====================================================== WARNING: possible circular locking dependency detected 4.14.171-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/7404 is trying to acquire lock: (rtnl_mutex){+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 but task is already holding lock: (&xt[i].mutex){+.+.}, at: [] xt_find_table_lock+0x3c/0x3d0 net/netfilter/x_tables.c:1092 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&xt[i].mutex){+.+.}: lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 xt_find_revision+0x82/0x200 net/netfilter/x_tables.c:373 nfnl_compat_get+0x229/0x950 net/netfilter/nft_compat.c:678 nfnetlink_rcv_msg+0xa08/0xc00 net/netfilter/nfnetlink.c:214 netlink_rcv_skb+0x14f/0x3c0 net/netlink/af_netlink.c:2432 nfnetlink_rcv+0x1ab/0x1650 net/netfilter/nfnetlink.c:515 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline] netlink_unicast+0x44d/0x650 net/netlink/af_netlink.c:1312 netlink_sendmsg+0x7c4/0xc60 net/netlink/af_netlink.c:1877 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xce/0x110 net/socket.c:656 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062 __sys_sendmsg+0xb9/0x140 net/socket.c:2096 SYSC_sendmsg net/socket.c:2107 [inline] SyS_sendmsg+0x2d/0x50 net/socket.c:2103 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #1 (&table[i].mutex){+.+.}: lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 nfnl_lock+0x24/0x30 net/netfilter/nfnetlink.c:61 nf_tables_netdev_event+0x13f/0x580 net/netfilter/nf_tables_netdev.c:122 notifier_call_chain+0x111/0x1b0 kernel/notifier.c:93 __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:401 call_netdevice_notifiers_info+0x56/0x70 net/core/dev.c:1671 call_netdevice_notifiers net/core/dev.c:1687 [inline] rollback_registered_many+0x70d/0xb60 net/core/dev.c:7205 rollback_registered+0xdd/0x180 net/core/dev.c:7247 unregister_netdevice_queue net/core/dev.c:8259 [inline] unregister_netdevice_queue+0x1ae/0x230 net/core/dev.c:8252 unregister_netdevice include/linux/netdevice.h:2442 [inline] ppp_release+0x18a/0x1b0 drivers/net/ppp/ppp_generic.c:408 __fput+0x275/0x7a0 fs/file_table.c:210 ____fput+0x16/0x20 fs/file_table.c:244 task_work_run+0x114/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1da/0x220 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+0x4bc/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #0 (rtnl_mutex){+.+.}: check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487 lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 unregister_netdevice_notifier+0x5f/0x2c0 net/core/dev.c:1634 tee_tg_destroy+0x61/0xc0 net/netfilter/xt_TEE.c:123 cleanup_entry+0x1a6/0x260 net/ipv6/netfilter/ip6_tables.c:684 __do_replace+0x3c5/0x5c0 net/ipv6/netfilter/ip6_tables.c:1105 do_replace net/ipv6/netfilter/ip6_tables.c:1161 [inline] do_ip6t_set_ctl+0x296/0x3f4 net/ipv6/netfilter/ip6_tables.c:1685 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115 ipv6_setsockopt net/ipv6/ipv6_sockglue.c:930 [inline] ipv6_setsockopt+0x105/0x130 net/ipv6/ipv6_sockglue.c:914 tcp_setsockopt net/ipv4/tcp.c:2826 [inline] tcp_setsockopt+0x84/0xd0 net/ipv4/tcp.c:2820 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:2968 SYSC_setsockopt net/socket.c:1865 [inline] SyS_setsockopt+0x13c/0x210 net/socket.c:1844 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 other info that might help us debug this: Chain exists of: rtnl_mutex --> &table[i].mutex --> &xt[i].mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&xt[i].mutex); lock(&table[i].mutex); lock(&xt[i].mutex); lock(rtnl_mutex); *** DEADLOCK *** 1 lock held by syz-executor.3/7404: #0: (&xt[i].mutex){+.+.}, at: [] xt_find_table_lock+0x3c/0x3d0 net/netfilter/x_tables.c:1092 stack backtrace: CPU: 1 PID: 7404 Comm: syz-executor.3 Not tainted 4.14.171-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+0x142/0x197 lib/dump_stack.c:58 print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487 lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 unregister_netdevice_notifier+0x5f/0x2c0 net/core/dev.c:1634 tee_tg_destroy+0x61/0xc0 net/netfilter/xt_TEE.c:123 cleanup_entry+0x1a6/0x260 net/ipv6/netfilter/ip6_tables.c:684 __do_replace+0x3c5/0x5c0 net/ipv6/netfilter/ip6_tables.c:1105 do_replace net/ipv6/netfilter/ip6_tables.c:1161 [inline] do_ip6t_set_ctl+0x296/0x3f4 net/ipv6/netfilter/ip6_tables.c:1685 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115 ipv6_setsockopt net/ipv6/ipv6_sockglue.c:930 [inline] ipv6_setsockopt+0x105/0x130 net/ipv6/ipv6_sockglue.c:914 tcp_setsockopt net/ipv4/tcp.c:2826 [inline] tcp_setsockopt+0x84/0xd0 net/ipv4/tcp.c:2820 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:2968 SYSC_setsockopt net/socket.c:1865 [inline] SyS_setsockopt+0x13c/0x210 net/socket.c:1844 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45ef7a RSP: 002b:00007ffc08c1d938 EFLAGS: 00000202 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007ffc08c1d960 RCX: 000000000045ef7a RDX: 0000000000000040 RSI: 0000000000000029 RDI: 0000000000000003 RBP: 000000000071dcc0 R08: 00000000000003b8 R09: 0000000000004000 R10: 000000000071bb60 R11: 0000000000000202 R12: 0000000000000003 R13: 0000000000000000 R14: 0000000000000029 R15: 000000000071bb00