virtualbox and kern.log growing to infinity

[Luca Ferrari]

Hi all,
I'm running wily 15.10, and today I ran out of my log partition space.
After a few analysis I found a kern.log file grown more than 8 GB in a
single day.
I can see a lot of trace added to the file while virtual box
5.0.0r101573 is running windows 7 guest:

Nov 23 16:37:42 fluca kernel: [30169.352134] ------------[ cut here
]------------
Nov 23 16:37:42 fluca kernel: [30169.352148] WARNING: CPU: 1 PID:
11994 at /build/linux-AxjFAn/linux-4.2.0/kernel/sched/core.c:2342
preempt_notifier_register+0x2e/0x70()
Nov 23 16:37:42 fluca kernel: [30169.352150] registering
preempt_notifier while notifiers disabled
Nov 23 16:37:42 fluca kernel: [30169.352152] Modules linked in:
pci_stub vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) vboxdrv(OE) xts
gf128mul nls_iso8859_1 uas usb_storage binfmt_misc
snd_hda_codec_realtek snd_hda_codec_generic drbg ansi_cprng dm_crypt
input_leds snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep kvm_amd
snd_pcm kvm serio_raw snd_seq_midi snd_seq_midi_event snd_rawmidi
k8temp snd_seq edac_core edac_mce_amd shpchp snd_seq_device snd_timer
snd soundcore i2c_nforce2 asus_atk0110 mac_hid 8250_fintek parport_pc
ppdev lp parport autofs4 hid_generic usbhid hid pata_acpi amdkfd
amd_iommu_v2 radeon i2c_algo_bit ttm drm_kms_helper drm psmouse
forcedeth ahci libahci pata_amd video floppy
Nov 23 16:37:42 fluca kernel: [30169.352202] CPU: 1 PID: 11994 Comm:
EMT Tainted: G        W  OE   4.2.0-16-generic #19-Ubuntu
Nov 23 16:37:42 fluca kernel: [30169.352205] Hardware name: Olidata
S.p.A. APM78-GS/APM78-GS_S, BIOS 0013    04/17/2009
Nov 23 16:37:42 fluca kernel: [30169.352207]  0000000000000000
00000000d96ba82d ffff880019173ca8 ffffffff817e8c09
Nov 23 16:37:42 fluca kernel: [30169.352210]  0000000000000000
ffff880019173d00 ffff880019173ce8 ffffffff8107b3c6
Nov 23 16:37:42 fluca kernel: [30169.352213]  ffff880123b98c10
ffff88002a2769a0 0000000000000001 ffffc90002bd0000
Nov 23 16:37:42 fluca kernel: [30169.352216] Call Trace:
Nov 23 16:37:42 fluca kernel: [30169.352223]  [<ffffffff817e8c09>]
dump_stack+0x45/0x57
Nov 23 16:37:42 fluca kernel: [30169.352236]  [<ffffffff8107b3c6>]
warn_slowpath_common+0x86/0xc0
Nov 23 16:37:42 fluca kernel: [30169.352240]  [<ffffffff8107b455>]
warn_slowpath_fmt+0x55/0x70
Nov 23 16:37:42 fluca kernel: [30169.352243]  [<ffffffff8109fb3e>]
preempt_notifier_register+0x2e/0x70
Nov 23 16:37:42 fluca kernel: [30169.352273]  [<ffffffffc054cc75>]
VBoxHost_RTThreadCtxHookEnable+0x35/0x40 [vboxdrv]
Nov 23 16:37:42 fluca kernel: [30169.352287]  [<ffffffffc053984f>] ?
supdrvIOCtlFast+0x8f/0xa0 [vboxdrv]
Nov 23 16:37:42 fluca kernel: [30169.352299]  [<ffffffffc05364aa>] ?
VBoxDrvLinuxIOCtl_5_0_0+0x5a/0x240 [vboxdrv]
Nov 23 16:37:42 fluca kernel: [30169.352304]  [<ffffffff812108a5>] ?
do_vfs_ioctl+0x295/0x480
Nov 23 16:37:42 fluca kernel: [30169.352307]  [<ffffffff81210b09>] ?
SyS_ioctl+0x79/0x90
Nov 23 16:37:42 fluca kernel: [30169.352312]  [<ffffffff817ef9f2>] ?
entry_SYSCALL_64_fastpath+0x16/0x75
Nov 23 16:37:42 fluca kernel: [30169.352315] ---[ end trace
a1766bbd8c7c2f34 ]---
Nov 23 16:37:42 fluca kernel: [30169.360718] ------------[ cut here
]------------
Nov 23 16:37:42 fluca kernel: [30169.360728] WARNING: CPU: 0 PID:
11994 at /build/linux-AxjFAn/linux-4.2.0/kernel/sched/core.c:2342
preempt_notifier_register+0x2e/0x70()
Nov 23 16:37:42 fluca kernel: [30169.360730] registering
preempt_notifier while notifiers disabled
Nov 23 16:37:42 fluca kernel: [30169.360732] Modules linked in:
pci_stub vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) vboxdrv(OE) xts
gf128mul nls_iso8859_1 uas usb_storage binfmt_misc
snd_hda_codec_realtek snd_hda_codec_generic drbg ansi_cprng dm_crypt
input_leds snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep kvm_amd
snd_pcm kvm serio_raw snd_seq_midi snd_seq_midi_event snd_rawmidi
k8temp snd_seq edac_core edac_mce_amd shpchp snd_seq_device snd_timer
snd soundcore i2c_nforce2 asus_atk0110 mac_hid 8250_fintek parport_pc
ppdev lp parport autofs4 hid_generic usbhid hid pata_acpi amdkfd
amd_iommu_v2 radeon i2c_algo_bit ttm drm_kms_helper drm psmouse
forcedeth ahci libahci pata_amd video floppy
Nov 23 16:37:42 fluca kernel: [30169.360779] CPU: 0 PID: 11994 Comm:
EMT Tainted: G        W  OE   4.2.0-16-generic #19-Ubuntu
Nov 23 16:37:42 fluca kernel: [30169.360781] Hardware name: Olidata
S.p.A. APM78-GS/APM78-GS_S, BIOS 0013    04/17/2009
Nov 23 16:37:42 fluca kernel: [30169.360784]  0000000000000000
00000000d96ba82d ffff880019173ca8 ffffffff817e8c09
Nov 23 16:37:42 fluca kernel: [30169.360787]  0000000000000000
ffff880019173d00 ffff880019173ce8 ffffffff8107b3c6
Nov 23 16:37:42 fluca kernel: [30169.360790]  0000000000000000
ffff88002a2769a0 0000000000000001 ffffc90002bd0000
Nov 23 16:37:42 fluca kernel: [30169.360793] Call Trace:
Nov 23 16:37:42 fluca kernel: [30169.360799]  [<ffffffff817e8c09>]
dump_stack+0x45/0x57
Nov 23 16:37:42 fluca kernel: [30169.360804]  [<ffffffff8107b3c6>]
warn_slowpath_common+0x86/0xc0
Nov 23 16:37:42 fluca kernel: [30169.360807]  [<ffffffff8107b455>]
warn_slowpath_fmt+0x55/0x70
Nov 23 16:37:42 fluca kernel: [30169.360810]  [<ffffffff8109fb3e>]
preempt_notifier_register+0x2e/0x70
Nov 23 16:37:42 fluca kernel: [30169.360838]  [<ffffffffc054cc75>]
VBoxHost_RTThreadCtxHookEnable+0x35/0x40 [vboxdrv]
Nov 23 16:37:42 fluca kernel: [30169.360852]  [<ffffffffc053984f>] ?
supdrvIOCtlFast+0x8f/0xa0 [vboxdrv]
Nov 23 16:37:42 fluca kernel: [30169.360865]  [<ffffffffc05364aa>] ?
VBoxDrvLinuxIOCtl_5_0_0+0x5a/0x240 [vboxdrv]
Nov 23 16:37:42 fluca kernel: [30169.360869]  [<ffffffff812108a5>] ?
do_vfs_ioctl+0x295/0x480
Nov 23 16:37:42 fluca kernel: [30169.360873]  [<ffffffff8121a3c6>] ?
__fget+0x26/0x90
Nov 23 16:37:42 fluca kernel: [30169.360876]  [<ffffffff81210b09>] ?
SyS_ioctl+0x79/0x90
Nov 23 16:37:42 fluca kernel: [30169.360881]  [<ffffffff817ef9f2>] ?
entry_SYSCALL_64_fastpath+0x16/0x75
Nov 23 16:37:42 fluca kernel: [30169.360883] ---[ end trace
a1766bbd8c7c2f35 ]---
Nov 23 16:37:42 fluca kernel: [30169.362170] ------------[ cut here
]------------
Nov 23 16:37:42 fluca kernel: [30169.362182] WARNING: CPU: 0 PID:
11994 at /build/linux-AxjFAn/linux-4.2.0/kernel/sched/core.c:2342
preempt_notifier_register+0x2e/0x70()
Nov 23 16:37:42 fluca kernel: [30169.362184] registering
preempt_notifier while notifiers disabled
Nov 23 16:37:42 fluca kernel: [30169.362186] Modules linked in:
pci_stub vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) vboxdrv(OE) xts
gf128mul nls_iso8859_1 uas usb_storage binfmt_misc
snd_hda_codec_realtek snd_hda_codec_generic drbg ansi_cprng dm_crypt
input_leds snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep kvm_amd
snd_pcm kvm serio_raw snd_seq_midi snd_seq_midi_event snd_rawmidi
k8temp snd_seq edac_core edac_mce_amd shpchp snd_seq_device snd_timer
snd soundcore i2c_nforce2 asus_atk0110 mac_hid 8250_fintek parport_pc
ppdev lp parport autofs4 hid_generic usbhid hid pata_acpi amdkfd
amd_iommu_v2 radeon i2c_algo_bit ttm drm_kms_helper drm psmouse
forcedeth ahci libahci pata_amd video floppy
Nov 23 16:37:42 fluca kernel: [30169.362263] CPU: 0 PID: 1199


Anyone can give me an explaination about what the hell is happening?
Thanks,
Luca