[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c.
[   58.872805][   T27] audit: type=1800 audit(1582875902.104:25): pid=8960 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0
[   58.892439][   T27] audit: type=1800 audit(1582875902.104:26): pid=8960 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0
[   58.912650][   T27] audit: type=1800 audit(1582875902.114:27): pid=8960 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0
[....] Starting periodic command scheduler: cron[?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 '10.128.0.28' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   69.692586][ T9110] iwpm_register_pid: Unable to send a nlmsg (client = 2)
[   69.703072][ T9110] infiniband syz1: RDMA CMA: cma_listen_on_dev, error -98
[   69.720180][ T9110] netlink: 'syz-executor036': attribute type 1 has an invalid length.
[   69.763934][ T9110] 8021q: adding VLAN 0 to HW filter on device bond1
[   69.822637][ T9110] bond1: (slave gretap1): making interface the new active one
[   69.831074][ T9110] 
[   69.833429][ T9110] ======================================================
[   69.840447][ T9110] WARNING: possible circular locking dependency detected
[   69.847656][ T9110] 5.6.0-rc3-syzkaller #0 Not tainted
[   69.852941][ T9110] ------------------------------------------------------
[   69.860104][ T9110] syz-executor036/9110 is trying to acquire lock:
[   69.866511][ T9110] ffffffff89543120 (lock#3){+.+.}, at: cma_netdev_callback+0xfd/0x590
[   69.874814][ T9110] 
[   69.874814][ T9110] but task is already holding lock:
[   69.882185][ T9110] ffffffff89590da0 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x83c/0xd40
[   69.890610][ T9110] 
[   69.890610][ T9110] which lock already depends on the new lock.
[   69.890610][ T9110] 
[   69.901021][ T9110] 
[   69.901021][ T9110] the existing dependency chain (in reverse order) is:
[   69.910203][ T9110] 
[   69.910203][ T9110] -> #1 (rtnl_mutex){+.+.}:
[   69.916897][ T9110]        lock_acquire+0x154/0x250
[   69.922176][ T9110]        __mutex_lock_common+0x16e/0x2f30
[   69.927906][ T9110]        mutex_lock_nested+0x1b/0x30
[   69.933200][ T9110]        rtnl_lock+0x17/0x20
[   69.937796][ T9110]        siw_create_listen+0x93a/0xdb0
[   69.943268][ T9110]        iw_cm_listen+0x3c9/0x4a0
[   69.948309][ T9110]        rdma_listen+0x698/0x9a0
[   69.953360][ T9110]        cma_listen_on_dev+0x678/0x8e0
[   69.958827][ T9110]        cma_add_one+0x5ef/0x6f0
[   69.963879][ T9110]        add_client_context+0x482/0x660
[   69.969637][ T9110]        enable_device_and_get+0x15b/0x370
[   69.975458][ T9110]        ib_register_device+0x124d/0x15b0
[   69.981484][ T9110]        siw_newlink+0xab9/0xfb0
[   69.986431][ T9110]        nldev_newlink+0x403/0x4a0
[   69.991549][ T9110]        rdma_nl_rcv+0x701/0xa20
[   69.996639][ T9110]        netlink_unicast+0x766/0x920
[   70.002123][ T9110]        netlink_sendmsg+0xa2b/0xd40
[   70.007558][ T9110]        ____sys_sendmsg+0x4f7/0x7f0
[   70.012848][ T9110]        __sys_sendmsg+0x1ed/0x290
[   70.017977][ T9110]        __x64_sys_sendmsg+0x7f/0x90
[   70.023372][ T9110]        do_syscall_64+0xf7/0x1c0
[   70.028412][ T9110]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   70.034825][ T9110] 
[   70.034825][ T9110] -> #0 (lock#3){+.+.}:
[   70.041297][ T9110]        validate_chain+0x1507/0x7be0
[   70.046846][ T9110]        __lock_acquire+0xc5a/0x1bc0
[   70.052151][ T9110]        lock_acquire+0x154/0x250
[   70.057263][ T9110]        __mutex_lock_common+0x16e/0x2f30
[   70.063009][ T9110]        mutex_lock_nested+0x1b/0x30
[   70.068426][ T9110]        cma_netdev_callback+0xfd/0x590
[   70.073985][ T9110]        raw_notifier_call_chain+0xe3/0x190
[   70.080003][ T9110]        call_netdevice_notifiers+0xf6/0x150
[   70.086083][ T9110]        bond_change_active_slave+0x1f32/0x2b20
[   70.092649][ T9110]        bond_select_active_slave+0x584/0xa80
[   70.098726][ T9110]        bond_enslave+0x42af/0x59c0
[   70.104159][ T9110]        rtnl_newlink+0x182f/0x1c00
[   70.109504][ T9110]        rtnetlink_rcv_msg+0x889/0xd40
[   70.115118][ T9110]        netlink_rcv_skb+0x19e/0x3e0
[   70.120411][ T9110]        rtnetlink_rcv+0x1c/0x20
[   70.125368][ T9110]        netlink_unicast+0x766/0x920
[   70.130760][ T9110]        netlink_sendmsg+0xa2b/0xd40
[   70.136155][ T9110]        ____sys_sendmsg+0x4f7/0x7f0
[   70.141465][ T9110]        __sys_sendmsg+0x1ed/0x290
[   70.146853][ T9110]        __x64_sys_sendmsg+0x7f/0x90
[   70.152261][ T9110]        do_syscall_64+0xf7/0x1c0
[   70.157299][ T9110]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   70.163821][ T9110] 
[   70.163821][ T9110] other info that might help us debug this:
[   70.163821][ T9110] 
[   70.174247][ T9110]  Possible unsafe locking scenario:
[   70.174247][ T9110] 
[   70.182266][ T9110]        CPU0                    CPU1
[   70.187637][ T9110]        ----                    ----
[   70.193005][ T9110]   lock(rtnl_mutex);
[   70.196988][ T9110]                                lock(lock#3);
[   70.203145][ T9110]                                lock(rtnl_mutex);
[   70.209875][ T9110]   lock(lock#3);
[   70.213506][ T9110] 
[   70.213506][ T9110]  *** DEADLOCK ***
[   70.213506][ T9110] 
[   70.221659][ T9110] 1 lock held by syz-executor036/9110:
[   70.227123][ T9110]  #0: ffffffff89590da0 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x83c/0xd40
[   70.235996][ T9110] 
[   70.235996][ T9110] stack backtrace:
[   70.241893][ T9110] CPU: 1 PID: 9110 Comm: syz-executor036 Not tainted 5.6.0-rc3-syzkaller #0
[   70.250844][ T9110] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   70.260904][ T9110] Call Trace:
[   70.264201][ T9110]  dump_stack+0x1fb/0x318
[   70.268554][ T9110]  print_circular_bug+0xc3f/0xe70
[   70.273601][ T9110]  ? stack_trace_save+0xb1/0x150
[   70.278562][ T9110]  ? save_trace+0x4b/0x9f0
[   70.283132][ T9110]  check_noncircular+0x206/0x3a0
[   70.288095][ T9110]  validate_chain+0x1507/0x7be0
[   70.292970][ T9110]  ? __kasan_check_read+0x11/0x20
[   70.298003][ T9110]  ? mark_lock+0x107/0x1650
[   70.302539][ T9110]  ? check_preemption_disabled+0x44/0x260
[   70.308280][ T9110]  ? debug_smp_processor_id+0x9/0x20
[   70.313582][ T9110]  ? __kasan_check_write+0x14/0x20
[   70.318712][ T9110]  __lock_acquire+0xc5a/0x1bc0
[   70.323514][ T9110]  ? trace_lock_acquire+0x15b/0x1d0
[   70.328752][ T9110]  lock_acquire+0x154/0x250
[   70.333271][ T9110]  ? cma_netdev_callback+0xfd/0x590
[   70.338662][ T9110]  ? cma_netdev_callback+0xfd/0x590
[   70.344081][ T9110]  __mutex_lock_common+0x16e/0x2f30
[   70.349295][ T9110]  ? cma_netdev_callback+0xfd/0x590
[   70.354505][ T9110]  ? lockdep_hardirqs_on+0x4a5/0x7a0
[   70.359809][ T9110]  ? cfg80211_netdev_notifier_call+0x15f/0x12b0
[   70.366082][ T9110]  mutex_lock_nested+0x1b/0x30
[   70.370853][ T9110]  cma_netdev_callback+0xfd/0x590
[   70.375925][ T9110]  raw_notifier_call_chain+0xe3/0x190
[   70.381312][ T9110]  call_netdevice_notifiers+0xf6/0x150
[   70.386905][ T9110]  bond_change_active_slave+0x1f32/0x2b20
[   70.392643][ T9110]  ? trace_hardirqs_on+0x74/0x80
[   70.397755][ T9110]  ? mod_delayed_work_on+0x140/0x180
[   70.403080][ T9110]  bond_select_active_slave+0x584/0xa80
[   70.408644][ T9110]  bond_enslave+0x42af/0x59c0
[   70.413349][ T9110]  ? rtmsg_ifinfo+0xe6/0x120
[   70.417966][ T9110]  ? __dev_notify_flags+0x33c/0x4d0
[   70.423179][ T9110]  ? __kasan_check_read+0x11/0x20
[   70.428323][ T9110]  ? mutex_is_locked+0x12/0x40
[   70.433096][ T9110]  ? rtnl_is_locked+0x15/0x20
[   70.437784][ T9110]  rtnl_newlink+0x182f/0x1c00
[   70.442663][ T9110]  ? __mutex_lock_common+0x1907/0x2f30
[   70.448134][ T9110]  ? rtnetlink_rcv_msg+0x83c/0xd40
[   70.453265][ T9110]  ? rtnl_setlink+0x490/0x490
[   70.457968][ T9110]  rtnetlink_rcv_msg+0x889/0xd40
[   70.462941][ T9110]  ? rcu_lock_release+0x9/0x30
[   70.467838][ T9110]  netlink_rcv_skb+0x19e/0x3e0
[   70.472758][ T9110]  ? rtnetlink_bind+0x80/0x80
[   70.477447][ T9110]  rtnetlink_rcv+0x1c/0x20
[   70.481870][ T9110]  netlink_unicast+0x766/0x920
[   70.486636][ T9110]  netlink_sendmsg+0xa2b/0xd40
[   70.491507][ T9110]  ? netlink_getsockopt+0x9f0/0x9f0
[   70.496716][ T9110]  ____sys_sendmsg+0x4f7/0x7f0
[   70.501498][ T9110]  __sys_sendmsg+0x1ed/0x290
[   70.506116][ T9110]  ? rcu_read_lock_sched_held+0x10b/0x170
[   70.511844][ T9110]  ? __kasan_check_write+0x14/0x20
[   70.516966][ T9110]  ? __fpregs_load_activate+0x194/0x220
[   70.522538][ T9110]  ? switch_fpu_return+0xe/0x10
[   70.527396][ T9110]  ? prepare_exit_to_usermode+0x221/0x5b0
[   70.533255][ T9110]  ? trace_irq_disable_rcuidle+0x23/0x1e0
[   70.538988][ T9110]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[   70.544641][ T9110]  ? trace_irq_disable_rcuidle+0x23/0x1e0
[   70.550372][ T9110]  ? do_syscall_64+0x1d/0x1c0
[   70.555066][ T9110]  __x64_sys_sendmsg+0x7f/0x90
[   70.559842][ T9110]  do_syscall_64+0xf7/0x1c0
[   70.564354][ T9110]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   70.570347][ T9110] RIP: 0033:0x440509
[   70.574242][ T9110] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
[   70.593854][ T9110] RSP: 002b:00007ffc21dab118 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[   70.602375][ T9110] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440509
[   70.610349][ T9110] RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000000000004
[   70.618325][ T9110] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
[