audit: type=1400 audit(1560636295.335:443): avc:  denied  { relabelto } for  pid=32281 comm="syz-executor.1" name="" dev="pipefs" ino=111304 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:scsi_generic_device_t:s0 tclass=fifo_file permissive=1
===============================
[ INFO: suspicious RCU usage. ]
4.4.174+ #4 Not tainted
-------------------------------
net/ipv4/xfrm4_protocol.c:80 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 1, debug_locks = 0
no locks held by syz-executor.1/32282.

stack backtrace:
CPU: 0 PID: 32282 Comm: syz-executor.1 Not tainted 4.4.174+ #4
 0000000000000000 632c4c18f2f7f977 ffff8801d9147778 ffffffff81aad1a1
 ffffffff831af4e0 0000000000000000 0000000000000001 0000000000000050
 ffff8801bd0517c0 ffff8801d91477a8 ffffffff813ab7d6 ffff8801d43948c0
Call Trace:
 [<ffffffff81aad1a1>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81aad1a1>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<ffffffff813ab7d6>] lockdep_rcu_suspicious.cold+0x10a/0x149 kernel/locking/lockdep.c:4305
 [<ffffffff8254222a>] xfrm4_rcv_encap+0x30a/0x370 net/ipv4/xfrm4_protocol.c:80
 [<ffffffff82540745>] xfrm4_udp_encap_rcv+0x3f5/0x620 net/ipv4/xfrm4_input.c:148
 [<ffffffff82482087>] udp_queue_rcv_skb+0xe57/0x14e0 net/ipv4/udp.c:1547
 [<ffffffff821e5e40>] sk_backlog_rcv include/net/sock.h:875 [inline]
 [<ffffffff821e5e40>] __release_sock net/core/sock.c:2024 [inline]
 [<ffffffff821e5e40>] release_sock+0x170/0x500 net/core/sock.c:2477
 [<ffffffff8247f646>] udp_sendmsg+0x1176/0x1c60 net/ipv4/udp.c:1107
 [<ffffffff824a8b42>] inet_sendmsg+0x202/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff821d838e>] sock_sendmsg_nosec net/socket.c:638 [inline]
 [<ffffffff821d838e>] sock_sendmsg+0xbe/0x110 net/socket.c:648
 [<ffffffff821da269>] ___sys_sendmsg+0x769/0x890 net/socket.c:1975
 [<ffffffff821dd0c5>] __sys_sendmsg+0xc5/0x160 net/socket.c:2009
 [<ffffffff821dd18d>] SYSC_sendmsg net/socket.c:2020 [inline]
 [<ffffffff821dd18d>] SyS_sendmsg+0x2d/0x50 net/socket.c:2016
 [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a