nouveau driver fills syslog when running xscreensaver (molecule)

[Olivier Diotte]

nouveau fills /var/log/kern.log and /var/log/syslog with _very_ frequent messages when the molecule xscreensaver is running.
This is a big problem as it prevents me from letting my machine do anything overnight (with the screenlock on).

I haven't tested other screensavers and don't appear to get messages otherwise. Here is an excerpt:

====================8< CUT HERE 8<=================================================================
$ tail -n 3000 kern.log.1 | head -n 50
Jul 10 18:02:35 dioo-XPS kernel: [114893.357149] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.406261] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.406269] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.420442] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.420447] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.479210] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.479217] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.568349] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.568356] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.622806] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.622813] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.637217] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.637221] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.695836] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.695843] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.784309] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.784316] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.838180] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.838187] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.853754] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.853759] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.913521] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.913528] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.977242] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.977249] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114894.068780] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114894.068788] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114894.122599] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114894.122606] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114894.137025] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114894.137030] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114894.195675] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114894.195682] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:36 dioo-XPS kernel: [114894.284069] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:36 dioo-XPS kernel: [114894.284078] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:36 dioo-XPS kernel: [114894.339830] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:36 dioo-XPS kernel: [114894.339837] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:36 dioo-XPS kernel: [114894.353411] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:36 dioo-XPS kernel: [114894.353416] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:36 dioo-XPS kernel: [114894.412188] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:36 dioo-XPS kernel: [114894.412204] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:36 dioo-XPS kernel: [114894.501906] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:36 dioo-XPS kernel: [114894.501913] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:36 dioo-XPS kernel: [114894.558826] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:36 dioo-XPS kernel: [114894.558831] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:36 dioo-XPS kernel: [114894.570001] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:36 dioo-XPS kernel: [114894.570006] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:36 dioo-XPS kernel: [114894.628831] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:36 dioo-XPS kernel: [114894.628839] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:36 dioo-XPS kernel: [114894.717193] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
====================8< CUT HERE 8<==================================================================

Both log files are actually 99GiB (they'd be bigger, but at that point my / partition was full). Both files contain almost 975M lines each (which is quite a lot for a file that gets rotated daily!)

I run a minimal system (log in to the console, start i3 with startx) and I have a keybinding to launch a xscreensaver (specifically the molecule screensaver from xscreensaver-gl-extra).

I had no problem under Ubuntu 15.04 32 bits, but for work-related reasons, I had to downgrade to 14.04 (64 bits).

Both the default kernel (I don't remember which version it was) and 3.19.0-22 exhibit the problem.

$ lspci -nn | grep VGA
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation Device [10de:1286] (rev a1)

I am not sure if this is relevant, but I have three screens all connected to the nVidia card.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.19.0-22-generic 3.19.0-22.22~14.04.1
ProcVersionSignature: Ubuntu 3.19.0-22.22~14.04.1-generic 3.19.8-ckt1
Uname: Linux 3.19.0-22-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.11
Architecture: amd64
Date: Tue Jul 14 15:31:42 2015
InstallationDate: Installed on 2015-07-03 (10 days ago)
InstallationMedia: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release amd64 (20150218.1)
SourcePackage: linux-lts-vivid
UpgradeStatus: No upgrade log present (probably fresh install)

[Vincent Lefevre (vincent-vinc17-net)]

FYI, I have the same kind of messages on my Debian machine when playing videos. I've reported a bug upstream: https://bugs.freedesktop.org/show_bug.cgi?id=91355

[Olivier Diotte (vhann3000)]

Based on the comment by Ilia Mirkin in Vincent's bug, I tested the current mainline (4.2.0-rc2) using Ubuntu's config (more or less following the procedure here https://wiki.ubuntu.com/KernelTeam/GitKernelBuild ).

I xscreensaver-command -lock, then logged back in (no issue there), then I xscreensaver-command -lock again and the computer just locked up. Caps lock light was unresponsive on the keyboard, Ctrl+Alt+Delete didn't work, RESIUB magic keys either.

After hard rebooting the computer, here is what what in kern.log and syslog:

Jul 16 17:19:45 dioo-XPS rtkit-daemon[2678]: Supervising 4 threads of 1 processes of 1 users.
Jul 16 17:27:15 dioo-XPS kernel: [ 619.825758] nouveau E[ PFIFO][0000:01:00.0] SCHED_ERROR [ CTXSW_TIMEOUT ]
Jul 16 17:27:15 dioo-XPS kernel: [ 619.825764] nouveau E[ PFIFO][0000:01:00.0] PGRAPH engine fault on channel 2, recovering...
Jul 16 17:28:35 dioo-XPS dbus[894]: [system] Activating service name='org.freedesktop.systemd1' (using servicehelper)

[Vhann3000+freedesktop (vhann3000+freedesktop)]

On Ubuntu 14.04.2, with both the stock kernel and 3.19.0-22, nouveau fills kern.log with messages like these:

====================8< CUT HERE 8<=================================================================
$ tail -n 3000 kern.log.1 | head -n 50
Jul 10 18:02:35 dioo-XPS kernel: [114893.357149] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.406261] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.406269] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.420442] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.420447] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.479210] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.479217] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.568349] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.568356] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.622806] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.622813] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.637217] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.637221] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.695836] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.695843] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.784309] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.784316] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.838180] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.838187] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.853754] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.853759] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.913521] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.913528] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 [Xorg[16558]] subc 5 mthd 0x0000 data 0x0000906e
Jul 10 18:02:35 dioo-XPS kernel: [114893.977242] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: LBREQ
Jul 10 18:02:35 dioo-XPS kernel: [114893.977249] nouveau E[ PFIFO][0000:01:00.0] PBDMA0: ch 2 ...

[Olivier Diotte (vhann3000)]

Bug filed upstream https://bugs.freedesktop.org/show_bug.cgi?id=91373

[Vhann3000+freedesktop (vhann3000+freedesktop)]

Looks much better on v3.19.

The computer didn't lock up after 3 xscreensaver-command -lock.

Interestingly though, on the HDMI screen, the first time, the molecule wasn't rotating and error messages appeared. This was in dmesg:

[ 131.177645] nouveau E[ PFIFO][0000:01:00.0] SCHED_ERROR [ CTXSW_TIMEOUT ]
[ 131.177651] nouveau E[ PFIFO][0000:01:00.0] PGRAPH engine fault on channel 7, recovering...
[ 160.403618] nouveau E[molecule[2408]] failed to idle channel 0xcccc0000 [molecule[2408]]
[ 175.398186] nouveau E[molecule[2408]] failed to idle channel 0xcccc0000 [molecule[2408]]

Didn't get any error since, still testing.

[Vhann3000+freedesktop (vhann3000+freedesktop)]

v3.19 is no go.

============8< CUT HERE 8<======================
$ grep 'nouveau' /var/log/syslog | head -n 100
Jul 17 10:48:09 dioo-XPS kernel: [ 5.463520] fb: switching to nouveaufb from VESA VGA
Jul 17 10:48:09 dioo-XPS kernel: [ 5.465859] nouveau [ DEVICE][0000:01:00.0] BOOT0 : 0x108060a1
Jul 17 10:48:09 dioo-XPS kernel: [ 5.465862] nouveau [ DEVICE][0000:01:00.0] Chipset: GK208 (NV108)
Jul 17 10:48:09 dioo-XPS kernel: [ 5.465863] nouveau [ DEVICE][0000:01:00.0] Family : NVE0
Jul 17 10:48:09 dioo-XPS kernel: [ 5.578886] nouveau [ VBIOS][0000:01:00.0] using image from PROM
Jul 17 10:48:09 dioo-XPS kernel: [ 5.579066] nouveau [ VBIOS][0000:01:00.0] BIT signature found
Jul 17 10:48:09 dioo-XPS kernel: [ 5.579067] nouveau [ VBIOS][0000:01:00.0] version 80.28.56.00.01
Jul 17 10:48:09 dioo-XPS kernel: [ 5.579752] nouveau [ PMC][0000:01:00.0] MSI interrupts enabled
Jul 17 10:48:09 dioo-XPS kernel: [ 5.579792] nouveau [ PFB][0000:01:00.0] RAM type: DDR3
Jul 17 10:48:09 dioo-XPS kernel: [ 5.579793] nouveau [ PFB][0000:01:00.0] RAM size: 1024 MiB
Jul 17 10:48:09 dioo-XPS kernel: [ 5.579794] nouveau [ PFB][0000:01:00.0] ZCOMP: 0 tags
Jul 17 10:48:09 dioo-XPS kernel: [ 5.581061] nouveau [ VOLT][0000:01:00.0] GPU voltage: 850000uv
Jul 17 10:48:10 dioo-XPS kernel: [ 6.879231] nouveau [ PTHERM][0000:01:00.0] FAN control: toggle
Jul 17 10:48:10 dioo-XPS kernel: [ 6.879242] nouveau [ PTHERM][0000:01:00.0] fan management: automatic
Jul 17 10:48:10 dioo-XPS kernel: [ 6.879280] nouveau [ PTHERM][0000:01:00.0] internal sensor: yes
Jul 17 10:48:10 dioo-XPS kernel: [ 6.879321] nouveau [ CLK][0000:01:00.0] 07: core 405 MHz memory 810 MHz
Jul 17 10:48:10 dioo-XPS kernel: [ 6.879354] nouveau [ CLK][0000:01:00.0] 0f: core 967 MHz memory 2002 MHz
Jul 17 10:48:10 dioo-XPS kernel: [ 6.879414] nouveau [ CLK][0000:01:00.0] --: core 405 MHz memory 810 MHz
Jul 17 10:48:10 dioo-XPS kernel: [ 6.943833] nouveau [ DRM] VRAM: 1024 MiB
Jul 17 10:48:10 dioo-XPS kernel: [ 6.943834] nouveau [ DRM] GART: 1048576 MiB
Jul 17 10:48:10 dioo-XPS kernel: [ 6.943837] nouveau [ DRM] TMDS table version 2.0
Jul 17 10:48:10 dioo-XPS kernel: [ 6.943838] nouveau [ DRM] DCB version 4.0
Jul 17 10:48:10 dioo-XPS kernel: [ 6.943839] nouveau [ DRM] DCB outp 00: 01000f02 00020030
Jul 17 10:48:10 dioo-XPS kernel: [ 6.943840] nouveau [ DRM] DCB outp 01: 02011f62 00020010
Jul 17 10:48:10 dioo-XPS kernel: [ 6.943841] nouveau [ DRM] DCB outp 02: 02022f10 00000000
Jul 17 10:48:10 dioo-XPS kernel: [ 6.943841] nouveau [ DRM] DCB conn 00: 00001031
Jul 17 10:48:10 dioo-XPS kernel: [ 6.943843] nouveau [ DRM] DCB conn 01: 00002161
Jul 17 10:48:10 dioo-XPS kernel: [ 6.943843] nouveau [ DRM] DCB conn 02: 00000200
Jul 17 10:48:10 dioo-XPS kernel: [ 6.949791] nouveau [ DRM] MM: using COPY for buffer copies
Jul 17 10:48:11 dioo-XPS kernel: [ 7.186686] nouveau [ DRM] allocated 1920x1080 fb: 0x60000, bo ffff8802128c1c00
Jul 17 10:48:11 dioo-XPS kernel: [ 7.186814] fbcon: nouveaufb (fb0) is primary devi...

[Ilia Mirkin (imirkin)]

4.0 received some additional fixes to ctxsw logic. Please try that or 4.1.

[Vhann3000+freedesktop (vhann3000+freedesktop)]

(In reply to Ilia Mirkin from comment #3)
> 4.0 received some additional fixes to ctxsw logic. Please try that or 4.1.

I compiled v4.1, but actually booted into 4.2.0-rc2 (derp), yet it didn't crash or write any error to the log files over the whole weekend.

I will keep using it and see if I can still reproduce, but right now, this appears to work for me.

I can still test v4.1 or v4.0 if you feel it would be useful.

[Vhann3000+freedesktop (vhann3000+freedesktop)]

4.2 is no go, it just locked up again.

What is interesting is that the keyboard was unresponsive (Caps Lock light didn't turn on, RESIUB wouldn't work), neither would the ACPI power off (hitting the power button), yet the computer was still responsive to the network (apache was still serving Web pages, etc). I enabled SSH so that I can log in (or try to in any case) to the computer if it happens again.

I am now testing v4.1.

[Vhann3000+freedesktop (vhann3000+freedesktop)]

v4.1.0 is no go:

Jul 20 12:55:17 dioo-XPS kernel: [ 3734.622246] usb 1-11: USB disconnect, device number 24
Jul 20 18:20:59 dioo-XPS kernel: [23270.087336] nouveau E[ PFIFO][0000:01:00.0] SCHED_ERROR [ CTXSW_TIMEOUT ]
Jul 20 18:20:59 dioo-XPS kernel: [23270.087341] nouveau E[ PFIFO][0000:01:00.0] PGRAPH engine fault on channel 2, recovering...
Jul 21 08:05:11 dioo-XPS kernel: [72704.336625] audit: type=1400 audit(1437480311.763:67): apparmor="STATUS" operation="profile_replace" name="/usr/lib/cups/backend/cups-pdf" pid=4404 comm="apparmor_parser"

I'll try v4.0 (since I don't have much to lose by doing so), but I'm guessing there won't be much difference.

[Vhann3000+freedesktop (vhann3000+freedesktop)]

One thing I did notice that I forgot to mention:

This morning, while the computer was locked up, I tried Ctrl+Alt+Delete, RESIUB then the ACPI power off and then tried to SSH into the box.

The computer turned off after several minutes which seems to indicate that the ACPI power off worked, albeit very slowly (and without updating the screen).

[Vhann3000+freedesktop (vhann3000+freedesktop)]

For anyone struggling with this bug, I haven't gotten a crash yet with Ubuntu 14.04's linux-image-3.13.0-58-generic kernel (Ubuntu version 3.13.0-58.97) over the last four days.

Maybe it'll reproduce again, but at the very this kernel version looks much more stable.

[Olivier Diotte (vhann3000)]

So far as I'm concerned, this is fixed using the Ubuntu package containing kernel 3.13.0-58-generic.

[Vhann3000+freedesktop (vhann3000+freedesktop)]

After a week's worth of usage on kernel 3.13.0, I'm confident enough to assert that that kernel version is usable.

[penalvch (penalvch)]

Olivier Diotte, thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command only once, as it will automatically gather debugging information, in a terminal:
apport-collect 1474538

[penalvch (penalvch)]

As per https://bugs.freedesktop.org/show_bug.cgi?id=91373#c10.

[JC (jcdotme)]

Distributor ID: Ubuntu
Description: Ubuntu 16.04.1 LTS
Release: 16.04
Codename: xenial
4.4.0-53-generic

My syslog and kernel.log ballooned over night to 104GB each, filling up my hard disk. I was bitten once before by this bug, but that was on the 14.04 release. Once again, I see this repeating pattern in my syslog.1 this morning:

Dec 5 17:52:05 EC-WK-35 kernel: [30894.803475] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.803492] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.803509] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.803527] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.803544] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.803561] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.803579] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.803596] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.803613] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.803630] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.803656] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.803674] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.803691] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.823012] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.823029] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.823045] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.823062] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch 2 [007f9bb000 Xorg[988]] subc 5 mthd 001c data 00000001
Dec 5 17:52:05 EC-WK-35 kernel: [30894.823078] nouveau 0000:01:00.0: fifo: PBDMA0: 04000000 [ACQUIRE] ch ...

[jay armstrong (jayarmstrong)]

same as previous poster. I've seen this once each day after installing. Kern.log and syslog baloon until drive is full. Kernel / system locks up as described in previous entries.

Ubuntu 16.04.1 running KDE Neon desktop
kernel 4.4.0-57-generic
no screensavers

[penalvch (penalvch)]

jay armstrong, as this was resolved for the original reporter, and this report is closed, it will help immensely if you filed a new report with Ubuntu, using the default repository kernel (not mainline/upstream/3rd party) via a terminal:
ubuntu-bug linux

Please feel free to subscribe me to it.

For more on why this is helpful, please see https://wiki.ubuntu.com/ReportingBugs.