====================================================== WARNING: possible circular locking dependency detected 4.15.0+ #221 Not tainted ------------------------------------------------------ syzkaller467219/3974 is trying to acquire lock: (rtnl_mutex){+.+.}, at: [<00000000494b4ebe>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 but task is already holding lock: (&xt[i].mutex){+.+.}, at: [<000000008a074e5a>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1041 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&xt[i].mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1041 xt_request_find_table_lock+0x28/0xc0 net/netfilter/x_tables.c:1088 get_info+0x154/0x690 net/ipv6/netfilter/ip6_tables.c:989 do_ipt_get_ctl+0x159/0xac0 net/ipv4/netfilter/ip_tables.c:1699 nf_sockopt net/netfilter/nf_sockopt.c:104 [inline] nf_getsockopt+0x6a/0xc0 net/netfilter/nf_sockopt.c:122 ip_getsockopt+0x15c/0x220 net/ipv4/ip_sockglue.c:1571 tcp_getsockopt+0x82/0xd0 net/ipv4/tcp.c:3359 sock_common_getsockopt+0x95/0xd0 net/core/sock.c:2934 SYSC_getsockopt net/socket.c:1880 [inline] SyS_getsockopt+0x178/0x340 net/socket.c:1862 entry_SYSCALL_64_fastpath+0x29/0xa0 -> #1 (sk_lock-AF_INET){+.+.}: lock_sock_nested+0xc2/0x110 net/core/sock.c:2777 lock_sock include/net/sock.h:1463 [inline] do_ip_getsockopt+0x1b3/0x2170 net/ipv4/ip_sockglue.c:1329 ip_getsockopt+0x90/0x220 net/ipv4/ip_sockglue.c:1560 tcp_getsockopt+0x82/0xd0 net/ipv4/tcp.c:3359 sock_common_getsockopt+0x95/0xd0 net/core/sock.c:2934 SYSC_getsockopt net/socket.c:1880 [inline] SyS_getsockopt+0x178/0x340 net/socket.c:1862 entry_SYSCALL_64_fastpath+0x29/0xa0 -> #0 (rtnl_mutex){+.+.}: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 unregister_netdevice_notifier+0x91/0x4e0 net/core/dev.c:1673 clusterip_config_entry_put net/ipv4/netfilter/ipt_CLUSTERIP.c:114 [inline] clusterip_tg_destroy+0x389/0x6e0 net/ipv4/netfilter/ipt_CLUSTERIP.c:518 cleanup_entry+0x218/0x350 net/ipv4/netfilter/ip_tables.c:654 __do_replace+0x79d/0xa50 net/ipv4/netfilter/ip_tables.c:1089 do_replace net/ipv4/netfilter/ip_tables.c:1145 [inline] do_ipt_set_ctl+0x40f/0x5f0 net/ipv4/netfilter/ip_tables.c:1675 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115 ip_setsockopt+0x97/0xa0 net/ipv4/ip_sockglue.c:1259 tcp_setsockopt+0x82/0xd0 net/ipv4/tcp.c:2905 sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2975 SYSC_setsockopt net/socket.c:1849 [inline] SyS_setsockopt+0x189/0x360 net/socket.c:1828 entry_SYSCALL_64_fastpath+0x29/0xa0 other info that might help us debug this: Chain exists of: rtnl_mutex --> sk_lock-AF_INET --> &xt[i].mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&xt[i].mutex); lock(sk_lock-AF_INET); lock(&xt[i].mutex); lock(rtnl_mutex); *** DEADLOCK *** 1 lock held by syzkaller467219/3974: #0: (&xt[i].mutex){+.+.}, at: [<000000008a074e5a>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1041 stack backtrace: CPU: 1 PID: 3974 Comm: syzkaller467219 Not tainted 4.15.0+ #221 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+0x194/0x257 lib/dump_stack.c:53 print_circular_bug.isra.38+0x2cd/0x2dc kernel/locking/lockdep.c:1223 check_prev_add kernel/locking/lockdep.c:1863 [inline] check_prevs_add kernel/locking/lockdep.c:1976 [inline] validate_chain kernel/locking/lockdep.c:2417 [inline] __lock_acquire+0x30a8/0x3e00 kernel/locking/lockdep.c:3431 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 unregister_netdevice_notifier+0x91/0x4e0 net/core/dev.c:1673 clusterip_config_entry_put net/ipv4/netfilter/ipt_CLUSTERIP.c:114 [inline] clusterip_tg_destroy+0x389/0x6e0 net/ipv4/netfilter/ipt_CLUSTERIP.c:518 cleanup_entry+0x218/0x350 net/ipv4/netfilter/ip_tables.c:654 __do_replace+0x79d/0xa50 net/ipv4/netfilter/ip_tables.c:1089 do_replace net/ipv4/netfilter/ip_tables.c:1145 [inline] do_ipt_set_ctl+0x40f/0x5f0 net/ipv4/netfilter/ip_tables.c:1675 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115 ip_setsockopt+0x97/0xa0 net/ipv4/ip_sockglue.c:1259 tcp_setsockopt+0x82/0xd0 net/ipv4/tcp.c:2905 sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2975 SYSC_setsockopt net/socket.c:1849 [inline] SyS_setsockopt+0x189/0x360 net/socket.c:1828 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x444e1a RSP: 002b:00007fffd92ea138 EFLAGS: 00000206 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00000000006ce100 RCX: 0000000000444e1a RDX: 0000000000000040 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00000000006ce100 R08: 00000000000002d8 R09: 0000000000000001 R10: 00000000006ce528 R11: 0000000000000206 R12: 00007fffd92ea150 R13: 0000000000000003 R14: 00000000006d10a8 R15: 0000000000000000