[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 66.157025][ T27] audit: type=1800 audit(1577615986.703:25): pid=9175 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 66.187623][ T27] audit: type=1800 audit(1577615986.703:26): pid=9175 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 66.247112][ T27] audit: type=1800 audit(1577615986.703:27): pid=9175 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 '10.128.0.12' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 76.618747][ T9341] ------------[ cut here ]------------ [ 76.624274][ T9341] WARNING: CPU: 1 PID: 9341 at lib/percpu-refcount.c:111 percpu_ref_exit+0xab/0xd0 [ 76.633550][ T9341] Kernel panic - not syncing: panic_on_warn set ... [ 76.640149][ T9341] CPU: 1 PID: 9341 Comm: syz-executor536 Not tainted 5.5.0-rc2-next-20191220-syzkaller #0 [ 76.650030][ T9341] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 76.660092][ T9341] Call Trace: [ 76.663406][ T9341] dump_stack+0x197/0x210 [ 76.668085][ T9341] ? percpu_ref_exit+0x10/0xd0 [ 76.672829][ T9341] panic+0x2e3/0x75c [ 76.676793][ T9341] ? add_taint.cold+0x16/0x16 [ 76.681470][ T9341] ? printk+0xba/0xed [ 76.685446][ T9341] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 76.690885][ T9341] ? __warn.cold+0x14/0x3e [ 76.695284][ T9341] ? __warn+0xd9/0x1cf [ 76.699335][ T9341] ? percpu_ref_exit+0xab/0xd0 [ 76.704088][ T9341] __warn.cold+0x2f/0x3e [ 76.708321][ T9341] ? report_bug.cold+0x63/0xb2 [ 76.713156][ T9341] ? percpu_ref_exit+0xab/0xd0 [ 76.717921][ T9341] report_bug+0x289/0x300 [ 76.722249][ T9341] do_error_trap+0x11b/0x200 [ 76.726837][ T9341] do_invalid_op+0x37/0x50 [ 76.731259][ T9341] ? percpu_ref_exit+0xab/0xd0 [ 76.736025][ T9341] invalid_op+0x23/0x30 [ 76.740177][ T9341] RIP: 0010:percpu_ref_exit+0xab/0xd0 [ 76.745609][ T9341] Code: 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 75 1d 48 c7 43 08 03 00 00 00 e8 01 41 e5 fd 5b 41 5c 41 5d 5d c3 e8 f5 40 e5 fd <0f> 0b eb bf 4c 89 ef e8 29 2c 23 fe eb d9 e8 82 2b 23 fe eb a7 4c [ 76.765197][ T9341] RSP: 0018:ffffc90002027bc0 EFLAGS: 00010293 [ 76.771272][ T9341] RAX: ffff8880a9774280 RBX: ffff88809e4e7410 RCX: ffffffff83901432 [ 76.779237][ T9341] RDX: 0000000000000000 RSI: ffffffff8390149b RDI: ffff88809e4e7428 [ 76.788153][ T9341] RBP: ffffc90002027bd8 R08: ffff8880a9774280 R09: 0000000000000000 [ 76.796115][ T9341] R10: 0000000000000000 R11: 0000000000000000 R12: 0000607f51434ff0 [ 76.804164][ T9341] R13: ffff88809e4e7418 R14: ffff8880a4b92000 R15: ffff8880a4b92228 [ 76.812133][ T9341] ? percpu_ref_exit+0x42/0xd0 [ 76.816891][ T9341] ? percpu_ref_exit+0xab/0xd0 [ 76.821641][ T9341] io_sqe_files_unregister+0x7d/0x2f0 [ 76.827013][ T9341] ? __mmdrop+0x239/0x320 [ 76.831330][ T9341] io_ring_ctx_wait_and_kill+0x430/0x9a0 [ 76.836950][ T9341] ? __sanitizer_cov_trace_const_cmp2+0x11/0x20 [ 76.843190][ T9341] io_uring_release+0x42/0x50 [ 76.847849][ T9341] __fput+0x2ff/0x890 [ 76.851817][ T9341] ? io_ring_ctx_wait_and_kill+0x9a0/0x9a0 [ 76.857609][ T9341] ____fput+0x16/0x20 [ 76.861576][ T9341] task_work_run+0x145/0x1c0 [ 76.866165][ T9341] do_exit+0x909/0x2f20 [ 76.870306][ T9341] ? mm_update_next_owner+0x7c0/0x7c0 [ 76.875659][ T9341] ? down_read_non_owner+0x490/0x490 [ 76.881624][ T9341] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 76.887852][ T9341] ? handle_mm_fault+0x4ab/0xa50 [ 76.892787][ T9341] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 76.898235][ T9341] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 76.903677][ T9341] do_group_exit+0x135/0x360 [ 76.908252][ T9341] __x64_sys_exit_group+0x44/0x50 [ 76.913255][ T9341] do_syscall_64+0xfa/0x790 [ 76.917757][ T9341] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 76.923637][ T9341] RIP: 0033:0x440008 [ 76.927538][ T9341] Code: 00 00 be 3c 00 00 00 eb 19 66 0f 1f 84 00 00 00 00 00 48 89 d7 89 f0 0f 05 48 3d 00 f0 ff ff 77 21 f4 48 89 d7 44 89 c0 0f 05 <48> 3d 00 f0 ff ff 76 e0 f7 d8 64 41 89 01 eb d8 0f 1f 84 00 00 00 [ 76.947155][ T9341] RSP: 002b:00007fff77bf2838 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 76.955543][ T9341] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440008 [ 76.963544][ T9341] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 76.971510][ T9341] RBP: 00000000004bf830 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 76.979636][ T9341] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 76.987588][ T9341] R13: 00000000006d1180 R14: 0000000000000000 R15: 0000000000000000 [ 76.997039][ T9341] Kernel Offset: disabled [ 77.001421][ T9341] Rebooting in 86400 seconds..