[ OK ] Started Getty on tty4. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Started Getty on tty1. [ OK ] Started Serial Getty on ttyS0. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.235' (ECDSA) to the list of known hosts. 2020/04/21 11:38:25 fuzzer started 2020/04/21 11:38:27 connecting to host at 10.128.0.26:36341 2020/04/21 11:38:27 checking machine... 2020/04/21 11:38:27 checking revisions... 2020/04/21 11:38:27 testing simple program... syzkaller login: [ 60.318968][ T6851] IPVS: ftp: loaded support on port[0] = 21 2020/04/21 11:38:27 building call list... [ 60.654656][ T57] tipc: TX() has been purged, node left! [ 60.697426][ T57] [ 60.699976][ T57] ============================= [ 60.706307][ T57] WARNING: suspicious RCU usage [ 60.711203][ T57] 5.7.0-rc2-next-20200421-syzkaller #0 Not tainted [ 60.719114][ T57] ----------------------------- [ 60.724029][ T57] net/ipv4/ipmr.c:1757 RCU-list traversed in non-reader section!! [ 60.746301][ T57] [ 60.746301][ T57] other info that might help us debug this: [ 60.746301][ T57] [ 60.758245][ T57] [ 60.758245][ T57] rcu_scheduler_active = 2, debug_locks = 1 [ 60.767500][ T57] 4 locks held by kworker/u4:2/57: [ 60.772693][ T57] #0: ffff8880a9772138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x844/0x16a0 [ 60.784691][ T57] #1: ffffc90000f07dc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x878/0x16a0 [ 60.796630][ T57] #2: ffffffff8a5a2b70 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xa50 [ 60.807099][ T57] #3: ffffffff8a5aeae8 (rtnl_mutex){+.+.}-{3:3}, at: ip6gre_exit_batch_net+0x88/0x700 [ 60.818937][ T57] [ 60.818937][ T57] stack backtrace: [ 60.825764][ T57] CPU: 0 PID: 57 Comm: kworker/u4:2 Not tainted 5.7.0-rc2-next-20200421-syzkaller #0 [ 60.835234][ T57] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 60.845290][ T57] Workqueue: netns cleanup_net [ 60.850044][ T57] Call Trace: [ 60.853347][ T57] dump_stack+0x188/0x20d [ 60.857683][ T57] ipmr_device_event+0x240/0x2b0 [ 60.862619][ T57] ? __sanitizer_cov_trace_switch+0x45/0x70 [ 60.868533][ T57] notifier_call_chain+0xc0/0x230 [ 60.873560][ T57] call_netdevice_notifiers_info+0xb5/0x130 [ 60.879475][ T57] rollback_registered_many+0x75c/0xe70 [ 60.885026][ T57] ? netif_set_real_num_tx_queues+0x700/0x700 [ 60.891098][ T57] ? lock_downgrade+0x840/0x840 [ 60.895954][ T57] unregister_netdevice_many.part.0+0x16/0x1e0 [ 60.902105][ T57] unregister_netdevice_many+0x36/0x50 [ 60.907578][ T57] ip6gre_exit_batch_net+0x4e8/0x700 [ 60.912864][ T57] ? ip6gre_tunnel_link+0xf0/0xf0 [ 60.917908][ T57] ? rcu_read_lock_held_common+0x130/0x130 [ 60.923715][ T57] ? ip6gre_tunnel_link+0xf0/0xf0 [ 60.928734][ T57] ops_exit_list.isra.0+0x103/0x150 [ 60.933930][ T57] cleanup_net+0x511/0xa50 [ 60.938360][ T57] ? unregister_pernet_device+0x70/0x70 [ 60.943916][ T57] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 60.949922][ T57] ? _raw_spin_unlock_irq+0x1f/0x80 [ 60.955130][ T57] process_one_work+0x965/0x16a0 [ 60.960075][ T57] ? lock_release+0x800/0x800 [ 60.964752][ T57] ? pwq_dec_nr_in_flight+0x310/0x310 [ 60.970143][ T57] ? rwlock_bug.part.0+0x90/0x90 [ 60.975109][ T57] worker_thread+0x96/0xe20 [ 60.979623][ T57] ? process_one_work+0x16a0/0x16a0 [ 60.984819][ T57] kthread+0x38b/0x470 [ 60.988889][ T57] ? kthread_mod_delayed_work+0x1a0/0x1a0 [ 60.994615][ T57] ret_from_fork+0x24/0x30 [ 62.087699][ T6828] can: request_module (can-proto-0) failed. executing program [ 64.138851][ T6828] can: request_module (can-proto-0) failed. [ 64.151023][ T6828] can: request_module (can-proto-0) failed.