BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] __ticket_spin_lock+0x9/0x30 PGD 0 Oops: 0002 [#1] SMP CPU 1 Modules linked in: hidp hid bnep rfcomm parport_pc ppdev dm_crypt lp parport snd_hda_codec_realtek snd_hda_intel joydev snd_hda_codec mmc_block snd_hwdep snd_pcm arc4 snd_seq_midi snd_rawmidi b43 snd_seq_midi_event uvcvideo tifm_sd snd_seq videodev mac80211 psmouse pcmcia snd_timer snd_seq_device tifm_7xx1 btusb bluetooth snd v4l2_compat_ioctl32 tifm_core yenta_socket cfg80211 pcmcia_rsrc soundcore mac_hid dm_multipath pcmcia_core snd_page_alloc bcma serio_raw acer_wmi sparse_keymap squashfs overlayfs nls_iso8859_1 nls_cp437 vfat fat dm_raid45 xor dm_mirror dm_region_hash dm_log btrfs zlib_deflate libcrc32c i915 wmi drm_kms_helper drm i2c_algo_bit ssb video sky2 usb_storage Pid: 5618, comm: khidpd_04580058 Not tainted 3.2.0-14-generic #23-Ubuntu Acer, inc. Aspire 5570 /Prespa1 RIP: 0010:[] [] __ticket_spin_lock+0x9/0x30 RSP: 0018:ffff8800b3a75da0 EFLAGS: 00010086 RAX: 0000000000010000 RBX: 0000000000000286 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000286 RDI: 0000000000000000 RBP: ffff8800b3a75da0 R08: ffff8800b3a74000 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000001 R12: ffff8800b3a75e80 R13: ffff8800b3a75e98 R14: ffff8800b9601070 R15: ffff8800b9600000 FS: 0000000000000000(0000) GS:ffff8800bf500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000000 CR3: 0000000001c05000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process khidpd_04580058 (pid: 5618, threadinfo ffff8800b3a74000, task ffff8800b4e944a0) Stack: ffff8800b3a75db0 ffffffff8103cbb9 ffff8800b3a75dd0 ffffffff816578ee 0000000000000000 ffff8800b3a75e80 ffff8800b3a75e00 ffffffff81089ef1 ffff8800b3ffae00 0000000000000000 ffff8800b3ffae00 ffff8800b9600070 Call Trace: [] default_spin_lock_flags+0x9/0x10 [] _raw_spin_lock_irqsave+0x2e/0x40 [] finish_wait+0x41/0x80 [] hidp_session+0x3e6/0x510 [hidp] [] ? finish_task_switch+0x4a/0xf0 [] ? try_to_wake_up+0x200/0x200 [] ? try_to_wake_up+0x200/0x200 [] ? add_wait_queue+0x60/0x60 [] ? hidp_recv_ctrl_frame+0xf0/0xf0 [hidp] [] kthread+0x8c/0xa0 [] kernel_thread_helper+0x4/0x10 [] ? flush_kthread_worker+0xa0/0xa0 [] ? gs_change+0x13/0x13 Code: 00 00 48 c7 c1 11 c9 03 81 48 c7 c2 0e c9 03 81 e9 dd fe ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 55 b8 00 00 01 00 48 89 e5 0f c1 07 89 c2 c1 ea 10 66 39 c2 74 13 66 0f 1f 84 00 00 00 RIP [] __ticket_spin_lock+0x9/0x30 RSP CR2: 0000000000000000 ---[ end trace f1f9b0ddf985a25f ]---