[ 67.700733][ T27] audit: type=1800 audit(1576844630.369:25): pid=9123 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 67.727548][ T27] audit: type=1800 audit(1576844630.369:26): pid=9123 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 67.775583][ T27] audit: type=1800 audit(1576844630.379:27): pid=9123 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. [ 68.194323][ T9190] sshd (9190) used greatest stack depth: 21864 bytes left [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.182' (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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 94.248193][ T9727] ------------[ cut here ]------------ [ 94.253805][ T9727] WARNING: CPU: 1 PID: 9727 at lib/percpu-refcount.c:111 percpu_ref_exit+0xab/0xd0 [ 94.263082][ T9727] Kernel panic - not syncing: panic_on_warn set ... [ 94.270460][ T9727] CPU: 1 PID: 9727 Comm: syz-executor571 Not tainted 5.5.0-rc2-next-20191220-syzkaller #0 [ 94.280473][ T9727] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 94.290558][ T9727] Call Trace: [ 94.293856][ T9727] dump_stack+0x197/0x210 [ 94.298208][ T9727] ? percpu_ref_exit+0x10/0xd0 [ 94.302997][ T9727] panic+0x2e3/0x75c [ 94.306893][ T9727] ? add_taint.cold+0x16/0x16 [ 94.311558][ T9727] ? printk+0xba/0xed [ 94.315526][ T9727] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 94.320980][ T9727] ? __warn.cold+0x14/0x3e [ 94.325386][ T9727] ? __warn+0xd9/0x1cf [ 94.329447][ T9727] ? percpu_ref_exit+0xab/0xd0 [ 94.334317][ T9727] __warn.cold+0x2f/0x3e [ 94.338551][ T9727] ? report_bug.cold+0x63/0xb2 [ 94.343302][ T9727] ? percpu_ref_exit+0xab/0xd0 [ 94.348112][ T9727] report_bug+0x289/0x300 [ 94.352434][ T9727] do_error_trap+0x11b/0x200 [ 94.357119][ T9727] do_invalid_op+0x37/0x50 [ 94.361523][ T9727] ? percpu_ref_exit+0xab/0xd0 [ 94.366281][ T9727] invalid_op+0x23/0x30 [ 94.371014][ T9727] RIP: 0010:percpu_ref_exit+0xab/0xd0 [ 94.376378][ T9727] 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 [ 94.395971][ T9727] RSP: 0018:ffffc90003bf7968 EFLAGS: 00010293 [ 94.402037][ T9727] RAX: ffff8880a700e500 RBX: ffff8880990cde10 RCX: ffffffff83901432 [ 94.410524][ T9727] RDX: 0000000000000000 RSI: ffffffff8390149b RDI: ffff8880990cde28 [ 94.418489][ T9727] RBP: ffffc90003bf7980 R08: ffff8880a700e500 R09: 0000000000000000 [ 94.426463][ T9727] R10: 0000000000000000 R11: 0000000000000000 R12: 0000607f514357c0 [ 94.434428][ T9727] R13: ffff8880990cde18 R14: ffff8880973e3000 R15: ffff8880973e3228 [ 94.442409][ T9727] ? percpu_ref_exit+0x42/0xd0 [ 94.447293][ T9727] ? percpu_ref_exit+0xab/0xd0 [ 94.452311][ T9727] ? percpu_ref_exit+0xab/0xd0 [ 94.457061][ T9727] io_sqe_files_unregister+0x7d/0x2f0 [ 94.462515][ T9727] ? __mmdrop+0x239/0x320 [ 94.466832][ T9727] io_ring_ctx_wait_and_kill+0x430/0x9a0 [ 94.472446][ T9727] ? __sanitizer_cov_trace_const_cmp2+0x11/0x20 [ 94.478682][ T9727] io_uring_release+0x42/0x50 [ 94.483340][ T9727] __fput+0x2ff/0x890 [ 94.487306][ T9727] ? io_ring_ctx_wait_and_kill+0x9a0/0x9a0 [ 94.493125][ T9727] ____fput+0x16/0x20 [ 94.497106][ T9727] task_work_run+0x145/0x1c0 [ 94.501687][ T9727] do_exit+0x909/0x2f20 [ 94.505833][ T9727] ? get_signal+0x2c1/0x24f0 [ 94.510412][ T9727] ? mm_update_next_owner+0x7c0/0x7c0 [ 94.515818][ T9727] ? lock_downgrade+0x920/0x920 [ 94.520656][ T9727] ? _raw_spin_unlock_irq+0x23/0x80 [ 94.525930][ T9727] ? get_signal+0x392/0x24f0 [ 94.530516][ T9727] ? _raw_spin_unlock_irq+0x23/0x80 [ 94.535709][ T9727] do_group_exit+0x135/0x360 [ 94.540503][ T9727] get_signal+0x47c/0x24f0 [ 94.544951][ T9727] ? __x64_sys_io_uring_register+0x1b0/0x570 [ 94.550930][ T9727] ? __io_uring_register+0x118/0x2790 [ 94.556304][ T9727] do_signal+0x87/0x1700 [ 94.560536][ T9727] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 94.566763][ T9727] ? debug_smp_processor_id+0x33/0x18a [ 94.572224][ T9727] ? rcu_lockdep_current_cpu_online+0xe3/0x130 [ 94.579766][ T9727] ? setup_sigcontext+0x7d0/0x7d0 [ 94.584804][ T9727] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 94.590380][ T9727] ? exit_to_usermode_loop+0x43/0x380 [ 94.600017][ T9727] ? do_syscall_64+0x676/0x790 [ 94.604778][ T9727] ? exit_to_usermode_loop+0x43/0x380 [ 94.610249][ T9727] ? lockdep_hardirqs_on+0x421/0x5e0 [ 94.615606][ T9727] ? trace_hardirqs_on+0x67/0x240 [ 94.620618][ T9727] exit_to_usermode_loop+0x286/0x380 [ 94.625922][ T9727] do_syscall_64+0x676/0x790 [ 94.630535][ T9727] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 94.636419][ T9727] RIP: 0033:0x4468f9 [ 94.640315][ T9727] Code: e8 0c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 5b 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 94.659910][ T9727] RSP: 002b:00007fb197749db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca [ 94.668315][ T9727] RAX: fffffffffffffe00 RBX: 00000000006dbc48 RCX: 00000000004468f9 [ 94.676280][ T9727] RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00000000006dbc48 [ 94.684247][ T9727] RBP: 00000000006dbc40 R08: 0000000000000000 R09: 0000000000000000 [ 94.692292][ T9727] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc4c [ 94.700259][ T9727] R13: 00007ffc42ed8b0f R14: 00007fb19774a9c0 R15: 0000000000000001 [ 94.709748][ T9727] Kernel Offset: disabled [ 94.714165][ T9727] Rebooting in 86400 seconds..