netlink: 12 bytes leftover after parsing attributes in process `syz.7.2634'. ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.7.2634/13638 is trying to acquire lock: ffff88807a7c0eb8 (&nft_net->commit_mutex){+.+.}-{3:3}, at: nf_tables_dumpreset_obj+0x72/0xa0 net/netfilter/nf_tables_api.c:7996 but task is already holding lock: ffff888056d75690 (nlk_cb_mutex-NETFILTER){+.+.}-{3:3}, at: __netlink_dump_start+0xf4/0x7a0 net/netlink/af_netlink.c:2341 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (nlk_cb_mutex-NETFILTER){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x135/0xc80 kernel/locking/mutex.c:747 __netlink_dump_start+0xf4/0x7a0 net/netlink/af_netlink.c:2341 netlink_dump_start include/linux/netlink.h:338 [inline] ip_set_dump+0x15c/0x1f0 net/netfilter/ipset/ip_set_core.c:1717 nfnetlink_rcv_msg+0xcaf/0x1290 net/netfilter/nfnetlink.c:302 netlink_rcv_skb+0x235/0x4c0 net/netlink/af_netlink.c:2550 nfnetlink_rcv+0x2c9/0x2490 net/netfilter/nfnetlink.c:659 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x7b1/0x930 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8d0/0xbf0 net/netlink/af_netlink.c:1899 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x61b/0x980 net/socket.c:2595 ___sys_sendmsg+0x2a6/0x360 net/socket.c:2649 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2687 [inline] __se_sys_sendmsg+0x1d0/0x2c0 net/socket.c:2685 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (nfnl_subsys_ipset){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x135/0xc80 kernel/locking/mutex.c:747 ip_set_nfnl_get_byindex+0x67/0x230 net/netfilter/ipset/ip_set_core.c:909 set_match_v1_checkentry+0x71/0x230 net/netfilter/xt_set.c:139 xt_check_match+0x49d/0xc60 net/netfilter/x_tables.c:534 __nft_match_init+0x671/0x8b0 net/netfilter/nft_compat.c:522 nf_tables_newexpr net/netfilter/nf_tables_api.c:3307 [inline] nf_tables_newrule+0x176e/0x2870 net/netfilter/nf_tables_api.c:4140 nfnetlink_rcv_batch net/netfilter/nfnetlink.c:519 [inline] nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:639 [inline] nfnetlink_rcv+0x1133/0x2490 net/netfilter/nfnetlink.c:657 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x7b1/0x930 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8d0/0xbf0 net/netlink/af_netlink.c:1899 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x61b/0x980 net/socket.c:2595 ___sys_sendmsg+0x2a6/0x360 net/socket.c:2649 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2687 [inline] __se_sys_sendmsg+0x1d0/0x2c0 net/socket.c:2685 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&nft_net->commit_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x37ef/0x7d80 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x135/0xc80 kernel/locking/mutex.c:747 nf_tables_dumpreset_obj+0x72/0xa0 net/netfilter/nf_tables_api.c:7996 netlink_dump+0x738/0xec0 net/netlink/af_netlink.c:2269 __netlink_dump_start+0x57c/0x7a0 net/netlink/af_netlink.c:2377 netlink_dump_start include/linux/netlink.h:338 [inline] nft_netlink_dump_start_rcu+0xdb/0x1a0 net/netfilter/nf_tables_api.c:1124 nf_tables_getobj_reset+0x1e1/0x630 net/netfilter/nf_tables_api.c:8131 nfnetlink_rcv_msg+0x89c/0x1290 net/netfilter/nfnetlink.c:290 netlink_rcv_skb+0x235/0x4c0 net/netlink/af_netlink.c:2550 nfnetlink_rcv+0x2c9/0x2490 net/netfilter/nfnetlink.c:659 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x7b1/0x930 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8d0/0xbf0 net/netlink/af_netlink.c:1899 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x61b/0x980 net/socket.c:2595 ___sys_sendmsg+0x2a6/0x360 net/socket.c:2649 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2687 [inline] __se_sys_sendmsg+0x1d0/0x2c0 net/socket.c:2685 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 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.7.2634/13638: #0: ffff888056d75690 (nlk_cb_mutex-NETFILTER){+.+.}-{3:3}, at: __netlink_dump_start+0xf4/0x7a0 net/netlink/af_netlink.c:2341 stack backtrace: CPU: 0 PID: 13638 Comm: syz.7.2634 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 check_noncircular+0x2fc/0x400 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x37ef/0x7d80 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x135/0xc80 kernel/locking/mutex.c:747 nf_tables_dumpreset_obj+0x72/0xa0 net/netfilter/nf_tables_api.c:7996 netlink_dump+0x738/0xec0 net/netlink/af_netlink.c:2269 __netlink_dump_start+0x57c/0x7a0 net/netlink/af_netlink.c:2377 netlink_dump_start include/linux/netlink.h:338 [inline] nft_netlink_dump_start_rcu+0xdb/0x1a0 net/netfilter/nf_tables_api.c:1124 nf_tables_getobj_reset+0x1e1/0x630 net/netfilter/nf_tables_api.c:8131 nfnetlink_rcv_msg+0x89c/0x1290 net/netfilter/nfnetlink.c:290 netlink_rcv_skb+0x235/0x4c0 net/netlink/af_netlink.c:2550 nfnetlink_rcv+0x2c9/0x2490 net/netfilter/nfnetlink.c:659 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x7b1/0x930 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8d0/0xbf0 net/netlink/af_netlink.c:1899 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x61b/0x980 net/socket.c:2595 ___sys_sendmsg+0x2a6/0x360 net/socket.c:2649 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2687 [inline] __se_sys_sendmsg+0x1d0/0x2c0 net/socket.c:2685 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f767599ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f76768c7028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f7675c15fa0 RCX: 00007f767599ce59 RDX: 000000002404c08a RSI: 0000200000000340 RDI: 0000000000000003 RBP: 00007f7675a32e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7675c16038 R14: 00007f7675c15fa0 R15: 00007ffe9450aca8