Kernel trace triggered by this test:
[  385.822256] ------------[ cut here ]------------
[  385.822262] WARNING: CPU: 1 PID: 1487 at /build/linux-pWDSBu/linux-3.13.0/mm/page_alloc.c:2552 __alloc_pages_nodemask+0x455/0xb90()
[  385.822263] Modules linked in: ib_iser rdma_cm iw_cm ib_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi dm_crypt x86_pkg_temp_thermal coretemp kvm_intel kvm joydev lpc_ich shpchp mac_hid btrfs xor raid6_pq libcrc32c crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel igb aes_x86_64 hid_generic lrw i915_bdw dca gf128mul intel_ips glue_helper usbhid ptp ablk_helper drm_kms_helper cryptd ahci hid drm pps_core libahci i2c_algo_bit video
[  385.822286] CPU: 1 PID: 1487 Comm: btrfs Not tainted 3.13.0-164-generic #214-Ubuntu
[  385.822287] Hardware name: Intel Corporation S1200RP/S1200RP, BIOS S1200RP.86B.03.02.0003.070120151022 07/01/2015
[  385.822288]  0000000000000000 ffff8804551916d8 ffffffff8173c0c8 0000000000000000
[  385.822290]  0000000000000009 ffff880455191710 ffffffff8106db6d 0000000000124050
[  385.822292]  0000000000000000 0000000000104050 0000000000000000 0000000000000000
[  385.822294] Call Trace:
[  385.822298]  [<ffffffff8173c0c8>] dump_stack+0x64/0x80
[  385.822301]  [<ffffffff8106db6d>] warn_slowpath_common+0x7d/0xa0
[  385.822303]  [<ffffffff8106dc4a>] warn_slowpath_null+0x1a/0x20
[  385.822305]  [<ffffffff81161bd5>] __alloc_pages_nodemask+0x455/0xb90
[  385.822317]  [<ffffffffa02dfa4d>] ? generic_bin_search.constprop.35+0x8d/0x1a0 [btrfs]
[  385.822320]  [<ffffffff811a1e53>] alloc_pages_current+0xa3/0x160
[  385.822323]  [<ffffffff8115c92e>] __get_free_pages+0xe/0x50
[  385.822325]  [<ffffffff81179abe>] kmalloc_order_trace+0x2e/0xc0
[  385.822327]  [<ffffffff811afc3f>] __kmalloc_track_caller+0x23f/0x260
[  385.822336]  [<ffffffffa0363e67>] ? fs_path_ensure_buf+0x67/0x1c0 [btrfs]
[  385.822338]  [<ffffffff81173d7f>] krealloc+0x4f/0xa0
[  385.822345]  [<ffffffffa0363e67>] fs_path_ensure_buf+0x67/0x1c0 [btrfs]
[  385.822352]  [<ffffffffa0363ff3>] fs_path_prepare_for_add+0x33/0xa0 [btrfs]
[  385.822359]  [<ffffffffa0364ae0>] fs_path_add_path+0x20/0x50 [btrfs]
[  385.822365]  [<ffffffffa0364fdb>] get_cur_path+0x6b/0x140 [btrfs]
[  385.822371]  [<ffffffffa0365340>] send_utimes+0xd0/0x190 [btrfs]
[  385.822378]  [<ffffffffa03662ce>] finish_inode_if_needed+0x1fe/0x4e0 [btrfs]
[  385.822384]  [<ffffffffa0367e35>] changed_cb+0x55/0x9f0 [btrfs]
[  385.822392]  [<ffffffffa0324e5c>] ? read_extent_buffer+0xbc/0x110 [btrfs]
[  385.822399]  [<ffffffffa0319d89>] ? btrfs_get_token_32+0x59/0xe0 [btrfs]
[  385.822406]  [<ffffffffa03255f1>] ? memcmp_extent_buffer+0xc1/0x120 [btrfs]
[  385.822411]  [<ffffffffa02e4fb3>] btrfs_compare_trees+0x783/0x960 [btrfs]
[  385.822418]  [<ffffffffa0367de0>] ? process_extent+0x1180/0x1180 [btrfs]
[  385.822424]  [<ffffffffa0369078>] btrfs_ioctl_send+0x8a8/0xc90 [btrfs]
[  385.822432]  [<ffffffffa0337579>] btrfs_ioctl+0x1129/0x2770 [btrfs]
[  385.822434]  [<ffffffff810ad752>] ? enqueue_task_fair+0x422/0x6d0
[  385.822436]  [<ffffffff810a4cc5>] ? sched_clock_cpu+0xb5/0x100
[  385.822439]  [<ffffffff8109b8d0>] ? enqueue_task+0x40/0x70
[  385.822441]  [<ffffffff810a1ba0>] ? wake_up_new_task+0x110/0x1a0
[  385.822444]  [<ffffffff811dc653>] do_vfs_ioctl+0x2e3/0x4d0
[  385.822446]  [<ffffffff811dc8c1>] SyS_ioctl+0x81/0xa0
[  385.822448]  [<ffffffff8174d37c>] system_call_fastpath+0x26/0x2b
[  385.822449] ---[ end trace 5634bd9ec366973a ]---