compiz assert failure: compiz: ../../nouveau/pushbuf.c:238: pushbuf_krel: Assertion `bkref' failed.

This crash happens a few times per day when I'm using my PC. I've noticed that it seems to be triggered when I use Alt-Tab to switch between applications.

The whole Unity desktop seems to freeze for a few seconds, then everything is redrawn, presumably because Unity automatically restarts.

ProblemType: Crash
DistroRelease: Ubuntu 16.04
Package: compiz-core 1:0.9.12.2+16.04.20160801.3-0ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-34.53-generic 4.4.15
Uname: Linux 4.4.0-34-generic x86_64
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
AssertionMessage: compiz: ../../nouveau/pushbuf.c:238: pushbuf_krel: Assertion `bkref' failed.
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CrashCounter: 1
CurrentDesktop: Unity
Date: Mon Aug 22 12:34:10 2016
DistUpgraded: Fresh install
DistroCodename: xenial
DistroVariant: ubuntu
ExecutablePath: /usr/bin/compiz
GraphicsCard: NVIDIA Corporation G73 [GeForce 7600 GS] [10de:02e1] (rev a2) (prog-if 00 [VGA controller])
InstallationDate: Installed on 2016-07-06 (47 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
LightdmDisplayLog: resize called 1280 1024
ProcCmdline: compiz
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-34-generic root=UUID=0f987da0-2c98-45bb-8f25-38817aa06196 ro quiet splash vt.handoff=7
Signal: 6
SourcePackage: compiz
StacktraceTop:
 __assert_fail_base (fmt=<optimised out>, assertion=assertion@entry=0x7f202eaa1728 "bkref", file=file@entry=0x7f202eaa170a "../../nouveau/pushbuf.c", line=line@entry=238, function=function@entry=0x7f202eaa1768 "pushbuf_krel") at assert.c:92
 __GI___assert_fail (assertion=0x7f202eaa1728 "bkref", file=0x7f202eaa170a "../../nouveau/pushbuf.c", line=238, function=0x7f202eaa1768 "pushbuf_krel") at assert.c:101
 ?? () from /usr/lib/x86_64-linux-gnu/libdrm_nouveau.so.2
 nouveau_pushbuf_reloc () from /usr/lib/x86_64-linux-gnu/libdrm_nouveau.so.2
 ?? () from /usr/lib/x86_64-linux-gnu/dri/nouveau_dri.so
Title: compiz assert failure: compiz: ../../nouveau/pushbuf.c:238: pushbuf_krel: Assertion `bkref' failed.
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
dmi.bios.date: 07/10/2006
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P2.30
dmi.board.asset.tag: 00000000
dmi.board.name: K8Upgrade-VM800
dmi.board.version: 1.00
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP2.30:bd07/10/2006:svn:pnK8Upgrade-VM800:pvr1.00:rvn:rnK8Upgrade-VM800:rvr1.00:
dmi.product.name: K8Upgrade-VM800
dmi.product.version: 1.00
version.compiz: compiz 1:0.9.12.2+16.04.20160801.3-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.67-1ubuntu0.16.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 11.2.0-1ubuntu2.1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.2.0-1ubuntu2.1
version.xserver-xorg-core: xserver-xorg-core 2:1.18.3-1ubuntu2.3
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati N/A
version.xserver-xorg-video-intel: xserver-xorg-video-intel N/A
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-1build2
xserver.bootTime: Mon Aug 22 10:49:44 2016
xserver.configfile: default
xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.18.3-1ubuntu2.3
xserver.video_driver: nouveau