====================================================== WARNING: possible circular locking dependency detected 4.14.275-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.1/10255 is trying to acquire lock: (&xt[i].mutex){+.+.}, at: [] target_revfn+0x43/0x210 net/netfilter/x_tables.c:354 but task is already holding lock: (&table[i].mutex){+.+.}, at: [] nfnl_lock net/netfilter/nfnetlink.c:61 [inline] (&table[i].mutex){+.+.}, at: [] nfnetlink_rcv_msg+0x726/0xc00 net/netfilter/nfnetlink.c:209 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&table[i].mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 nf_tables_netdev_event+0x10d/0x4d0 net/netfilter/nf_tables_netdev.c:122 notifier_call_chain+0x108/0x1a0 kernel/notifier.c:93 call_netdevice_notifiers_info net/core/dev.c:1667 [inline] call_netdevice_notifiers net/core/dev.c:1683 [inline] rollback_registered_many+0x765/0xba0 net/core/dev.c:7211 rollback_registered+0xca/0x170 net/core/dev.c:7253 unregister_netdevice_queue+0x1b4/0x360 net/core/dev.c:8274 unregister_netdevice include/linux/netdevice.h:2444 [inline] __tun_detach+0xca2/0xf60 drivers/net/tun.c:584 tun_detach drivers/net/tun.c:594 [inline] tun_chr_close+0x41/0x60 drivers/net/tun.c:2732 __fput+0x25f/0x7a0 fs/file_table.c:210 task_work_run+0x11f/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #1 (rtnl_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 unregister_netdevice_notifier+0x5e/0x2b0 net/core/dev.c:1630 tee_tg_destroy+0x5c/0xb0 net/netfilter/xt_TEE.c:123 cleanup_entry+0x1fd/0x2d0 net/ipv4/netfilter/ip_tables.c:666 __do_replace+0x38d/0x570 net/ipv4/netfilter/ip_tables.c:1086 do_replace net/ipv4/netfilter/ip_tables.c:1142 [inline] do_ipt_set_ctl+0x256/0x3a0 net/ipv4/netfilter/ip_tables.c:1676 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x5f/0xb0 net/netfilter/nf_sockopt.c:115 ip_setsockopt net/ipv4/ip_sockglue.c:1255 [inline] ip_setsockopt+0x94/0xb0 net/ipv4/ip_sockglue.c:1240 tcp_setsockopt+0x7b/0xc0 net/ipv4/tcp.c:2830 SYSC_setsockopt net/socket.c:1865 [inline] SyS_setsockopt+0x110/0x1e0 net/socket.c:1844 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #0 (&xt[i].mutex){+.+.}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 target_revfn+0x43/0x210 net/netfilter/x_tables.c:354 xt_find_revision+0x15e/0x1d0 net/netfilter/x_tables.c:378 nfnl_compat_get+0x1f7/0x870 net/netfilter/nft_compat.c:678 nfnetlink_rcv_msg+0x9bb/0xc00 net/netfilter/nfnetlink.c:214 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2446 nfnetlink_rcv+0x1ab/0x1da0 net/netfilter/nfnetlink.c:515 netlink_unicast_kernel net/netlink/af_netlink.c:1294 [inline] netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1320 netlink_sendmsg+0x648/0xbc0 net/netlink/af_netlink.c:1891 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb5/0x100 net/socket.c:656 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062 __sys_sendmsg+0xa3/0x120 net/socket.c:2096 SYSC_sendmsg net/socket.c:2107 [inline] SyS_sendmsg+0x27/0x40 net/socket.c:2103 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb other info that might help us debug this: Chain exists of: &xt[i].mutex --> rtnl_mutex --> &table[i].mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&table[i].mutex); lock(rtnl_mutex); lock(&table[i].mutex); lock(&xt[i].mutex); *** DEADLOCK *** 1 lock held by syz-executor.1/10255: #0: (&table[i].mutex){+.+.}, at: [] nfnl_lock net/netfilter/nfnetlink.c:61 [inline] #0: (&table[i].mutex){+.+.}, at: [] nfnetlink_rcv_msg+0x726/0xc00 net/netfilter/nfnetlink.c:209 stack backtrace: CPU: 0 PID: 10255 Comm: syz-executor.1 Not tainted 4.14.275-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1905 [inline] check_prevs_add kernel/locking/lockdep.c:2022 [inline] validate_chain kernel/locking/lockdep.c:2464 [inline] __lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 target_revfn+0x43/0x210 net/netfilter/x_tables.c:354 xt_find_revision+0x15e/0x1d0 net/netfilter/x_tables.c:378 nfnl_compat_get+0x1f7/0x870 net/netfilter/nft_compat.c:678 nfnetlink_rcv_msg+0x9bb/0xc00 net/netfilter/nfnetlink.c:214 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2446 nfnetlink_rcv+0x1ab/0x1da0 net/netfilter/nfnetlink.c:515 netlink_unicast_kernel net/netlink/af_netlink.c:1294 [inline] netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1320 netlink_sendmsg+0x648/0xbc0 net/netlink/af_netlink.c:1891 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb5/0x100 net/socket.c:656 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062 __sys_sendmsg+0xa3/0x120 net/socket.c:2096 SYSC_sendmsg net/socket.c:2107 [inline] SyS_sendmsg+0x27/0x40 net/socket.c:2103 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7feddcad80e9 RSP: 002b:00007feddb44d168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007feddcbeaf60 RCX: 00007feddcad80e9 RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003 RBP: 00007feddcb3208d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffefeaac9df R14: 00007feddb44d300 R15: 0000000000022000 IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready uinput: abs_flat #00 out of range: 1024 (min:0/max:2) kvm: emulating exchange as write [U] ^@ [U] ^@ [U] ^@ [U] ^@^@ [U] ^@ [U] ^@ cramfs: bad compressed blocksize 4169137928 cramfs: bad compressed blocksize 4169137928 audit: type=1800 audit(1649859555.099:7): pid=10668 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed" comm="syz-executor.2" name="file0" dev="loop2" ino=125829364 res=0 netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'. unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'.