audit: type=1400 audit(1587269330.634:8): avc: denied { execmem } for pid=6339 comm="syz-executor904" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1 ip_tables: iptables: counters copy to user failed while replacing table IPVS: ftp: loaded support on port[0] = 21 ip_tables: iptables: counters copy to user failed while replacing table ====================================================== WARNING: possible circular locking dependency detected 4.14.176-syzkaller #0 Not tainted ------------------------------------------------------ kworker/u4:2/25 is trying to acquire lock: (&table[i].mutex){+.+.}, at: [] nf_tables_netdev_event+0x10d/0x4d0 net/netfilter/nf_tables_netdev.c:122 but task is already holding lock: (rtnl_mutex){+.+.}, at: [] ip6gre_exit_net+0x70/0x580 net/ipv6/ip6_gre.c:1206 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (rtnl_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 unregister_netdevice_notifier+0x5e/0x2b0 net/core/dev.c:1634 tee_tg_destroy+0x5c/0xb0 net/netfilter/xt_TEE.c:123 cleanup_entry+0x169/0x220 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+0x255/0x39d net/ipv4/netfilter/ip_tables.c:1674 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 udp_setsockopt+0x45/0x80 net/ipv4/udp.c:2451 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+0x42/0xb7 -> #1 (&xt[i].mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 xt_find_revision+0x89/0x200 net/netfilter/x_tables.c:373 nfnl_compat_get+0x1f7/0x8a0 net/netfilter/nft_compat.c:678 nfnetlink_rcv_msg+0xa08/0xc00 net/netfilter/nfnetlink.c:214 netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2433 nfnetlink_rcv+0x1ab/0x1650 net/netfilter/nfnetlink.c:515 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline] netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1313 netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1878 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xc5/0x100 net/socket.c:656 ___sys_sendmsg+0x70a/0x840 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+0x42/0xb7 -> #0 (&table[i].mutex){+.+.}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 nf_tables_netdev_event+0x10d/0x4d0 net/netfilter/nf_tables_netdev.c:122 notifier_call_chain+0x107/0x1a0 kernel/notifier.c:93 call_netdevice_notifiers net/core/dev.c:1687 [inline] rollback_registered_many+0x694/0xa70 net/core/dev.c:7205 unregister_netdevice_many.part.0+0x16/0x1d0 net/core/dev.c:8278 unregister_netdevice_many+0x36/0x50 net/core/dev.c:8277 ip6gre_exit_net+0x3e3/0x580 net/ipv6/ip6_gre.c:1208 ops_exit_list.isra.0+0x9d/0x140 net/core/net_namespace.c:142 cleanup_net+0x3bb/0x820 net/core/net_namespace.c:484 process_one_work+0x813/0x1540 kernel/workqueue.c:2116 worker_thread+0x5d1/0x1070 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 other info that might help us debug this: Chain exists of: &table[i].mutex --> &xt[i].mutex --> rtnl_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rtnl_mutex); lock(&xt[i].mutex); lock(rtnl_mutex); lock(&table[i].mutex); *** DEADLOCK *** 4 locks held by kworker/u4:2/25: #0: ("%s""netns"){+.+.}, at: [] work_static include/linux/workqueue.h:199 [inline] #0: ("%s""netns"){+.+.}, at: [] set_work_data kernel/workqueue.c:619 [inline] #0: ("%s""netns"){+.+.}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ("%s""netns"){+.+.}, at: [] process_one_work+0x727/0x1540 kernel/workqueue.c:2087 #1: (net_cleanup_work){+.+.}, at: [] process_one_work+0x761/0x1540 kernel/workqueue.c:2091 #2: (net_mutex){+.+.}, at: [] cleanup_net+0x123/0x820 net/core/net_namespace.c:450 #3: (rtnl_mutex){+.+.}, at: [] ip6gre_exit_net+0x70/0x580 net/ipv6/ip6_gre.c:1206 stack backtrace: CPU: 0 PID: 25 Comm: kworker/u4:2 Not tainted 4.14.176-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x13e/0x194 lib/dump_stack.c:58 print_circular_bug.isra.0.cold+0x1c4/0x282 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+0x170/0x3f0 kernel/locking/lockdep.c:3994 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 nf_tables_netdev_event+0x10d/0x4d0 net/netfilter/nf_tables_netdev.c:122 notifier_call_chain+0x107/0x1a0 kernel/notifier.c:93 call_netdevice_notifiers net/core/dev.c:1687 [inline] rollback_registered_many+0x694/0xa70 net/core/dev.c:7205 unregister_netdevice_many.part.0+0x16/0x1d0 net/core/dev.c:8278 unregister_netdevice_many+0x36/0x50 net/core/dev.c:8277 ip6gre_exit_net+0x3e3/0x580 net/ipv6/ip6_gre.c:1208 ops_exit_list.isra.0+0x9d/0x140 net/core/net_namespace.c:142 cleanup_net+0x3bb/0x820 net/core/net_namespace.c:484 process_one_work+0x813/0x1540 kernel/workqueue.c:2116 worker_thread+0x5d1/0x1070 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table IPVS: ftp: loaded support on port[0] = 21 net_ratelimit: 6 callbacks suppressed ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table IPVS: ftp: loaded support on port[0] = 21 ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 net_ratelimit: 8 callbacks suppressed ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table