[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 55.266249][ T27] audit: type=1800 audit(1571804495.634:25): pid=8435 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 55.310585][ T27] audit: type=1800 audit(1571804495.634:26): pid=8435 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 55.348670][ T27] audit: type=1800 audit(1571804495.644:27): pid=8435 uid=0 auid=4294967295 ses=4294967295 subj==unconfined 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 '10.128.0.177' (ECDSA) to the list of known hosts. syzkaller login: [ 63.174068][ T1081] ------------[ cut here ]------------ [ 63.179570][ T1081] WARNING: CPU: 1 PID: 1081 at mm/khugepaged.c:1643 collapse_file+0x1f9d/0x4170 [ 63.188568][ T1081] Kernel panic - not syncing: panic_on_warn set ... [ 63.195178][ T1081] CPU: 1 PID: 1081 Comm: khugepaged Not tainted 5.4.0-rc4-next-20191022 #0 [ 63.203772][ T1081] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 63.213801][ T1081] Call Trace: [ 63.217084][ T1081] dump_stack+0x172/0x1f0 [ 63.221391][ T1081] ? collapse_file+0x1ef0/0x4170 [ 63.226302][ T1081] panic+0x2e3/0x75c [ 63.230201][ T1081] ? add_taint.cold+0x16/0x16 [ 63.234901][ T1081] ? printk+0xba/0xed [ 63.238869][ T1081] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 63.244304][ T1081] ? __warn.cold+0x14/0x35 [ 63.248694][ T1081] ? __warn+0xd9/0x1d0 [ 63.252740][ T1081] ? collapse_file+0x1f9d/0x4170 [ 63.257652][ T1081] __warn.cold+0x2f/0x35 [ 63.261869][ T1081] ? report_bug.cold+0x63/0xb2 [ 63.266611][ T1081] ? collapse_file+0x1f9d/0x4170 [ 63.271529][ T1081] report_bug+0x289/0x300 [ 63.275837][ T1081] do_error_trap+0x11b/0x200 [ 63.280404][ T1081] do_invalid_op+0x37/0x50 [ 63.284816][ T1081] ? collapse_file+0x1f9d/0x4170 [ 63.289745][ T1081] invalid_op+0x23/0x30 [ 63.293882][ T1081] RIP: 0010:collapse_file+0x1f9d/0x4170 [ 63.299447][ T1081] Code: a1 c0 ff 31 c9 ba 01 00 00 00 4c 89 fe 48 8b bd c0 fe ff ff e8 e4 e9 ec ff e9 b4 fd ff ff 4c 8b bd 88 fe ff ff e8 93 a1 c0 ff <0f> 0b 4c 8b a3 50 ff ff ff c7 85 80 fe ff ff 00 00 00 00 e9 05 f6 [ 63.319030][ T1081] RSP: 0018:ffff8880a7f37ad0 EFLAGS: 00010293 [ 63.325071][ T1081] RAX: ffff8880a7f24480 RBX: ffff8880a7f37c88 RCX: ffffffff81b2b688 [ 63.333033][ T1081] RDX: 0000000000000000 RSI: ffffffff81b2b9ad RDI: 0000000000000001 [ 63.340990][ T1081] RBP: ffff8880a7f37cb0 R08: ffff8880a7f24480 R09: fffff94000475651 [ 63.348937][ T1081] R10: fffff94000475650 R11: ffffea00023ab287 R12: 0000000000000001 [ 63.356883][ T1081] R13: ffffea0000278848 R14: 0000000000000000 R15: ffffea0002338000 [ 63.364856][ T1081] ? collapse_file+0x1c78/0x4170 [ 63.369771][ T1081] ? collapse_file+0x1f9d/0x4170 [ 63.374688][ T1081] ? rcu_lockdep_current_cpu_online+0xe3/0x130 [ 63.380824][ T1081] ? khugepaged+0x21d0/0x4360 [ 63.385480][ T1081] ? trace_event_raw_event_mm_collapse_huge_page_isolate+0x370/0x370 [ 63.393548][ T1081] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 63.399245][ T1081] ? khugepaged_find_target_node+0x142/0x180 [ 63.405202][ T1081] khugepaged+0x2da9/0x4360 [ 63.409683][ T1081] ? __kasan_check_read+0x11/0x20 [ 63.414685][ T1081] ? __lock_acquire+0x16f2/0x4a00 [ 63.419686][ T1081] ? _raw_spin_unlock_irq+0x23/0x80 [ 63.424859][ T1081] ? finish_task_switch+0x147/0x750 [ 63.430033][ T1081] ? _raw_spin_unlock_irq+0x23/0x80 [ 63.435211][ T1081] ? lockdep_hardirqs_on+0x421/0x5e0 [ 63.440526][ T1081] ? collapse_pte_mapped_thp+0xbe0/0xbe0 [ 63.446154][ T1081] ? lock_downgrade+0x920/0x920 [ 63.450985][ T1081] ? finish_wait+0x260/0x260 [ 63.455554][ T1081] ? lockdep_hardirqs_on+0x421/0x5e0 [ 63.460824][ T1081] ? trace_hardirqs_on+0x67/0x240 [ 63.465827][ T1081] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 63.472061][ T1081] ? __kthread_parkme+0x108/0x1c0 [ 63.477073][ T1081] ? __kasan_check_read+0x11/0x20 [ 63.482077][ T1081] kthread+0x361/0x430 [ 63.486125][ T1081] ? collapse_pte_mapped_thp+0xbe0/0xbe0 [ 63.491733][ T1081] ? kthread_mod_delayed_work+0x1f0/0x1f0 [ 63.497426][ T1081] ret_from_fork+0x24/0x30 [ 63.503151][ T1081] Kernel Offset: disabled [ 63.507546][ T1081] Rebooting in 86400 seconds..