[   11.247808] btrfs: relocating block group 7428158521344 flags 17
[  157.464975] btrfs: found 52 extents
[  159.568632] ------------[ cut here ]------------
[  159.569591] Kernel BUG at ffffffffa014a167 [verbose debug info unavailable]
[  159.570424] invalid opcode: 0000 [#1] SMP 
[  159.571109] Modules linked in: dm_crypt(F) kvm_intel(F) kvm(F) microcode(F) psmouse(F) serio_raw(F) virtio_balloon(F) i2c_piix4 lp(F) parport(F) mac_hid btrfs(F) xor(F) zlib_deflate(F) raid6_pq(F) libcrc32c(F) cirrus syscopyarea(F) sysfillrect(F) sysimgblt(F) ttm drm_kms_helper drm floppy(F)
[  159.572504] CPU: 0 PID: 609 Comm: btrfs-balance Tainted: GF            3.11.0-12-generic #19-Ubuntu
[  159.572504] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[  159.572504] task: ffff8800b3455dc0 ti: ffff8800b574e000 task.ti: ffff8800b574e000
[  159.572504] RIP: 0010:[<ffffffffa014a167>]  [<ffffffffa014a167>] build_backref_tree+0x277/0x11d0 [btrfs]
[  159.572504] RSP: 0018:ffff8800b574fa90  EFLAGS: 00010246
[  159.572504] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88004c7fbed0
[  159.572504] RDX: ffff8800b574fb00 RSI: ffff8800b574fb00 RDI: ffff88004c7fbec0
[  159.572504] RBP: ffff8800b574fb70 R08: ffff880048ed0100 R09: ffff880048ed0b00
[  159.572504] R10: 0000000000000001 R11: 0000000000000000 R12: ffff88004c7fbed0
[  159.572504] R13: ffff8800b6002240 R14: ffff8800b2973000 R15: ffff880048ed0480
[  159.572504] FS:  0000000000000000(0000) GS:ffff8800bb200000(0000) knlGS:0000000000000000
[  159.572504] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[  159.572504] CR2: 00000000010e7160 CR3: 000000004f47e000 CR4: 00000000000006f0
[  159.572504] Stack:
[  159.572504]  ffff8800b2973588 ffff880048ed0b00 ffff88004c7fb6a0 ffff880048ed0100
[  159.572504]  ffff880048ed0100 ffff8800b5a39800 ffff8800b6002240 ffff880048ed0140
[  159.572504]  ffff8800b6002480 ffff8800b2973120 ffff880048ed0b00 ffff8800b2973020
[  159.572504] Call Trace:
[  159.572504]  [<ffffffffa014b478>] relocate_tree_blocks+0x1d8/0x630 [btrfs]
[  159.572504]  [<ffffffffa014c108>] ? add_data_references+0x248/0x280 [btrfs]
[  159.572504]  [<ffffffffa014cd00>] relocate_block_group+0x280/0x690 [btrfs]
[  159.572504]  [<ffffffffa014d2af>] btrfs_relocate_block_group+0x19f/0x2e0 [btrfs]
[  159.572504]  [<ffffffffa012477f>] btrfs_relocate_chunk.isra.30+0x6f/0x730 [btrfs]
[  159.572504]  [<ffffffffa00dab89>] ? btrfs_set_path_blocking+0x39/0x80 [btrfs]
[  159.572504]  [<ffffffffa00df940>] ? btrfs_search_slot+0x380/0x940 [btrfs]
[  159.572504]  [<ffffffffa011b289>] ? release_extent_buffer+0x69/0xd0 [btrfs]
[  159.572504]  [<ffffffffa0120c8f>] ? free_extent_buffer+0x4f/0xa0 [btrfs]
[  159.572504]  [<ffffffffa0128ecd>] __btrfs_balance+0x43d/0x800 [btrfs]
[  159.572504]  [<ffffffffa012964b>] btrfs_balance+0x3bb/0x670 [btrfs]
[  159.572504]  [<ffffffffa0129970>] balance_kthread+0x70/0x80 [btrfs]
[  159.572504]  [<ffffffffa0129900>] ? btrfs_balance+0x670/0x670 [btrfs]
[  159.572504]  [<ffffffff810847b0>] kthread+0xc0/0xd0
[  159.572504]  [<ffffffff810846f0>] ? kthread_create_on_node+0x120/0x120
[  159.572504]  [<ffffffff816f516c>] ret_from_fork+0x7c/0xb0
[  159.572504]  [<ffffffff810846f0>] ? kthread_create_on_node+0x120/0x120
[  159.572504] Code: f6 43 71 10 0f 85 18 0f 00 00 48 8d 43 40 48 89 c6 48 89 85 58 ff ff ff 48 8b 43 40 48 39 c6 74 0c 48 3b 43 48 0f 84 f5 08 00 00 <0f> 0b 48 c7 85 78 ff ff ff 00 00 00 00 0f 1f 40 00 e8 93 07 5a 
[  159.572504] RIP  [<ffffffffa014a167>] build_backref_tree+0x277/0x11d0 [btrfs]
[  159.572504]  RSP <ffff8800b574fa90>
[  159.616982] ---[ end trace 3f27f3e0ff311a02 ]---
[645622.149145] SGI XFS with ACLs, security attributes, realtime, large block/inode numbers, no debug enabled
[645622.195799] JFS: nTxBlock = 8192, nTxLock = 65536
[645622.252611] NTFS driver 2.1.30 [Flags: R/O MODULE].
[645622.362604] QNX4 filesystem 0.2.3 registered.