[ OK ] Started Serial Getty on ttyS0. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Update UTMP about System Runlevel Changes. [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.151' (ECDSA) to the list of known hosts. 2020/04/21 06:49:56 fuzzer started 2020/04/21 06:49:58 connecting to host at 10.128.0.26:44249 2020/04/21 06:49:58 checking machine... 2020/04/21 06:49:58 checking revisions... 2020/04/21 06:49:58 testing simple program... syzkaller login: [ 60.770004][ T6865] IPVS: ftp: loaded support on port[0] = 21 2020/04/21 06:49:58 building call list... [ 61.141399][ T7] tipc: TX() has been purged, node left! [ 61.184038][ T7] [ 61.186468][ T7] ============================= [ 61.192665][ T7] WARNING: suspicious RCU usage [ 61.197702][ T7] 5.7.0-rc2-next-20200421-syzkaller #0 Not tainted [ 61.205921][ T7] ----------------------------- [ 61.210839][ T7] net/ipv4/ipmr.c:1757 RCU-list traversed in non-reader section!! [ 61.220958][ T7] [ 61.220958][ T7] other info that might help us debug this: [ 61.220958][ T7] [ 61.232316][ T7] [ 61.232316][ T7] rcu_scheduler_active = 2, debug_locks = 1 [ 61.240518][ T7] 4 locks held by kworker/u4:0/7: [ 61.247798][ T7] #0: ffff8880a9772138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x844/0x16a0 [ 61.259228][ T7] #1: ffffc90000cdfdc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x878/0x16a0 [ 61.270172][ T7] #2: ffffffff8a5a2b70 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xa50 [ 61.281679][ T7] #3: ffffffff8a5aeae8 (rtnl_mutex){+.+.}-{3:3}, at: ip6gre_exit_batch_net+0x88/0x700 [ 61.292502][ T7] [ 61.292502][ T7] stack backtrace: [ 61.298448][ T7] CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 5.7.0-rc2-next-20200421-syzkaller #0 [ 61.307805][ T7] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 61.317865][ T7] Workqueue: netns cleanup_net [ 61.322634][ T7] Call Trace: [ 61.325932][ T7] dump_stack+0x188/0x20d [ 61.330274][ T7] ipmr_device_event+0x240/0x2b0 [ 61.335212][ T7] ? __sanitizer_cov_trace_switch+0x45/0x70 [ 61.341120][ T7] notifier_call_chain+0xc0/0x230 [ 61.346169][ T7] call_netdevice_notifiers_info+0xb5/0x130 [ 61.352067][ T7] rollback_registered_many+0x75c/0xe70 [ 61.357623][ T7] ? netif_set_real_num_tx_queues+0x700/0x700 [ 61.364431][ T7] ? lock_downgrade+0x840/0x840 [ 61.369335][ T7] unregister_netdevice_many.part.0+0x16/0x1e0 [ 61.375497][ T7] unregister_netdevice_many+0x36/0x50 [ 61.380959][ T7] ip6gre_exit_batch_net+0x4e8/0x700 [ 61.386248][ T7] ? ip6gre_tunnel_link+0xf0/0xf0 [ 61.391297][ T7] ? rcu_read_lock_held_common+0x130/0x130 [ 61.397126][ T7] ? ip6gre_tunnel_link+0xf0/0xf0 [ 61.402150][ T7] ops_exit_list.isra.0+0x103/0x150 [ 61.407369][ T7] cleanup_net+0x511/0xa50 [ 61.411793][ T7] ? unregister_pernet_device+0x70/0x70 [ 61.417355][ T7] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 61.423346][ T7] ? _raw_spin_unlock_irq+0x1f/0x80 [ 61.428545][ T7] process_one_work+0x965/0x16a0 [ 61.433507][ T7] ? lock_release+0x800/0x800 [ 61.438181][ T7] ? pwq_dec_nr_in_flight+0x310/0x310 [ 61.443552][ T7] ? rwlock_bug.part.0+0x90/0x90 [ 61.448496][ T7] worker_thread+0x96/0xe20 [ 61.453017][ T7] ? process_one_work+0x16a0/0x16a0 [ 61.458212][ T7] kthread+0x38b/0x470 [ 61.462282][ T7] ? kthread_mod_delayed_work+0x1a0/0x1a0 [ 61.467999][ T7] ret_from_fork+0x24/0x30 [ 62.682682][ T6852] can: request_module (can-proto-0) failed. executing program [ 64.625973][ T6852] can: request_module (can-proto-0) failed. [ 64.637874][ T6852] can: request_module (can-proto-0) failed.