> This could be a duplicate of bug 1372482
> 
> Can you post the errors you seen in /var/log/syslog?  

Alright, there's a trace message:

------------[ cut here ]------------
Sep 25 09:00:01 pi-behrens kernel: [  835.395138] WARNING: CPU: 0 PID: 4226 at /build/buildd/linux-3.13.0/fs/cifs/transport.c:313 smb_send_rqst+0x215/0x270 [cifs]()
Sep 25 09:00:01 pi-behrens kernel: [  835.395142] Send length mismatch(send_length=72 smb_buf_length=2164260932)
Sep 25 09:00:01 pi-behrens kernel: [  835.395144] Modules linked in: cfg80211 pci_stub vboxpci(OX) vboxnetadp(OX) vboxnetflt(OX) vboxdrv(OX) nls_utf8 cifs usblp snd_hda_codec_hdmi uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_core snd_usb_audio snd_usbmidi_lib videodev eeepc_wmi asus_wmi sparse_keymap snd_hda_codec_via nfsv4 rfcomm bnep snd_hda_intel snd_hda_codec bluetooth snd_hwdep snd_pcm intel_rapl snd_page_alloc x86_pkg_temp_thermal intel_powerclamp snd_seq_midi snd_seq_midi_event coretemp snd_rawmidi snd_seq kvm_intel kvm nfsd crct10dif_pclmul auth_rpcgss crc32_pclmul nfs_acl nfs ghash_clmulni_intel cryptd lockd sunrpc fscache serio_raw snd_seq_device snd_timer snd nouveau lpc_ich soundcore mxm_wmi ttm drm_kms_helper drm i2c_algo_bit ppdev parport_pc mei_me lp parport video wmi mac_hid mei hid_generic usbhid hid usb_storage ahci r8169 libahci mii
Sep 25 09:00:01 pi-behrens kernel: [  835.395241] CPU: 0 PID: 4226 Comm: mount.cifs Tainted: G        W  OX 3.13.0-36-generic #63-Ubuntu
Sep 25 09:00:01 pi-behrens kernel: [  835.395245] Hardware name: System manufacturer System Product Name/P8B75-M LX, BIOS 0803 10/10/2012
Sep 25 09:00:01 pi-behrens kernel: [  835.395248]  0000000000000009 ffff88011626dbb0 ffffffff8171e569 ffff88011626dbf8
Sep 25 09:00:01 pi-behrens kernel: [  835.395254]  ffff88011626dbe8 ffffffff8106775d ffff88011626dd00 ffff8800b428d000
Sep 25 09:00:01 pi-behrens kernel: [  835.395260]  ffff88011626dcc8 0000000000000001 0000000000000000 ffff88011626dc48
Sep 25 09:00:01 pi-behrens kernel: [  835.395265] Call Trace:
Sep 25 09:00:01 pi-behrens kernel: [  835.395273]  [<ffffffff8171e569>] dump_stack+0x45/0x56
Sep 25 09:00:01 pi-behrens kernel: [  835.395279]  [<ffffffff8106775d>] warn_slowpath_common+0x7d/0xa0
Sep 25 09:00:01 pi-behrens kernel: [  835.395284]  [<ffffffff810677cc>] warn_slowpath_fmt+0x4c/0x50
Sep 25 09:00:01 pi-behrens kernel: [  835.395299]  [<ffffffffa06e14c5>] smb_send_rqst+0x215/0x270 [cifs]
Sep 25 09:00:01 pi-behrens kernel: [  835.395307]  [<ffffffff81690218>] ? __inet_stream_connect+0x208/0x320
Sep 25 09:00:01 pi-behrens kernel: [  835.395319]  [<ffffffffa06e155d>] smb_sendv+0x3d/0x40 [cifs]
Sep 25 09:00:01 pi-behrens kernel: [  835.395330]  [<ffffffffa06e1588>] smb_send+0x28/0x30 [cifs]
Sep 25 09:00:01 pi-behrens kernel: [  835.395341]  [<ffffffffa06cb15d>] generic_ip_connect+0x30d/0x3e0 [cifs]
Sep 25 09:00:01 pi-behrens kernel: [  835.395348]  [<ffffffff811a1d65>] ? __kmalloc+0x55/0x230
Sep 25 09:00:01 pi-behrens kernel: [  835.395359]  [<ffffffffa06cf69c>] cifs_mount+0x85c/0xaf0 [cifs]
Sep 25 09:00:01 pi-behrens kernel: [  835.395368]  [<ffffffffa06be040>] cifs_do_mount+0xa0/0x4d0 [cifs]
Sep 25 09:00:01 pi-behrens kernel: [  835.395376]  [<ffffffff811c10a9>] mount_fs+0x39/0x1b0
Sep 25 09:00:01 pi-behrens kernel: [  835.395382]  [<ffffffff811dc447>] vfs_kern_mount+0x67/0x110
Sep 25 09:00:01 pi-behrens kernel: [  835.395387]  [<ffffffff811deca4>] do_mount+0x244/0xb20
Sep 25 09:00:01 pi-behrens kernel: [  835.395393]  [<ffffffff811530be>] ? __get_free_pages+0xe/0x50
Sep 25 09:00:01 pi-behrens kernel: [  835.395398]  [<ffffffff811de8e6>] ? copy_mount_options+0x36/0x170
Sep 25 09:00:01 pi-behrens kernel: [  835.395403]  [<ffffffff811df873>] SyS_mount+0x83/0xc0
Sep 25 09:00:01 pi-behrens kernel: [  835.395409]  [<ffffffff8172efad>] system_call_fastpath+0x1a/0x1f
Sep 25 09:00:01 pi-behrens kernel: [  835.395412] ---[ end trace 3ec5a8fa5f0c83a7 ]---
Sep 25 09:00:01 pi-behrens kernel: [  835.397427] CIFS VFS: Error connecting to socket. Aborting operation.
Sep 25 09:00:01 pi-behrens kernel: [  835.397569] CIFS VFS: cifs_mount failed w/return code = -5

> Also, there is a test kernel in bug 1372482 you could try:
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1372482/comments/12

Yep, will try.