: 0000000000000003 RBP: 00007fb7e7c13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb7e7de6038 R14: 00007fb7e7de5fa0 R15: 00007fffe518fab8 --- 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