audit: type=1400 audit(1518355929.971:7): avc: denied { map } for pid=4129 comm="syzkaller155740" path="/root/syzkaller155740699" dev="sda1" ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 ====================================================== WARNING: possible circular locking dependency detected 4.15.0+ #308 Not tainted ------------------------------------------------------ syzkaller155740/4129 is trying to acquire lock: (rtnl_mutex){+.+.}, at: [<00000000305eda53>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 but task is already holding lock: (&xt[i].mutex){+.+.}, at: [<000000008029e7d1>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1046 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:1046 xt_request_find_table_lock+0x28/0xc0 net/netfilter/x_tables.c:1093 get_info+0x154/0x690 net/ipv6/netfilter/ip6_tables.c:989 do_ip6t_get_ctl+0x159/0xaf0 net/ipv6/netfilter/ip6_tables.c:1710 nf_sockopt net/netfilter/nf_sockopt.c:104 [inline] nf_getsockopt+0x6a/0xc0 net/netfilter/nf_sockopt.c:122 ipv6_getsockopt+0x1df/0x2e0 net/ipv6/ipv6_sockglue.c:1371 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 do_syscall_64+0x282/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x26/0x9b -> #1 (sk_lock-AF_INET6){+.+.}: lock_sock_nested+0xc2/0x110 net/core/sock.c:2777 lock_sock include/net/sock.h:1463 [inline] do_ipv6_setsockopt.isra.8+0x3c5/0x39d0 net/ipv6/ipv6_sockglue.c:167 ipv6_setsockopt+0xd7/0x130 net/ipv6/ipv6_sockglue.c:922 sctp_setsockopt+0x2b6/0x61d0 net/sctp/socket.c:4104 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 do_syscall_64+0x282/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x26/0x9b -> #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 tee_tg_destroy+0x61/0xc0 net/netfilter/xt_TEE.c:123 cleanup_entry+0x242/0x380 net/ipv6/netfilter/ip6_tables.c:673 __do_replace+0x7ac/0xa70 net/ipv6/netfilter/ip6_tables.c:1108 do_replace net/ipv6/netfilter/ip6_tables.c:1164 [inline] do_ip6t_set_ctl+0x40f/0x5f0 net/ipv6/netfilter/ip6_tables.c:1686 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115 ipv6_setsockopt+0x10b/0x130 net/ipv6/ipv6_sockglue.c:927 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 do_syscall_64+0x282/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x26/0x9b other info that might help us debug this: Chain exists of: rtnl_mutex --> sk_lock-AF_INET6 --> &xt[i].mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&xt[i].mutex); lock(sk_lock-AF_INET6); lock(&xt[i].mutex); lock(rtnl_mutex); *** DEADLOCK *** 1 lock held by syzkaller155740/4129: #0: (&xt[i].mutex){+.+.}, at: [<000000008029e7d1>] xt_find_table_lock+0x3e/0x3e0 net/netfilter/x_tables.c:1046 stack backtrace: CPU: 0 PID: 4129 Comm: syzkaller155740 Not tainted 4.15.0+ #308 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 tee_tg_destroy+0x61/0xc0 net/netfilter/xt_TEE.c:123 cleanup_entry+0x242/0x380 net/ipv6/netfilter/ip6_tables.c:673 __do_replace+0x7ac/0xa70 net/ipv6/netfilter/ip6_tables.c:1108 do_replace net/ipv6/netfilter/ip6_tables.c:1164 [inline] do_ip6t_set_ctl+0x40f/0x5f0 net/ipv6/netfilter/ip6_tables.c:1686 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115 ipv6_setsockopt+0x10b/0x130 net/ipv6/ipv6_sockglue.c:927 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 do_syscall_64+0x282/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x26/0x9b RIP: 0033:0x445cba RSP: 002b:00007ffe832c5508 EFLAGS: 00000206 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00000000006ce800 RCX: 0000000000445cba RDX: 0000000000000040 RSI: 0000000000000029 RDI: 0000000000000003 RBP: 00000000006ce800 R08: 00000000000003b8 R09: 0000000000004000 R10: 00000000006ce7a0 R11: 0000000000000206 R12: 00007ffe832c5530 R13: 00000000006d09c0 R14: 0000000000000003 R15: 0000000000000029