[  OK  ] Started Getty on tty2.
[  OK  ] Reached target Login Prompts.
[  OK  ] Started OpenBSD Secure Shell server.
[  OK  ] Listening on Load/Save RF Kill Switch Status /dev/rfkill Watch.
[  OK  ] Reached target Multi-User System.
[  OK  ] Reached target Graphical Interface.
         Starting Update UTMP about System Runlevel Changes...
         Starting Load/Save RF Kill Switch Status...
[  OK  ] Started Update UTMP about System Runlevel Changes.
[  OK  ] Started Load/Save RF Kill Switch Status.

Debian GNU/Linux 9 syzkaller ttyS0

Warning: Permanently added '10.128.0.222' (ECDSA) to the list of known hosts.
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syzkaller login: [   30.295387] BTRFS: device fsid c60cf190-3c65-4298-abf6-b290b3ceb27d devid 0 transid 7 /dev/loop0
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[   30.570194] BTRFS: device fsid c60cf190-3c65-4298-abf6-b290b3ceb27d devid 1 transid 7 /dev/loop4
[   30.596311] BTRFS info (device loop4): disk space caching is enabled
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[   30.621601] BTRFS info (device loop4): has skinny extents
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[   30.696106] BTRFS error (device loop4): bad tree block start 0 30441472
[   30.706502] BTRFS info (device loop4): read error corrected: ino 0 off 30441472 (dev /dev/loop5 sector 75840)
[   30.717855] BTRFS info (device loop4): read error corrected: ino 0 off 30445568 (dev /dev/loop5 sector 75848)
[   30.728800] BTRFS info (device loop4): read error corrected: ino 0 off 30449664 (dev /dev/loop5 sector 75856)
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[   30.779381] BTRFS info (device loop4): read error corrected: ino 0 off 30453760 (dev /dev/loop5 sector 75864)
[   30.808476] BTRFS error (device loop4): bad tree block start 0 30490624
[   30.820580] BTRFS error (device loop4): bad tree block start 0 30490624
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[   30.832052] BTRFS warning (device loop4): failed to recover relocation: -5
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[   30.904110] BTRFS error (device loop4): open_ctree failed
[   30.915434] BTRFS info (device loop4): disk space caching is enabled
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[   30.955379] BTRFS info (device loop4): has skinny extents
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[   31.117147] BTRFS error (device loop4): bad tree block start 0 30490624
[   31.126390] BTRFS error (device loop4): bad tree block start 0 30490624
[   31.133905] BTRFS warning (device loop4): failed to recover relocation: -5
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[   31.203028] BTRFS error (device loop4): open_ctree failed
[   31.211744] BTRFS info (device loop4): disk space caching is enabled
[   31.219242] BTRFS info (device loop4): has skinny extents
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[   31.291882] BTRFS error (device loop4): bad tree block start 0 30490624
[   31.319161] BTRFS error (device loop4): bad tree block start 0 30490624
[   31.327253] BTRFS warning (device loop4): failed to recover relocation: -5
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[   31.372803] BTRFS error (device loop4): open_ctree failed
[   31.383622] BTRFS info (device loop4): disk space caching is enabled
[   31.390163] BTRFS info (device loop4): has skinny extents
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[   31.481302] BTRFS error (device loop4): bad tree block start 0 30490624
[   31.488827] BTRFS error (device loop4): bad tree block start 0 30490624
[   31.496705] BTRFS warning (device loop4): failed to recover relocation: -5
executing program
executing program
[   31.542711] BTRFS error (device loop4): open_ctree failed
[   31.550431] BTRFS info (device loop4): disk space caching is enabled
[   31.557253] BTRFS info (device loop4): has skinny extents
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[   31.667493] BTRFS error (device loop4): bad tree block start 0 30490624
[   31.680502] BTRFS warning (device loop4): failed to recover relocation: -5
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[   31.822943] ------------[ cut here ]------------
[   31.827821] WARNING: CPU: 0 PID: 8089 at fs/btrfs/volumes.c:936 __btrfs_close_devices+0x888/0xb20
[   31.836826] Kernel panic - not syncing: panic_on_warn set ...
[   31.836826] 
[   31.844205] CPU: 0 PID: 8089 Comm: syz-executor014 Not tainted 4.14.218-syzkaller #0
[   31.852084] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   31.861437] Call Trace:
[   31.864034]  dump_stack+0x1b2/0x281
[   31.867672]  panic+0x1f9/0x42d
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[   31.870869]  ? add_taint.cold+0x16/0x16
[   31.874847]  ? __btrfs_close_devices+0x888/0xb20
[   31.879608]  ? __btrfs_close_devices+0x888/0xb20
[   31.884366]  __warn.cold+0x20/0x44
[   31.887905]  ? ist_end_non_atomic+0x10/0x10
[   31.892228]  ? __btrfs_close_devices+0x888/0xb20
[   31.896984]  report_bug+0x208/0x250
[   31.900613]  do_error_trap+0x195/0x2d0
[   31.904504]  ? math_error+0x2d0/0x2d0
[   31.908330]  ? trace_hardirqs_on_caller+0x3a8/0x580
[   31.913348]  ? _raw_spin_unlock_irqrestore+0x66/0xe0
[   31.918451]  ? debug_object_active_state+0x236/0x330
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[   31.923558]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   31.928405]  invalid_op+0x1b/0x40
[   31.931859] RIP: 0010:__btrfs_close_devices+0x888/0xb20
[   31.937226] RSP: 0018:ffff888096fd7618 EFLAGS: 00010297
[   31.942584] RAX: ffff8880b31d8140 RBX: dffffc0000000000 RCX: ffff888096fd7688
[   31.950388] RDX: 0000000000000000 RSI: ffff8880b31d89f0 RDI: ffff8880a1fdc560
[   31.957667] RBP: ffff8880b6104040 R08: 0000000000000282 R09: 0000000000000000
[   31.964929] R10: 0000000000000000 R11: 0000000000000000 R12: dead000000000200
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[   31.972198] R13: dead000000000100 R14: ffff88808fea0340 R15: ffff8880b61040e0
[   31.979491]  ? __btrfs_close_devices+0x888/0xb20
[   31.984257]  ? btrfs_alloc_device+0x580/0x580
[   31.988761]  btrfs_close_devices+0x24/0x140
[   31.993086]  open_ctree+0x241/0x7400
[   31.996840]  ? close_ctree+0x840/0x840
[   32.000741]  ? dlm_unlock_lock_handler+0x8d0/0x8d0
[   32.005680]  btrfs_mount+0x1915/0x1fe0
[   32.009581]  ? btrfs_get_subvol_name_from_objectid+0x8c0/0x8c0
[   32.015566]  ? rcu_lockdep_current_cpu_online+0xed/0x140
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[   32.021048]  ? rcu_read_lock_sched_held+0x16c/0x1d0
[   32.026057]  ? __lockdep_init_map+0x100/0x560
[   32.030543]  ? __lockdep_init_map+0x100/0x560
[   32.035047]  mount_fs+0x92/0x2a0
[   32.038415]  vfs_kern_mount.part.0+0x5b/0x470
[   32.042953]  vfs_kern_mount+0x3c/0x60
[   32.046748]  btrfs_mount+0x42a/0x1fe0
[   32.050585]  ? lock_downgrade+0x740/0x740
[   32.054727]  ? _find_next_bit+0xdb/0x100
[   32.058790]  ? btrfs_get_subvol_name_from_objectid+0x8c0/0x8c0
[   32.064770]  ? rcu_lockdep_current_cpu_online+0xed/0x140
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[   32.070222]  ? rcu_read_lock_sched_held+0x16c/0x1d0
[   32.075233]  ? __lockdep_init_map+0x100/0x560
[   32.079729]  ? __lockdep_init_map+0x100/0x560
[   32.084246]  mount_fs+0x92/0x2a0
[   32.087619]  vfs_kern_mount.part.0+0x5b/0x470
[   32.092123]  do_mount+0xe53/0x2a00
[   32.095673]  ? copy_mount_string+0x40/0x40
[   32.099909]  ? rcu_read_lock_sched_held+0x16c/0x1d0
[   32.104923]  ? copy_mnt_ns+0xa30/0xa30
[   32.108811]  ? copy_mount_options+0x1fa/0x2f0
[   32.113301]  ? copy_mnt_ns+0xa30/0xa30
[   32.117191]  SyS_mount+0xa8/0x120
[   32.120641]  ? copy_mnt_ns+0xa30/0xa30
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[   32.124536]  do_syscall_64+0x1d5/0x640
[   32.128427]  entry_SYSCALL_64_after_hwframe+0x46/0xbb
[   32.133613] RIP: 0033:0x44790a
[   32.136799] RSP: 002b:00007ffe069674f8 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
[   32.144506] RAX: ffffffffffffffda RBX: 00007ffe06967590 RCX: 000000000044790a
[   32.151775] RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffe06967550
[   32.159147] RBP: 00007ffe06967550 R08: 00007ffe06967590 R09: 0000000000000000
[   32.166407] R10: 0000000000000000 R11: 0000000000000282 R12: 0000000000000059
[   32.173679] R13: 0000000000000004 R14: 0000000000000003 R15: 0000000020000100
[   32.181890] Kernel Offset: disabled
[   32.185562] Rebooting in 86400 seconds..