sysfs group <address> not found for kobject 'target6:0:0'

When connecting a USB device or periodically while using my laptop I get the following error:

[ 3595.453994] ------------[ cut here ]------------
[ 3595.454008] WARNING: CPU: 2 PID: 7193 at /build/buildd/linux-3.13.0/fs/sysfs/group.c:214 sysfs_remove_group+0xc6/0xd0()
[ 3595.454011] sysfs group ffffffff81cab340 not found for kobject 'target6:0:0'
[ 3595.454013] Modules linked in: nls_iso8859_1 xt_conntrack ipt_REJECT ip6table_filter ip6_tables ebtable_nat ebtables overlayfs xt_CHECKSUM iptable_mangle ipt_MASQUERADE iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack xt_tcpudp bridge stp llc iptable_filter ip_tables x_tables ctr ccm rfcomm bnep binfmt_misc joydev uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_core videodev arc4 iwldvm mac80211 dm_multipath scsi_dh snd_hda_codec_hdmi snd_hda_codec_conexant snd_hda_intel snd_hda_codec snd_hwdep intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel snd_pcm kvm snd_page_alloc thinkpad_acpi nvram btusb bluetooth psmouse snd_seq_midi snd_seq_midi_event serio_raw snd_rawmidi iwlwifi cfg80211 snd_seq snd_seq_device snd_timer lpc_ich snd soundcore mac_hid mei_me mei lp parport dm_crypt usb_storage crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd i915 ahci libahci sdhci_pci sdhci e1000e i2c_algo_bit drm_kms_helper ptp drm pps_core wmi video
[ 3595.454106] CPU: 2 PID: 7193 Comm: umount Not tainted 3.13.0-19-generic #39-Ubuntu
[ 3595.454108] Hardware name: LENOVO 42872WU/42872WU, BIOS 8DET55WW (1.25 ) 11/01/2011
[ 3595.454111] 0000000000000009 ffff8802e0587b70 ffffffff81711075 ffff8802e0587bb8
[ 3595.454116] ffff8802e0587ba8 ffffffff810662cd 0000000000000000 ffffffff81cab340
[ 3595.454120] ffff88030689a838 ffff88030c8aa188 ffff880035f8e000 ffff8802e0587c08
[ 3595.454124] Call Trace:
[ 3595.454133] [<ffffffff81711075>] dump_stack+0x45/0x56
[ 3595.454138] [<ffffffff810662cd>] warn_slowpath_common+0x7d/0xa0
[ 3595.454142] [<ffffffff8106633c>] warn_slowpath_fmt+0x4c/0x50
[ 3595.454149] [<ffffffff8122ff0e>] ? sysfs_get_dirent_ns+0x4e/0x70
[ 3595.454153] [<ffffffff812311f6>] sysfs_remove_group+0xc6/0xd0
[ 3595.454159] [<ffffffff81490b03>] dpm_sysfs_remove+0x43/0x50
[ 3595.454164] [<ffffffff81486535>] device_del+0x45/0x1c0
[ 3595.454171] [<ffffffff814d8337>] scsi_target_reap_usercontext+0x27/0x40
[ 3595.454177] [<ffffffff81080ab7>] execute_in_process_context+0x67/0x70
[ 3595.454181] [<ffffffff814d9d04>] scsi_target_reap+0xc4/0xf0
[ 3595.454187] [<ffffffff814db8f8>] scsi_device_dev_release_usercontext+0x188/0x1c0
[ 3595.454191] [<ffffffff81080ab7>] execute_in_process_context+0x67/0x70
[ 3595.454196] [<ffffffff814db76c>] scsi_device_dev_release+0x1c/0x20
[ 3595.454200] [<ffffffff81485b82>] device_release+0x32/0xa0
[ 3595.454205] [<ffffffff8135b447>] kobject_cleanup+0x77/0x1b0
[ 3595.454209] [<ffffffff8135b2e8>] kobject_put+0x28/0x60
[ 3595.454215] [<ffffffff81485e77>] put_device+0x17/0x20
[ 3595.454219] [<ffffffff814cdcbb>] scsi_device_put+0x3b/0x50
[ 3595.454224] [<ffffffff814e2f60>] scsi_disk_put+0x30/0x50
[ 3595.454228] [<ffffffff814e3292>] sd_release+0x42/0xd0
[ 3595.454233] [<ffffffff811f25ec>] __blkdev_put+0x16c/0x1a0
[ 3595.454237] [<ffffffff811f258e>] __blkdev_put+0x10e/0x1a0
[ 3595.454241] [<ffffffff811f2f3e>] blkdev_put+0x4e/0x140
[ 3595.454246] [<ffffffff811badd4>] kill_block_super+0x44/0x70
[ 3595.454250] [<ffffffff811bb09d>] deactivate_locked_super+0x3d/0x60
[ 3595.454255] [<ffffffff811bb656>] deactivate_super+0x46/0x60
[ 3595.454259] [<ffffffff811d82c6>] mntput_no_expire+0xd6/0x170
[ 3595.454263] [<ffffffff811d97ae>] SyS_umount+0x8e/0x100
[ 3595.454268] [<ffffffff81721c7f>] tracesys+0xe1/0xe6
[ 3595.454271] ---[ end trace 5d2cb0f66a6a6ae8 ]---

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-19-generic 3.13.0-19.39
ProcVersionSignature: Ubuntu 3.13.0-19.39-generic 3.13.6
Uname: Linux 3.13.0-19-generic x86_64
ApportVersion: 2.13.3-0ubuntu1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: arges 3448 F.... pulseaudio
CurrentDesktop: Unity
Date: Tue Mar 25 09:01:46 2014
HibernationDevice: RESUME=UUID=a7b27ee5-508a-4f85-ba29-7630f0d2c8a5
InstallationDate: Installed on 2013-09-12 (193 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Alpha amd64 (20130912)
MachineType: LENOVO 42872WU
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-19-generic root=UUID=ebd9375f-99c8-45c6-bd4b-cc2a60f99efb ro quiet splash crashkernel=384M-:128M crashkernel=384M-:128M crashkernel=384M-:128M crashkernel=384M-:128M vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-19-generic N/A
 linux-backports-modules-3.13.0-19-generic N/A
 linux-firmware 1.126
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 11/01/2011
dmi.bios.vendor: LENOVO
dmi.bios.version: 8DET55WW (1.25 )
dmi.board.asset.tag: Not Available
dmi.board.name: 42872WU
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr8DET55WW(1.25):bd11/01/2011:svnLENOVO:pn42872WU:pvrThinkPadX220:rvnLENOVO:rn42872WU:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 42872WU
dmi.product.version: ThinkPad X220
dmi.sys.vendor: LENOVO