====================================================== WARNING: possible circular locking dependency detected 4.14.171-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.1/7304 is trying to acquire lock: (&table[i].mutex){+.+.}, at: [] nfnl_lock+0x24/0x30 net/netfilter/nfnetlink.c:61 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: -> #1 (&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 -> #0 (&table[i].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 nfnl_lock+0x24/0x30 net/netfilter/nfnetlink.c:61 ip_set_nfnl_put+0x120/0x320 net/netfilter/ipset/ip_set_core.c:730 set_match_v1_destroy+0x7c/0xb0 net/netfilter/xt_set.c:158 cleanup_match+0xc2/0x140 net/ipv6/netfilter/ip6_tables.c:491 cleanup_entry+0xbf/0x230 net/ipv4/netfilter/ip_tables.c:658 __do_replace+0x3c5/0x5b0 net/ipv4/netfilter/ip_tables.c:1086 do_replace net/ipv4/netfilter/ip_tables.c:1142 [inline] do_ipt_set_ctl+0x296/0x3ee net/ipv4/netfilter/ip_tables.c:1674 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115 ip_setsockopt net/ipv4/ip_sockglue.c:1255 [inline] ip_setsockopt+0x9b/0xb0 net/ipv4/ip_sockglue.c:1240 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: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&xt[i].mutex); lock(&table[i].mutex); lock(&xt[i].mutex); lock(&table[i].mutex); *** DEADLOCK *** 1 lock held by syz-executor.1/7304: #0: (&xt[i].mutex){+.+.}, at: [] xt_find_table_lock+0x3c/0x3d0 net/netfilter/x_tables.c:1092 stack backtrace: CPU: 1 PID: 7304 Comm: syz-executor.1 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 nfnl_lock+0x24/0x30 net/netfilter/nfnetlink.c:61 ip_set_nfnl_put+0x120/0x320 net/netfilter/ipset/ip_set_core.c:730 set_match_v1_destroy+0x7c/0xb0 net/netfilter/xt_set.c:158 cleanup_match+0xc2/0x140 net/ipv6/netfilter/ip6_tables.c:491 cleanup_entry+0xbf/0x230 net/ipv4/netfilter/ip_tables.c:658 __do_replace+0x3c5/0x5b0 net/ipv4/netfilter/ip_tables.c:1086 do_replace net/ipv4/netfilter/ip_tables.c:1142 [inline] do_ipt_set_ctl+0x296/0x3ee net/ipv4/netfilter/ip_tables.c:1674 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115 ip_setsockopt net/ipv4/ip_sockglue.c:1255 [inline] ip_setsockopt+0x9b/0xb0 net/ipv4/ip_sockglue.c:1240 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: 0033:0x45ef5a RSP: 002b:00007ffec0615eb8 EFLAGS: 00000206 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007ffec0615ee0 RCX: 000000000045ef5a RDX: 0000000000000040 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 000000000071fe80 R08: 00000000000002d8 R09: 0000000000004000 R10: 000000000071dd20 R11: 0000000000000206 R12: 0000000000000003 R13: 0000000000000000 R14: 0000000000000000 R15: 000000000071dcc0 ip_tables: iptables: counters copy to user failed while replacing table audit: type=1400 audit(1582441403.321:145): avc: denied { map } for pid=25598 comm="syz-executor.5" path="/proc/25598" dev="proc" ino=95531 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=dir permissive=1 audit: type=1400 audit(1582441403.321:146): avc: denied { execute } for pid=25598 comm="syz-executor.5" path="/proc/25598" dev="proc" ino=95531 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=dir permissive=1