[ OK ] Started Getty on tty4. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Started Serial Getty on ttyS0. [ OK ] Started Getty on tty1. [ 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... Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.239' (ECDSA) to the list of known hosts. 2020/04/21 11:38:31 fuzzer started 2020/04/21 11:38:32 connecting to host at 10.128.0.26:42349 2020/04/21 11:38:32 checking machine... 2020/04/21 11:38:32 checking revisions... 2020/04/21 11:38:32 testing simple program... syzkaller login: [ 65.872804][ T6876] IPVS: ftp: loaded support on port[0] = 21 2020/04/21 11:38:33 building call list... [ 66.218804][ T100] tipc: TX() has been purged, node left! [ 66.261820][ T100] [ 66.264302][ T100] ============================= [ 66.269444][ T100] WARNING: suspicious RCU usage [ 66.274451][ T100] 5.7.0-rc2-next-20200421-syzkaller #0 Not tainted [ 66.281134][ T100] ----------------------------- [ 66.286106][ T100] net/ipv4/ipmr.c:1757 RCU-list traversed in non-reader section!! [ 66.294635][ T100] [ 66.294635][ T100] other info that might help us debug this: [ 66.294635][ T100] [ 66.305433][ T100] [ 66.305433][ T100] rcu_scheduler_active = 2, debug_locks = 1 [ 66.314334][ T100] 4 locks held by kworker/u4:3/100: [ 66.319883][ T100] #0: ffff8880a9772138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x844/0x16a0 [ 66.330550][ T100] #1: ffffc90000e27dc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x878/0x16a0 [ 66.341830][ T100] #2: ffffffff8a5a2b70 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xa50 [ 66.351514][ T100] #3: ffffffff8a5aeae8 (rtnl_mutex){+.+.}-{3:3}, at: ip6gre_exit_batch_net+0x88/0x700 [ 66.388492][ T100] [ 66.388492][ T100] stack backtrace: [ 66.395205][ T100] CPU: 0 PID: 100 Comm: kworker/u4:3 Not tainted 5.7.0-rc2-next-20200421-syzkaller #0 [ 66.404777][ T100] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 66.415604][ T100] Workqueue: netns cleanup_net [ 66.420494][ T100] Call Trace: [ 66.423794][ T100] dump_stack+0x188/0x20d [ 66.428129][ T100] ipmr_device_event+0x240/0x2b0 [ 66.433067][ T100] ? __sanitizer_cov_trace_switch+0x45/0x70 [ 66.438988][ T100] notifier_call_chain+0xc0/0x230 [ 66.444393][ T100] call_netdevice_notifiers_info+0xb5/0x130 [ 66.450305][ T100] rollback_registered_many+0x75c/0xe70 [ 66.455911][ T100] ? netif_set_real_num_tx_queues+0x700/0x700 [ 66.462029][ T100] ? lock_downgrade+0x840/0x840 [ 66.467257][ T100] unregister_netdevice_many.part.0+0x16/0x1e0 [ 66.473429][ T100] unregister_netdevice_many+0x36/0x50 [ 66.479212][ T100] ip6gre_exit_batch_net+0x4e8/0x700 [ 66.484520][ T100] ? ip6gre_tunnel_link+0xf0/0xf0 [ 66.489567][ T100] ? rcu_read_lock_held_common+0x130/0x130 [ 66.495391][ T100] ? ip6gre_tunnel_link+0xf0/0xf0 [ 66.500440][ T100] ops_exit_list.isra.0+0x103/0x150 [ 66.505656][ T100] cleanup_net+0x511/0xa50 [ 66.510119][ T100] ? unregister_pernet_device+0x70/0x70 [ 66.515673][ T100] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 66.521657][ T100] ? _raw_spin_unlock_irq+0x1f/0x80 [ 66.526895][ T100] process_one_work+0x965/0x16a0 [ 66.531870][ T100] ? lock_release+0x800/0x800 [ 66.536572][ T100] ? pwq_dec_nr_in_flight+0x310/0x310 [ 66.542056][ T100] ? rwlock_bug.part.0+0x90/0x90 [ 66.547033][ T100] worker_thread+0x96/0xe20 [ 66.551554][ T100] ? process_one_work+0x16a0/0x16a0 [ 66.556754][ T100] kthread+0x38b/0x470 [ 66.560830][ T100] ? kthread_mod_delayed_work+0x1a0/0x1a0 [ 66.566556][ T100] ret_from_fork+0x24/0x30 [ 67.733172][ T6904] can: request_module (can-proto-0) failed. executing program [ 69.825249][ T6904] can: request_module (can-proto-0) failed. [ 69.837016][ T6904] can: request_module (can-proto-0) failed.