BUG: unable to handle kernel paging request at ffffec2000000900
IP: [<ffffffff811c2046>] kfree+0x56/0x150
PGD 0 
Oops: 0000 [#1] SMP 
Modules linked in: kvm_amd kvm arc4 ath9k snd_hda_codec_realtek snd_hda_codec_generic snd_hda_codec_hdmi ath9k_common joydev ath9k_hw ath serio_raw mac80211 snd_hda_intel snd_hda_controller snd_seq_midi snd_seq_midi_event snd_hda_codec k10temp snd_hwdep snd_rawmidi snd_pcm rfcomm bnep cfg80211 snd_seq bluetooth 6lowpan_iphc radeon snd_seq_device snd_timer sp5100_tco i2c_piix4 ttm drm_kms_helper snd drm soundcore shpchp i2c_algo_bit mac_hid parport_pc ppdev lp parport hwmon_vid pata_acpi hid_generic usbhid hid psmouse r8169 mii pata_atiixp ahci libahci
CPU: 1 PID: 1377 Comm: Xorg Not tainted 3.16.0-26-generic #34-Ubuntu
Hardware name: MotherBoard By ZOTAC MotherBoard Fusion350-B-B/E/J/U/Fusion350-B-B/E/J/U, BIOS 4.6.4 11/14/2011
task: ffff880092a7d180 ti: ffff880236828000 task.ti: ffff880236828000
RIP: 0010:[<ffffffff811c2046>]  [<ffffffff811c2046>] kfree+0x56/0x150
RSP: 0000:ffff88023682b9b8  EFLAGS: 00010286
RAX: 0000022000000900 RBX: 0000100000024414 RCX: 0000000000000000
RDX: 000077ff80000000 RSI: 0000000000005f78 RDI: 0000100000024414
RBP: ffff88023682b9d0 R08: 0000000000000003 R09: ffffec2000000900
R10: 0000000000000036 R11: 0000000000000000 R12: ffff880092e6c000
R13: ffffffffc02964f7 R14: ffff880092375a00 R15: 0000000000000c00
FS:  00007f81882499c0(0000) GS:ffff88024ed00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffec2000000900 CR3: 0000000092ad2000 CR4: 00000000000007e0
Stack:
 ffff880092e6c000 ffff880092e6c000 0000000000000000 ffff88023682ba98
 ffffffffc02964f7 0000000292375a00 ffff880092e45000 00007c4800007d2c
 ffff880000007c44 ffff880092374600 ffff880092b2a900 0000100000024414
Call Trace:
 [<ffffffffc02964f7>] evergreen_hdmi_setmode+0x8d7/0xbd0 [radeon]
 [<ffffffffc017ecf4>] ? drm_detect_hdmi_monitor+0x74/0xc0 [drm]
 [<ffffffffc029db58>] radeon_atom_encoder_mode_set+0x158/0x2d0 [radeon]
 [<ffffffffc01b4966>] drm_crtc_helper_set_mode+0x356/0x530 [drm_kms_helper]
 [<ffffffffc01b56db>] drm_crtc_helper_set_config+0x98b/0xb10 [drm_kms_helper]
 [<ffffffff8139c971>] ? idr_mark_full+0x61/0x70
 [<ffffffffc0248d64>] radeon_crtc_set_config+0x44/0x120 [radeon]
 [<ffffffffc01766d1>] drm_mode_set_config_internal+0x61/0xe0 [drm]
 [<ffffffffc017a413>] drm_mode_setcrtc+0x283/0x580 [drm]
 [<ffffffffc016aa4f>] drm_ioctl+0x1df/0x680 [drm]
 [<ffffffffc022004c>] radeon_drm_ioctl+0x4c/0x80 [radeon]
 [<ffffffff811f5138>] do_vfs_ioctl+0x2c8/0x4a0
 [<ffffffff811f5391>] SyS_ioctl+0x81/0xa0
 [<ffffffff81789ead>] system_call_fastpath+0x1a/0x1f
Code: 00 00 00 80 ff 77 00 00 49 b9 00 00 00 00 00 ea ff ff 48 01 d8 48 0f 42 15 d8 7f a5 00 48 01 d0 48 c1 e8 0c 48 c1 e0 06 49 01 c1 <49> 8b 01 f6 c4 80 0f 85 b6 00 00 00 49 8b 01 a8 80 0f 84 83 00