audit: type=1400 audit(1519103815.838:12): avc: denied { net_raw } for pid=4285 comm="syz-executor0" capability=13 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1 ===================================== WARNING: bad unlock balance detected! 4.16.0-rc1+ #232 Not tainted ------------------------------------- syz-executor0/4285 is trying to release lock (rcu_read_lock_bh) at: [] rcu_read_unlock_bh include/linux/rcupdate.h:722 [inline] [] hashlimit_mt_common.isra.10+0x1beb/0x2610 net/netfilter/xt_hashlimit.c:777 but there are no more locks to release! other info that might help us debug this: 5 locks held by syz-executor0/4285: #0: (rcu_read_lock){....}, at: [<00000000f4b1d9d8>] arch_static_branch arch/x86/include/asm/jump_label.h:36 [inline] #0: (rcu_read_lock){....}, at: [<00000000f4b1d9d8>] static_key_false include/linux/jump_label.h:142 [inline] #0: (rcu_read_lock){....}, at: [<00000000f4b1d9d8>] netif_receive_skb_internal+0xa2/0x670 net/core/dev.c:4660 #1: (rcu_read_lock){....}, at: [<000000005701b738>] read_pnet include/net/net_namespace.h:280 [inline] #1: (rcu_read_lock){....}, at: [<000000005701b738>] dev_net include/linux/netdevice.h:2056 [inline] #1: (rcu_read_lock){....}, at: [<000000005701b738>] ipv6_rcv+0x117/0x1fa0 net/ipv6/ip6_input.c:79 #2: (k-slock-AF_INET6){+...}, at: [<000000004b2f2ed6>] spin_trylock include/linux/spinlock.h:320 [inline] #2: (k-slock-AF_INET6){+...}, at: [<000000004b2f2ed6>] icmpv6_xmit_lock net/ipv6/icmp.c:119 [inline] #2: (k-slock-AF_INET6){+...}, at: [<000000004b2f2ed6>] icmp6_send+0x1250/0x2bb0 net/ipv6/icmp.c:528 #3: (rcu_read_lock){....}, at: [<000000007b4f372b>] icmp6_send+0x1d37/0x2bb0 net/ipv6/icmp.c:563 #4: (rcu_read_lock){....}, at: [<000000007f7b5117>] nf_hook include/linux/netfilter.h:206 [inline] #4: (rcu_read_lock){....}, at: [<000000007f7b5117>] __ip6_local_out+0x2f1/0xaa0 net/ipv6/output_core.c:164 stack backtrace: CPU: 1 PID: 4285 Comm: syz-executor0 Not tainted 4.16.0-rc1+ #232 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_unlock_imbalance_bug+0x12f/0x140 kernel/locking/lockdep.c:3484 __lock_release kernel/locking/lockdep.c:3691 [inline] lock_release+0x6fe/0xa40 kernel/locking/lockdep.c:3939 rcu_lock_release include/linux/rcupdate.h:249 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:724 [inline] hashlimit_mt_common.isra.10+0x1c08/0x2610 net/netfilter/xt_hashlimit.c:777 hashlimit_mt+0x78/0x90 net/netfilter/xt_hashlimit.c:846 ip6t_do_table+0x98d/0x1a30 net/ipv6/netfilter/ip6_tables.c:319 ip6table_raw_hook+0x65/0x80 net/ipv6/netfilter/ip6table_raw.c:42 nf_hook_entry_hookfn include/linux/netfilter.h:120 [inline] nf_hook_slow+0xba/0x1a0 net/netfilter/core.c:483 nf_hook include/linux/netfilter.h:243 [inline] __ip6_local_out+0x517/0xaa0 net/ipv6/output_core.c:164 ip6_local_out+0x2d/0x160 net/ipv6/output_core.c:174 ip6_send_skb+0xa1/0x330 net/ipv6/ip6_output.c:1677 ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1697 icmpv6_push_pending_frames+0x338/0x520 net/ipv6/icmp.c:288 icmp6_send+0x2244/0x2bb0 net/ipv6/icmp.c:582 icmpv6_param_prob+0x2c/0x40 net/ipv6/icmp.c:598 ip6_tlvopt_unknown net/ipv6/exthdrs.c:106 [inline] ip6_parse_tlv+0x573/0x650 net/ipv6/exthdrs.c:190 ipv6_parse_hopopts+0x246/0x530 net/ipv6/exthdrs.c:863 ipv6_rcv+0xe3b/0x1fa0 net/ipv6/ip6_input.c:196 __netif_receive_skb_core+0x1a41/0x3460 net/core/dev.c:4547 __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4612 netif_receive_skb_internal+0x10b/0x670 net/core/dev.c:4686 netif_receive_skb+0xae/0x390 net/core/dev.c:4710 tun_rx_batched.isra.52+0x5ee/0x870 drivers/net/tun.c:1560 tun_get_user+0x25de/0x3940 drivers/net/tun.c:1961 tun_chr_write_iter+0xbd/0x1c0 drivers/net/tun.c:1989 call_write_iter include/linux/fs.h:1781 [inline] do_iter_readv_writev+0x55c/0x830 fs/read_write.c:653 do_iter_write+0x154/0x540 fs/read_write.c:932 vfs_writev+0x18a/0x340 fs/read_write.c:977 do_writev+0xfc/0x2a0 fs/read_write.c:1012 SYSC_writev fs/read_write.c:1085 [inline] SyS_writev+0x27/0x30 fs/read_write.c:1082 do_syscall_64+0x282/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x26/0x9b RIP: 0033:0x453c60 RSP: 002b:0000000000a3e8f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 0000000000000046 RCX: 0000000000453c60 RDX: