Trusty kernel is unable to page Evergreen Radeon GPU; blank screen and high load after boot

[ATAKAMA]

lsb_release -rd
Description: Ubuntu 14.04.1 LTS
Release: 14.04

apt-cache policy linux-signed-generic
linux-signed-generic:
  Installed: 3.13.0.43.50
  Candidate: 3.13.0.43.50
  Version table:
 *** 3.13.0.43.50 0
        500 http://ro.archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ trusty-security/main amd64 Packages
        100 /var/lib/dpkg/status
     3.13.0.24.28 0
        500 http://ro.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

Expected behavior: see lightdm login screen after boot

Actual behavior:
After a kernel update to 3.13.0-43, a machine with an Evergreen Radeon GPU is no longer usable. After showing the splash screen, the monitor doesn't detect any signal and goes blank. Furthermore, the system load increases above 2.5 without any CPU or IO activity.
This bug is similar to bug #1397553 for Utopic.

EDIT: The bug only surfaces when a monitor is connected via HDMI. If the HDMI connector is unplugged, the system boots fine.

Relevant syslog:

[ 0.000000] Linux version 3.13.0-43-generic (buildd@tipua) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1) ) #72-Ubuntu SMP Mon Dec 8 19:35:06 UTC 2014 (Ubuntu 3.13.0-43.72-generic 3.13.11.11)
[ 32.934494] BUG: unable to handle kernel paging request at ffffec2000000900
[ 32.934592] IP: [<ffffffff811a2046>] kfree+0x56/0x140
[ 32.934655] PGD 0
[ 32.934683] Oops: 0000 [#1] SMP
[ 32.934726] Modules linked in: bnep rfcomm snd_hda_codec_realtek snd_hda_codec_hdmi hid_generic snd_hda_intel usbhid kvm_amd hid snd_hda_codec snd_hwdep snd_pcm snd_page_alloc snd_seq_midi snd_seq_midi_event snd_rawmidi kvm snd_seq snd_seq_device snd_timer radeon serio_raw snd btusb soundcore ttm drm_kms_helper k10temp bluetooth sp5100_tco drm i2c_algo_bit i2c_piix4 mac_hid parport_pc ppdev f71882fg lp parport nls_iso8859_1 pata_acpi psmouse r8169 mii pata_atiixp ahci libahci
[ 32.935304] CPU: 0 PID: 1523 Comm: Xorg Not tainted 3.13.0-43-generic #72-Ubuntu
[ 32.935384] Hardware name: MSI MS-7698/E350IA-E44 (MS-7698), BIOS V1.5 04/22/2011
[ 32.935458] task: ffff880232b3c800 ti: ffff880232b34000 task.ti: ffff880232b34000
[ 32.935532] RIP: 0010:[<ffffffff811a2046>] [<ffffffff811a2046>] kfree+0x56/0x140
[ 32.935612] RSP: 0018:ffff880232b35a68 EFLAGS: 00010286
[ 32.935669] RAX: ffffec2000000900 RBX: 0000100000024414 RCX: 0000000000000000
[ 32.935739] RDX: ffffea0000000000 RSI: 0000000000005f78 RDI: 0000100000024414
[ 32.935809] RBP: ffff880232b35a80 R08: 0000000000000022 R09: 0000000000000021
[ 32.935879] R10: ffffea0008ca1dc0 R11: ffffffffa0292bc1 R12: 0000000000000000
[ 32.935949] R13: ffffffffa02ef3b6 R14: 0000000000000000 R15: ffff880231c95e00
[ 32.936021] FS: 00007f47050109c0(0000) GS:ffff88023ec00000(0000) knlGS:0000000000000000
[ 32.936106] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 32.936163] CR2: ffffec2000000900 CR3: 0000000231123000 CR4: 00000000000007f0
[ 32.936234] Stack:
[ 32.936257] ffff880036784000 0000000000000000 ffff880036784000 ffff880232b35b38
[ 32.936345] ffffffffa02ef3b6 ffff880232b35ab0 ffff880200007048 000070440000712c
[ 32.936431] ffff880001f7d000 0000100000024414 0000188000024414 0000180000028488
[ 32.936518] Call Trace:
[ 32.936605] [<ffffffffa02ef3b6>] evergreen_hdmi_setmode+0x776/0x960 [radeon]
[ 32.936707] [<ffffffffa00bb55e>] ? drm_detect_hdmi_monitor+0x6e/0xb0 [drm]
[ 32.936814] [<ffffffffa02f6788>] radeon_atom_encoder_mode_set+0x158/0x2d0 [radeon]
[ 32.936897] [<ffffffffa0150a98>] drm_crtc_helper_set_mode+0x498/0x500 [drm_kms_helper]
[ 32.937004] [<ffffffffa02a0d35>] radeon_property_change_mode.isra.1+0x35/0x40 [radeon]
[ 32.937109] [<ffffffffa02a0ece>] radeon_connector_set_property+0x18e/0x300 [radeon]
[ 32.937209] [<ffffffffa00b8732>] drm_mode_obj_set_property_ioctl+0x142/0x340 [drm]
[ 32.937300] [<ffffffffa00b8960>] drm_mode_connector_property_set_ioctl+0x30/0x40 [drm]
[ 32.937391] [<ffffffffa00a7c22>] drm_ioctl+0x502/0x630 [drm]
[ 32.937456] [<ffffffff8172cc94>] ? __do_page_fault+0x204/0x560
[ 32.937534] [<ffffffffa02620fe>] radeon_drm_ioctl+0x4e/0x90 [radeon]
[ 32.937602] [<ffffffff811d0e90>] do_vfs_ioctl+0x2e0/0x4c0
[ 32.937664] [<ffffffff811c01b1>] ? __sb_end_write+0x31/0x60
[ 32.937727] [<ffffffff811d10f1>] SyS_ioctl+0x81/0xa0
[ 32.937781] [<ffffffff817316ad>] system_call_fastpath+0x1a/0x1f
[ 32.937844] Code: 00 00 00 80 ff 77 00 00 48 01 d8 48 0f 42 15 e2 2f a7 00 48 01 d0 48 ba 00 00 00 00 00 ea ff ff 48 c1 e8 0c 48 c1 e0 06 48 01 d0 <48> 8b 10 80 e6 80 0f 85 be 00 00 00 49 89 c2 49 8b 02 a8 80 0f
[ 32.938231] RIP [<ffffffff811a2046>] kfree+0x56/0x140
[ 32.938293] RSP <ffff880232b35a68>
[ 32.938330] CR2: ffffec2000000900

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1404560

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[penalvch (penalvch)]

ATAKAMA, could you please boot into a live environment via http://cdimage.ubuntu.com/daily-live/current/ and gather the information requested https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1404560/comments/2 ?

[penalvch (penalvch)]

ATAKAMA, could you please execute the following command via a terminal (not attach the file manually):
apport-collect 1404560

[ATAKAMA (atakama)]

I did run apport-collect 1404560, then it prompted me to choose what to do with the report, I chose Keep the local file and then I uploaded it.

[ATAKAMA (atakama)]

Kernel bug report: https://bugzilla.kernel.org/show_bug.cgi?id=88481
The fix is here: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=83d04c39f9048807a8500e575ae3f1718a3f45bb

[ATAKAMA (atakama)]

Fixed in kernel 3.13.0-44, package version 3.13.0.44.51. Bug report can be closed.

[penalvch (penalvch)]

ATAKAMA, this bug report is being closed due to your last comment https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1404560/comments/8 regarding this being fixed with an update. For future reference you can manage the status of your own bugs by clicking on the current status in the yellow line and then choosing a new status in the revealed drop down box. You can learn more about bug statuses at https://wiki.ubuntu.com/Bugs/Status. Thank you again for taking the time to report this bug and helping to make Ubuntu better. Please submit any future bugs you may find.