[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 64.672875][ T28] audit: type=1800 audit(1579867869.644:25): pid=8743 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 64.692080][ T28] audit: type=1800 audit(1579867869.644:26): pid=8743 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 64.713603][ T28] audit: type=1800 audit(1579867869.674:27): pid=8743 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.208' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 379.040674][ C1] rcu: INFO: rcu_preempt self-detected stall on CPU [ 379.049967][ C1] rcu: 1-....: (10500 ticks this GP) idle=b52/1/0x4000000000000002 softirq=13996/13996 fqs=5248 [ 379.062329][ C1] (t=10502 jiffies g=7337 q=2939) [ 379.067645][ C1] NMI backtrace for cpu 1 [ 379.072148][ C1] CPU: 1 PID: 8895 Comm: syz-executor098 Not tainted 5.5.0-rc7-syzkaller #0 [ 379.081071][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 379.091669][ C1] Call Trace: [ 379.095005][ C1] [ 379.098154][ C1] dump_stack+0x1fb/0x318 [ 379.102590][ C1] nmi_cpu_backtrace+0xaa/0x190 [ 379.107657][ C1] ? nmi_trigger_cpumask_backtrace+0x168/0x290 [ 379.114277][ C1] ? arch_trigger_cpumask_backtrace+0x20/0x20 [ 379.120461][ C1] nmi_trigger_cpumask_backtrace+0x16f/0x290 [ 379.126665][ C1] arch_trigger_cpumask_backtrace+0x10/0x20 [ 379.134504][ C1] rcu_dump_cpu_stacks+0x15a/0x220 [ 379.139975][ C1] rcu_sched_clock_irq+0x1521/0x1ab0 [ 379.145918][ C1] ? trace_hardirqs_off+0x74/0x80 [ 379.151206][ C1] update_process_times+0x12d/0x180 [ 379.157160][ C1] tick_sched_timer+0x263/0x420 [ 379.162460][ C1] ? tick_setup_sched_timer+0x3e0/0x3e0 [ 379.168181][ C1] __hrtimer_run_queues+0x3f3/0x840 [ 379.173910][ C1] hrtimer_interrupt+0x37c/0xda0 [ 379.180239][ C1] ? debug_smp_processor_id+0x9/0x20 [ 379.185785][ C1] smp_apic_timer_interrupt+0x109/0x280 [ 379.191444][ C1] apic_timer_interrupt+0xf/0x20 [ 379.196571][ C1] [ 379.199888][ C1] RIP: 0010:lock_is_held_type+0x25c/0x2b0 [ 379.206125][ C1] Code: 28 91 0a 89 48 c1 e8 03 42 80 3c 30 00 74 0c 48 c7 c7 28 91 0a 89 e8 c3 2b 57 00 48 83 3d 63 fe ae 07 00 74 56 4c 89 e7 57 9d <0f> 1f 44 00 00 89 d8 48 83 c4 28 5b 41 5c 41 5d 41 5e 41 5f 5d c3 [ 379.227314][ C1] RSP: 0018:ffffc90002077120 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 379.235827][ C1] RAX: 1ffffffff1215225 RBX: 0000000000000001 RCX: 0000000000000000 [ 379.243904][ C1] RDX: 00000000ffffffff RSI: ffff88809fa54638 RDI: 0000000000000282 [ 379.251894][ C1] RBP: ffffc90002077170 R08: ffffffff86a708bc R09: ffffffff83b538c7 [ 379.260722][ C1] R10: ffff8880a861c1c0 R11: 0000000000000004 R12: 0000000000000282 [ 379.269855][ C1] R13: ffff8880a861ca54 R14: dffffc0000000000 R15: 1ffff110150c394a [ 379.278508][ C1] ? __nla_validate_parse+0xc67/0x1ed0 [ 379.284522][ C1] ? hash_ip4_del+0x7c/0xb50 [ 379.289157][ C1] hash_ip4_del+0xa5/0xb50 [ 379.293777][ C1] ? __nla_validate_parse+0xc67/0x1ed0 [ 379.299492][ C1] ? hash_ip4_uadt+0x5a2/0x810 [ 379.304854][ C1] hash_ip4_uadt+0x589/0x810 [ 379.309806][ C1] ? hash_ip4_add+0x1500/0x1500 [ 379.315078][ C1] call_ad+0x10a/0x5b0 [ 379.319412][ C1] ? __nla_parse+0x41/0x50 [ 379.323844][ C1] ip_set_ad+0x6a9/0x860 [ 379.328129][ C1] ip_set_udel+0x3a/0x50 [ 379.332568][ C1] ? ip_set_uadd+0x50/0x50 [ 379.337016][ C1] nfnetlink_rcv_msg+0x9ae/0xcd0 [ 379.342220][ C1] ? cap_capable+0x25b/0x290 [ 379.347008][ C1] ? cap_capable+0x25b/0x290 [ 379.351613][ C1] netlink_rcv_skb+0x19e/0x3e0 [ 379.356876][ C1] ? nfnetlink_bind+0x250/0x250 [ 379.361831][ C1] nfnetlink_rcv+0x1e0/0x1e50 [ 379.367042][ C1] ? rcu_lock_release+0x9/0x30 [ 379.372028][ C1] ? rcu_lock_release+0x21/0x30 [ 379.378053][ C1] ? netlink_deliver_tap+0x142/0x880 [ 379.383642][ C1] netlink_unicast+0x767/0x920 [ 379.388569][ C1] netlink_sendmsg+0xa2c/0xd50 [ 379.393587][ C1] ? netlink_getsockopt+0x9f0/0x9f0 [ 379.398923][ C1] ____sys_sendmsg+0x4f7/0x7f0 [ 379.403988][ C1] __sys_sendmsg+0x1ed/0x290 [ 379.409382][ C1] ? check_preemption_disabled+0xb4/0x260 [ 379.415225][ C1] ? debug_smp_processor_id+0x9/0x20 [ 379.421652][ C1] ? debug_smp_processor_id+0x1c/0x20 [ 379.427984][ C1] ? fpregs_assert_state_consistent+0xb6/0xe0 [ 379.435238][ C1] ? prepare_exit_to_usermode+0x221/0x5b0 [ 379.441221][ C1] ? trace_irq_disable_rcuidle+0x23/0x1e0 [ 379.447165][ C1] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 379.453658][ C1] ? trace_irq_disable_rcuidle+0x23/0x1e0 [ 379.460977][ C1] ? do_syscall_64+0x1d/0x1c0 [ 379.466154][ C1] __x64_sys_sendmsg+0x7f/0x90 [ 379.471022][ C1] do_syscall_64+0xf7/0x1c0 [ 379.475873][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 379.481779][ C1] RIP: 0033:0x440509 [ 379.485794][ C1] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 379.506953][ C1] RSP: 002b:00007ffd23b04ed8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 379.516138][ C1] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440509 [ 379.524922][ C1] RDX: 0000000000000040 RSI: 0000000020000080 RDI: 0000000000000004 [ 379.535590][ C1] RBP: 00000000006ca018 R08: 0000000000000018 R09: 00000000004002c8 [ 379.545330][ C1] R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000401d90 [ 379.553537][ C1] R13: 0000000000401e20 R14: 0000000000000000 R15: 0000000000000000