[....] Starting enhanced syslogd: rsyslogd[ 14.856139] audit: type=1400 audit(1552222534.927:4): avc: denied { syslog } for pid=1925 comm="rsyslogd" capability=34 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=capability2 permissive=1 [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Starting mcstransd: [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.94' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 32.582300] netlink: 8 bytes leftover after parsing attributes in process `syz-executor734'. [ 32.652521] [ 32.654282] =============================== [ 32.658623] [ INFO: suspicious RCU usage. ] [ 32.662922] 4.4.174+ #4 Not tainted [ 32.666519] ------------------------------- [ 32.670837] net/ipv6/ip6_fib.c:1465 suspicious rcu_dereference_protected() usage! [ 32.678450] [ 32.678450] other info that might help us debug this: [ 32.678450] [ 32.686574] [ 32.686574] rcu_scheduler_active = 1, debug_locks = 0 [ 32.693250] 4 locks held by syz-executor734/2078: [ 32.698089] #0: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 [ 32.706565] #1: (fib6_gc_lock){+.....}, at: [] fib6_run_gc+0x18c/0x230 [ 32.715578] #2: (rcu_read_lock){......}, at: [] __fib6_clean_all+0x0/0x240 [ 32.724948] #3: (&tb->tb6_lock){++....}, at: [] __fib6_clean_all+0xe8/0x240 [ 32.734391] [ 32.734391] stack backtrace: [ 32.738889] CPU: 1 PID: 2078 Comm: syz-executor734 Not tainted 4.4.174+ #4 [ 32.745880] 0000000000000000 61f24f216b50eb0c ffff8800b6e37530 ffffffff81aad1a1 [ 32.753866] ffff8800b6ccc380 0000000000000000 0000000000000001 00000000000005b9 [ 32.761853] ffff8800b7c197c0 ffff8800b6e37560 ffffffff813ab7d6 ffff8800b6e37780 [ 32.769849] Call Trace: [ 32.772410] [] dump_stack+0xc1/0x120 [ 32.777748] [] lockdep_rcu_suspicious.cold+0x10a/0x149 [ 32.784646] [] fib6_del+0x7ea/0xae0 [ 32.789904] [] ? trace_hardirqs_on+0x10/0x10 [ 32.795946] [] fib6_clean_node+0x29c/0x500 [ 32.801805] [] ? fib6_del+0xae0/0xae0 [ 32.807227] [] ? __local_bh_enable_ip+0x6a/0xe0 [ 32.813648] [] ? fib6_flush_trees+0xc0/0xc0 [ 32.819607] [] fib6_walk_continue+0x3e0/0x630 [ 32.825727] [] ? fib6_flush_trees+0xc0/0xc0 [ 32.831688] [] fib6_walk+0x91/0xe0 [ 32.836859] [] fib6_clean_tree+0xe8/0x120 [ 32.842650] [] ? fib6_walk+0xe0/0xe0 [ 32.848071] [] ? check_preemption_disabled+0x3c/0x200 [ 32.854941] [] ? fib6_del+0xae0/0xae0 [ 32.860384] [] ? fib6_flush_trees+0xc0/0xc0 [ 32.866329] [] ? check_preemption_disabled+0x3c/0x200 [ 32.873140] [] __fib6_clean_all+0x100/0x240 [ 32.879084] [] ? fib6_clean_tree+0x120/0x120 [ 32.885113] [] ? fib6_flush_trees+0xc0/0xc0 [ 32.891060] [] fib6_run_gc+0xaf/0x230 [ 32.896483] [] ndisc_netdev_event+0x2b0/0x360 [ 32.902657] [] notifier_call_chain+0xb9/0x1e0 [ 32.908780] [] raw_notifier_call_chain+0x2e/0x40 [ 32.915159] [] call_netdevice_notifiers_info+0x56/0x70 [ 32.922065] [] dev_close_many+0x2f3/0x6a0 [ 32.927839] [] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 32.934563] [] ? __dev_close_many+0x270/0x270 [ 32.940790] [] rollback_registered_many+0x3a0/0x9a0 [ 32.947436] [] ? netdev_rx_handler_unregister+0x90/0x90 [ 32.954429] [] ? mark_held_locks+0xb1/0x100 [ 32.960379] [] rollback_registered+0xf2/0x1b0 [ 32.966559] [] ? rollback_registered_many+0x9a0/0x9a0 [ 32.973379] [] ? queue_delayed_work_on+0x7c/0xb0 [ 32.979757] [] ? linkwatch_schedule_work+0x103/0x130 [ 32.986482] [] unregister_netdevice_queue+0x1ae/0x230 [ 32.993336] [] __tun_detach+0x86b/0xa50 [ 32.998937] [] ? __tun_detach+0xa50/0xa50 [ 33.004716] [] tun_chr_close+0x46/0x60 [ 33.010230] [] __fput+0x246/0x710 [ 33.016180] [] ____fput+0x16/0x20 [ 33.021266] [] task_work_run+0x202/0x2b0 [ 33.026956] [] do_exit+0x8ea/0x2c60 [ 33.032210] [] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 33.038934] [] ? release_task+0x14a0/0x14a0 [ 33.044877] [] ? __do_page_fault+0x2b3/0x7f0 [ 33.051003] [] ?