[ 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. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.10.13' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 79.785170] audit: type=1400 audit(1601361785.656:8): avc: denied { execmem } for pid=6361 comm="syz-executor298" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1 [ 79.797244] ip_tables: iptables: counters copy to user failed while replacing table [ 79.816538] ip_tables: iptables: counters copy to user failed while replacing table [ 79.825474] ip_tables: iptables: counters copy to user failed while replacing table [ 79.834060] ip_tables: iptables: counters copy to user failed while replacing table [ 79.842940] ip_tables: iptables: counters copy to user failed while replacing table [ 79.853198] ip_tables: iptables: counters copy to user failed while replacing table [ 79.861170] ip_tables: iptables: counters copy to user failed while replacing table [ 79.869064] ip_tables: iptables: counters copy to user failed while replacing table [ 79.877284] ip_tables: iptables: counters copy to user failed while replacing table [ 79.885964] ip_tables: iptables: counters copy to user failed while replacing table [ 79.894794] [ 79.896571] ============================= [ 79.900710] WARNING: suspicious RCU usage [ 79.904894] 4.14.198-syzkaller #0 Not tainted [ 79.909403] ----------------------------- [ 79.913588] net/netfilter/nf_queue.c:227 suspicious rcu_dereference_check() usage! [ 79.922212] [ 79.922212] other info that might help us debug this: [ 79.922212] [ 79.932404] [ 79.932404] rcu_scheduler_active = 2, debug_locks = 1 [ 79.939092] 2 locks held by ksoftirqd/1/17: [ 79.943457] #0: (rcu_callback){....}, at: [] rcu_process_callbacks+0x84e/0x1180 [ 79.952717] #1: (&(&inst->lock)->rlock){+.-.}, at: [] nfqnl_flush+0x2f/0x2a0 [ 79.961925] [ 79.961925] stack backtrace: [ 79.966420] CPU: 1 PID: 17 Comm: ksoftirqd/1 Not tainted 4.14.198-syzkaller #0 [ 79.973772] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 79.983141] Call Trace: [ 79.985760] dump_stack+0x1b2/0x283 [ 79.989394] nf_reinject+0x56e/0x700 [ 79.993110] nfqnl_flush+0x1ab/0x2a0 [ 79.996825] instance_destroy_rcu+0x19/0x30 [ 80.001180] ? nfqnl_rcv_nl_event+0x290/0x290 [ 80.005671] rcu_process_callbacks+0x780/0x1180 [ 80.010344] ? note_gp_changes+0x2f0/0x2f0 [ 80.014594] ? sched_clock+0x2a/0x40 [ 80.018320] ? rcu_lockdep_current_cpu_online+0xed/0x140 [ 80.023770] __do_softirq+0x254/0xa1d [ 80.027575] ? __local_bh_enable_ip+0x170/0x170 [ 80.032242] run_ksoftirqd+0x50/0x1a0 [ 80.036045] smpboot_thread_fn+0x5c1/0x920 [ 80.040278] ? sort_range+0x30/0x30 [ 80.043904] ? sort_range+0x30/0x30 [ 80.047529] kthread+0x30d/0x420 [ 80.050894] ? kthread_create_on_node+0xd0/0xd0 [ 80.055561] ret_from_fork+0x24/0x30 [ 84.802174] net_ratelimit: 3416 callbacks suppressed [ 84.802178] ip_tables: iptables: counters copy to user failed while replacing table [ 84.817090] ip_tables: iptables: counters copy to user failed while replacing table [ 84.826931] ip_tables: iptables: counters copy to user failed while replacing table [ 84.835910] ip_tables: iptables: counters copy to user failed while replacing table [ 84.844353] ip_tables: iptables: counters copy to user failed while replacing table [ 84.853665] ip_tables: iptables: counters copy to user failed while replacing table [ 84.861830] ip_tables: iptables: counters copy to user failed while replacing table [ 84.870081] ip_tables: iptables: counters copy to user failed while replacing table [ 84.879035] ip_tables: iptables: counters copy to user failed while replacing table [ 84.888215] ip_tables: iptables: counters copy to user failed while replacing table [ 89.812070] net_ratelimit: 3527 callbacks suppressed [ 89.812074] ip_tables: iptables: counters copy to user failed while replacing table [ 89.826684] ip_tables: iptables: counters copy to user failed while replacing table [ 89.836548] ip_tables: iptables: counters copy to user failed while replacing table [ 89.845071] ip_tables: iptables: counters copy to user failed while replacing table [ 89.854573] ip_tables: iptables: counters copy to user failed while replacing table