The issue persists with the mainline kernel:

Feb  5 09:59:56 fourish kernel: [   93.307359] BUG: unable to handle kernel NULL pointer dereference at 00000280
Feb  5 09:59:56 fourish kernel: [   93.307587] IP: [<f868f7b4>] hci_send_sco+0x14/0x80 [bluetooth]
Feb  5 09:59:56 fourish kernel: [   93.307780] *pdpt = 0000000020d51001 *pde = 0000000000000000 
Feb  5 09:59:56 fourish kernel: [   93.307945] Oops: 0000 [#1] SMP 
Feb  5 09:59:56 fourish kernel: [   93.308019] Modules linked in: btusb snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep snd_pcm coretemp snd_page_alloc snd_seq_midi snd_seq_midi_event snd_rawmidi dell_laptop arc4 compal_laptop uvcvideo snd_seq videobuf2_vmalloc dcdbas b43 videobuf2_memops bcma i915 videobuf2_core snd_seq_device mac80211 psmouse ath3k snd_timer videodev drm_kms_helper microcode lpc_ich joydev snd jmb38x_ms drm serio_raw memstick cfg80211 soundcore i2c_algo_bit video mac_hid bnep rfcomm bluetooth parport_pc ppdev binfmt_misc lp parport hid_logitech ff_memless usbhid hid ssb r8169 sdhci_pci sdhci
Feb  5 09:59:56 fourish kernel: [   93.308019] Pid: 2091, comm: bluetooth Not tainted 3.8.0-030800rc6-generic #201301312135 Dell Inc. Inspiron 910/      
Feb  5 09:59:56 fourish kernel: [   93.308019] EIP: 0060:[<f868f7b4>] EFLAGS: 00010282 CPU: 0
Feb  5 09:59:56 fourish kernel: [   93.308019] EIP is at hci_send_sco+0x14/0x80 [bluetooth]
Feb  5 09:59:56 fourish kernel: [   93.308019] EAX: 00000000 EBX: e0fc8c00 ECX: da7422a0 EDX: e0fc8c00
Feb  5 09:59:56 fourish kernel: [   93.308019] ESI: 00000030 EDI: da679eac EBP: da679d68 ESP: da679d54
Feb  5 09:59:56 fourish kernel: [   93.308019]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Feb  5 09:59:56 fourish kernel: [   93.308019] CR0: 80050033 CR2: 00000280 CR3: 2172c000 CR4: 000007e0
Feb  5 09:59:56 fourish kernel: [   93.308019] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
Feb  5 09:59:56 fourish kernel: [   93.308019] DR6: ffff0ff0 DR7: 00000400
Feb  5 09:59:56 fourish kernel: [   93.308019] Process bluetooth (pid: 2091, ti=da678000 task=da63b340 task.ti=da678000)
Feb  5 09:59:56 fourish kernel: [   93.308019] Stack:
Feb  5 09:59:56 fourish kernel: [   93.308019]  c153092f e0fc8838 e0fc8c00 00000030 da679eac da679d8c f86ae7b3 da679d7c
Feb  5 09:59:56 fourish kernel: [   93.308019]  da679e98 da7422a0 00000000 e0e0fc00 da679e90 ffffff95 da679da4 f86aef23
Feb  5 09:59:56 fourish kernel: [   93.308019]  00000030 f86b2d00 d7fa0780 da679e34 da679e80 c1524d41 00000030 00000030
Feb  5 09:59:56 fourish kernel: [   93.308019] Call Trace:
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c153092f>] ? memcpy_fromiovec+0x3f/0x70
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<f86ae7b3>] sco_send_frame.isra.2+0xc3/0x120 [bluetooth]
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<f86aef23>] sco_sock_sendmsg+0x73/0x90 [bluetooth]
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c1524d41>] sock_sendmsg+0xd1/0xf0
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c10875ec>] ? enqueue_task_fair+0x5cc/0x7b0
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c10bca19>] ? __stop_machine+0x99/0xd0
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c1526a9e>] sys_sendto+0x10e/0x150
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c107c36c>] ? ttwu_queue+0xac/0xc0
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c107e380>] ? try_to_wake_up+0x140/0x190
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c107e3ff>] ? wake_up_state+0xf/0x20
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c10a5c25>] ? wake_futex+0x75/0xa0
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c10a6d06>] ? futex_wake+0xf6/0x110
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c1526b1b>] sys_send+0x3b/0x40
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c1527482>] sys_socketcall+0x182/0x2e0
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c12f50e0>] ? copy_to_user+0x40/0x60
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c106c4c8>] ? sys_clock_gettime+0x48/0x70
Feb  5 09:59:56 fourish kernel: [   93.308019]  [<c162e18d>] sysenter_do_call+0x12/0x28
Feb  5 09:59:56 fourish kernel: [   93.308019] Code: 43 6d 9d c8 8b 5d f4 8b 75 f8 8b 7d fc 89 ec 5d c3 8d b6 00 00 00 00 55 89 e5 83 ec 14 89 5d f4 89 75 f8 89 7d fc 3e 8d 74 26 00 <8b> b8 80 02 00 00 0f b7 48 14 89 c6 8b 42 50 89 d3 ba 03 00 00
Feb  5 09:59:56 fourish kernel: [   93.308019] EIP: [<f868f7b4>] hci_send_sco+0x14/0x80 [bluetooth] SS:ESP 0068:da679d54
Feb  5 09:59:56 fourish kernel: [   93.308019] CR2: 0000000000000280
Feb  5 09:59:56 fourish kernel: [   93.400821] ---[ end trace 93bf018dc370c403 ]---
Feb  5 10:01:03 fourish kernel: [  160.216297] Bluetooth: hci0 SCO packet for unknown connection handle 65531
Feb  5 10:01:03 fourish kernel: [  160.216314] Bluetooth: hci0 SCO packet for unknown connection handle 65527
Feb  5 10:01:03 fourish kernel: [  160.236292] Bluetooth: hci0 SCO packet for unknown connection handle 59135
Feb  5 10:01:03 fourish kernel: [  160.236311] Bluetooth: hci0 SCO packet for unknown connection handle 14
(...)