[ OK ] Started System Logging Service. [ OK ] Started OpenBSD Secure Shell server. [ OK ] Started getty on tty2-tty6 if dbus and logind are not available. [ OK ] Started Getty on tty6. [ OK ] Started Getty on tty5. [ OK ] Started Getty on tty4. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. Starting Load/Save RF Kill Switch Status... [ 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 Load/Save RF Kill Switch Status. [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.10.57' (ECDSA) to the list of known hosts. 2020/04/21 06:49:46 fuzzer started 2020/04/21 06:49:48 connecting to host at 10.128.0.26:43771 2020/04/21 06:49:48 checking machine... 2020/04/21 06:49:48 checking revisions... 2020/04/21 06:49:48 testing simple program... syzkaller login: [ 59.849452][ T6856] IPVS: ftp: loaded support on port[0] = 21 2020/04/21 06:49:48 building call list... [ 60.175738][ T21] tipc: TX() has been purged, node left! [ 60.218089][ T21] [ 60.220538][ T21] ============================= [ 60.225373][ T21] WARNING: suspicious RCU usage [ 60.233378][ T21] 5.7.0-rc2-next-20200421-syzkaller #0 Not tainted [ 60.240675][ T21] ----------------------------- [ 60.246614][ T21] net/ipv4/ipmr.c:1757 RCU-list traversed in non-reader section!! [ 60.254478][ T21] [ 60.254478][ T21] other info that might help us debug this: [ 60.254478][ T21] [ 60.267334][ T21] [ 60.267334][ T21] rcu_scheduler_active = 2, debug_locks = 1 [ 60.275890][ T21] 4 locks held by kworker/u4:1/21: [ 60.281183][ T21] #0: ffff8880a9772138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x844/0x16a0 [ 60.291947][ T21] #1: ffffc90000dd7dc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x878/0x16a0 [ 60.302563][ T21] #2: ffffffff8a5a2b70 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xa50 [ 60.312537][ T21] #3: ffffffff8a5aeae8 (rtnl_mutex){+.+.}-{3:3}, at: ip6gre_exit_batch_net+0x88/0x700 [ 60.323931][ T21] [ 60.323931][ T21] stack backtrace: [ 60.330480][ T21] CPU: 1 PID: 21 Comm: kworker/u4:1 Not tainted 5.7.0-rc2-next-20200421-syzkaller #0 [ 60.340475][ T21] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 60.350531][ T21] Workqueue: netns cleanup_net [ 60.355284][ T21] Call Trace: [ 60.358571][ T21] dump_stack+0x188/0x20d [ 60.363165][ T21] ipmr_device_event+0x240/0x2b0 [ 60.368096][ T21] ? __sanitizer_cov_trace_switch+0x45/0x70 [ 60.373987][ T21] notifier_call_chain+0xc0/0x230 [ 60.379014][ T21] call_netdevice_notifiers_info+0xb5/0x130 [ 60.384905][ T21] rollback_registered_many+0x75c/0xe70 [ 60.390452][ T21] ? netif_set_real_num_tx_queues+0x700/0x700 [ 60.396524][ T21] ? lock_downgrade+0x840/0x840 [ 60.401383][ T21] unregister_netdevice_many.part.0+0x16/0x1e0 [ 60.407534][ T21] unregister_netdevice_many+0x36/0x50 [ 60.412991][ T21] ip6gre_exit_batch_net+0x4e8/0x700 [ 60.418280][ T21] ? ip6gre_tunnel_link+0xf0/0xf0 [ 60.423309][ T21] ? rcu_read_lock_held_common+0x130/0x130 [ 60.429113][ T21] ? ip6gre_tunnel_link+0xf0/0xf0 [ 60.434396][ T21] ops_exit_list.isra.0+0x103/0x150 [ 60.439606][ T21] cleanup_net+0x511/0xa50 [ 60.444280][ T21] ? unregister_pernet_device+0x70/0x70 [ 60.450085][ T21] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 60.456058][ T21] ? _raw_spin_unlock_irq+0x1f/0x80 [ 60.461254][ T21] process_one_work+0x965/0x16a0 [ 60.466195][ T21] ? lock_release+0x800/0x800 [ 60.470952][ T21] ? pwq_dec_nr_in_flight+0x310/0x310 [ 60.476408][ T21] ? rwlock_bug.part.0+0x90/0x90 [ 60.481349][ T21] worker_thread+0x96/0xe20 [ 60.487111][ T21] ? process_one_work+0x16a0/0x16a0 [ 60.492314][ T21] kthread+0x38b/0x470 [ 60.496374][ T21] ? kthread_mod_delayed_work+0x1a0/0x1a0 [ 60.502082][ T21] ret_from_fork+0x24/0x30 [ 61.676413][ T6839] can: request_module (can-proto-0) failed. executing program [ 63.752049][ T6839] can: request_module (can-proto-0) failed. [ 63.763358][ T6839] can: request_module (can-proto-0) failed.