[....] Starting enhanced syslogd: rsyslogd[   12.686068] audit: type=1400 audit(1539195465.812:4): avc:  denied  { syslog } for  pid=1924 comm="rsyslogd" capability=34  scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=capability2 permissive=1
[?25l[?1c7[ ok 8[?25h[?0c.
[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c.
Starting mcstransd: 
[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c.
[....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c.

Debian GNU/Linux 7 syzkaller ttyS0

Warning: Permanently added '10.128.0.111' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   45.909925] 
[   45.911574] ======================================================
[   45.917865] [ INFO: possible circular locking dependency detected ]
[   45.924246] 4.4.159+ #44 Not tainted
[   45.927981] -------------------------------------------------------
[   45.934462] syz-executor376/2088 is trying to acquire lock:
[   45.940326]  (rtnl_mutex){+.+.+.}, at: [<ffffffff82259d67>] rtnl_lock+0x17/0x20
[   45.948246] 
[   45.948246] but task is already holding lock:
[   45.954197]  (sk_lock-AF_INET6){+.+.+.}, at: [<ffffffff825ea752>] do_ipv6_setsockopt.isra.4+0x252/0x2d50
[   45.964281] 
[   45.964281] which lock already depends on the new lock.
[   45.964281] 
[   45.972575] 
[   45.972575] the existing dependency chain (in reverse order) is:
[   45.980237] 
-> #1 (sk_lock-AF_INET6){+.+.+.}:
[   45.985369]        [<ffffffff81202efe>] lock_acquire+0x15e/0x450
[   45.991790]        [<ffffffff821cfb56>] lock_sock_nested+0xc6/0x120
[   45.998462]        [<ffffffff825ea6d2>] do_ipv6_setsockopt.isra.4+0x1d2/0x2d50
[   46.005929]        [<ffffffff825ed2e7>] ipv6_setsockopt+0x97/0x130
[   46.012357]        [<ffffffff822960b8>] compat_mc_setsockopt+0x278/0x6e0
[   46.019294]        [<ffffffff825ed4a6>] compat_ipv6_setsockopt+0x126/0x1d0
[   46.026407]        [<ffffffff826021ea>] compat_udpv6_setsockopt+0x4a/0x90
[   46.033430]        [<ffffffff821c9e54>] compat_sock_common_setsockopt+0xb4/0x150
[   46.041235]        [<ffffffff822982d9>] compat_SyS_setsockopt+0x169/0x700
[   46.048263]        [<ffffffff8100629e>] do_fast_syscall_32+0x31e/0xa80
[   46.055032]        [<ffffffff82707410>] sysenter_flags_fixed+0xd/0x1a
[   46.061715] 
-> #0 (rtnl_mutex){+.+.+.}:
[   46.066314]        [<ffffffff811ff31c>] __lock_acquire+0x3e6c/0x5f10
[   46.072902]        [<ffffffff81202efe>] lock_acquire+0x15e/0x450
[   46.079146]        [<ffffffff826fa74b>] mutex_lock_nested+0xbb/0x8d0
[   46.085751]        [<ffffffff82259d67>] rtnl_lock+0x17/0x20
[   46.091622]        [<ffffffff8262489e>] ipv6_sock_mc_close+0x10e/0x350
[   46.098392]        [<ffffffff825eb207>] do_ipv6_setsockopt.isra.4+0xd07/0x2d50
[   46.106005]        [<ffffffff825ed469>] compat_ipv6_setsockopt+0xe9/0x1d0
[   46.113048]        [<ffffffff826021ea>] compat_udpv6_setsockopt+0x4a/0x90
[   46.120251]        [<ffffffff821c9e54>] compat_sock_common_setsockopt+0xb4/0x150
[   46.127908]        [<ffffffff822982d9>] compat_SyS_setsockopt+0x169/0x700
[   46.134951]        [<ffffffff8100629e>] do_fast_syscall_32+0x31e/0xa80
[   46.141824]        [<ffffffff82707410>] sysenter_flags_fixed+0xd/0x1a
[   46.148503] 
[   46.148503] other info that might help us debug this:
[   46.148503] 
[   46.156625]  Possible unsafe locking scenario:
[   46.156625] 
[   46.162666]        CPU0                    CPU1
[   46.167321]        ----                    ----
[   46.171963]   lock(sk_lock-AF_INET6);
[   46.175979]                                lock(rtnl_mutex);
[   46.182448]                                lock(sk_lock-AF_INET6);
[   46.189088]   lock(rtnl_mutex);
[   46.192580] 
[   46.192580]  *** DEADLOCK ***
[   46.192580] 
[   46.198624] 1 lock held by syz-executor376/2088:
[   46.203356]  #0:  (sk_lock-AF_INET6){+.+.+.}, at: [<ffffffff825ea752>] do_ipv6_setsockopt.isra.4+0x252/0x2d50
[   46.214128] 
[   46.214128] stack backtrace:
[   46.218609] CPU: 0 PID: 2088 Comm: syz-executor376 Not tainted 4.4.159+ #44
[   46.225696]  0000000000000000 71bda4cb28f1b408 ffff8801cf507538 ffffffff81a994bd
[   46.233716]  ffffffff83a85b10 ffffffff83ac5140 ffffffff83a85b10 ffff8801d52b08e8
[   46.241723]  ffff8801d52b0000 ffff8801cf507580 ffffffff813a84ea 0000000000000001
[   46.249714] Call Trace:
[   46.252284]  [<ffffffff81a994bd>] dump_stack+0xc1/0x124
[   46.257629]  [<ffffffff813a84ea>] print_circular_bug.cold.34+0x2f7/0x432
[   46.264451]  [<ffffffff811ff31c>] __lock_acquire+0x3e6c/0x5f10
[   46.270401]  [<ffffffff81237987>] ? debug_lockdep_rcu_enabled+0x77/0x90
[   46.277135]  [<ffffffff811fb4b0>] ? trace_hardirqs_on+0x10/0x10
[   46.283292]  [<ffffffff8261943b>] ? ip6_mc_add_src+0x79b/0xbb0
[   46.289315]  [<ffffffff81202efe>] lock_acquire+0x15e/0x450
[   46.294925]  [<ffffffff82259d67>] ? rtnl_lock+0x17/0x20
[   46.300268]  [<ffffffff82259d67>] ? rtnl_lock+0x17/0x20
[   46.305685]  [<ffffffff826fa74b>] mutex_lock_nested+0xbb/0x8d0
[   46.311663]  [<ffffffff82259d67>] ? rtnl_lock+0x17/0x20
[   46.317013]  [<ffffffff82705100>] ? _raw_spin_unlock_bh+0x30/0x40
[   46.323227]  [<ffffffff81237987>] ? debug_lockdep_rcu_enabled+0x77/0x90
[   46.329959]  [<ffffffff826fa690>] ? mutex_trylock+0x3e0/0x3e0
[   46.335824]  [<ffffffff811faea7>] ? mark_held_locks+0xc7/0x130
[   46.341924]  [<ffffffff810e1d1a>] ? __local_bh_enable_ip+0x6a/0xd0
[   46.348231]  [<ffffffff82259d67>] rtnl_lock+0x17/0x20
[   46.353408]  [<ffffffff8262489e>] ipv6_sock_mc_close+0x10e/0x350
[   46.359535]  [<ffffffff8264ff37>] ? fl6_free_socklist+0xb7/0x240
[   46.365671]  [<ffffffff825eb207>] do_ipv6_setsockopt.isra.4+0xd07/0x2d50
[   46.372495]  [<ffffffff825ea500>] ? ip6_ra_control+0x430/0x430
[   46.378445]  [<ffffffff811fb4b0>] ? trace_hardirqs_on+0x10/0x10
[   46.384487]  [<ffffffff811fbf35>] ? __lock_acquire+0xa85/0x5f10
[   46.390588]  [<ffffffff81237987>] ? debug_lockdep_rcu_enabled+0x77/0x90
[   46.397351]  [<ffffffff819423aa>] ? avc_has_perm+0x15a/0x3a0
[   46.403235]  [<ffffffff8194241c>] ? avc_has_perm+0x1cc/0x3a0
[   46.409125]  [<ffffffff819422ee>] ? avc_has_perm+0x9e/0x3a0
[   46.414819]  [<ffffffff81942250>] ? avc_has_perm_noaudit+0x2f0/0x2f0
[   46.421293]  [<ffffffff81af752b>] ? check_preemption_disabled+0x3b/0x170
[   46.428117]  [<ffffffff8194aac1>] ? sock_has_perm+0x1c1/0x3f0
[   46.433997]  [<ffffffff8194aba1>] ? sock_has_perm+0x2a1/0x3f0
[   46.439867]  [<ffffffff8194a99f>] ? sock_has_perm+0x9f/0x3f0
[   46.445650]  [<ffffffff8194a900>] ? selinux_msg_queue_alloc_security+0x2e0/0x2e0
[   46.453170]  [<ffffffff814eaa8f>] ? __fget+0x12f/0x3d0
[   46.458435]  [<ffffffff825ed469>] compat_ipv6_setsockopt+0xe9/0x1d0
[   46.464932]  [<ffffffff826021ea>] compat_udpv6_setsockopt+0x4a/0x90
[   46.471324]  [<ffffffff821c9e54>] compat_sock_common_setsockopt+0xb4/0x150
[   46.478320]  [<ffffffff826021a0>] ? udpv6_setsockopt+0x90/0x90
[   46.484281]  [<ffffffff822982d9>] compat_SyS_setsockopt+0x169/0x700
[   46.490683]  [<ffffffff821c9da0>] ? sock_common_setsockopt+0xe0/0xe0
[   46.497169]  [<ffffffff82298170>] ? scm_detach_fds_compat+0x3b0/0x3b0
[   46.503737]  [<ffffffff810ab716>] ? __do_page_fault+0x2b6/0x7e0
[   46.509776]  [<ffffffff8100605