xorg synaptic driver errors

My touchpad is behaving strangely (As far as I remember it only appeared after some update in Utopic).
Using a two or three finger click, it needs several tries till it actually "accepts" the click. Sometimes the mouse pointer jumps to a different location on the screen when clicking with two or the fingers.
Whenever the touchpad is used, errors get logged in /var/log/Xorg.0.log which seem to be related to the synaptic driver.

Approximately once every week my X server crashes with a segmentation fault. First the screen turns black and after ~30 seconds the login screen appears. In this case the Xorg.0.log ends like this:

 (EE) BUG: triggered 'if (priv->num_active_touches > priv->num_slots)'
(EE) BUG: ../../src/synaptics.c:2991 in UpdateTouchState()
(EE)
(EE) Backtrace:
(EE) 0: /usr/bin/X (xorg_backtrace+0x56) [0x7fbbab374f76]
(EE) 1: /usr/lib/xorg/modules/input/synaptics_drv.so (0x7fbba294a000+0x527e) [0x7fbba294f27e]
(EE) 2: /usr/lib/xorg/modules/input/synaptics_drv.so (0x7fbba294a000+0x75a2) [0x7fbba29515a2]
(EE) 3: /usr/bin/X (0x7fbbab1be000+0x95968) [0x7fbbab253968]
(EE) 4: /usr/bin/X (0x7fbbab1be000+0xbfff9) [0x7fbbab27dff9]
(EE) 5: /lib/x86_64-linux-gnu/libc.so.6 (0x7fbba8ef3000+0x36eb0) [0x7fbba8f29eb0]
(EE) 6: /lib/x86_64-linux-gnu/libc.so.6 (__select+0x33) [0x7fbba8fe4673]
(EE) 7: /usr/bin/X (WaitForSomething+0x1b4) [0x7fbbab372314]
(EE) 8: /usr/bin/X (0x7fbbab1be000+0x57311) [0x7fbbab215311]
(EE) 9: /usr/bin/X (0x7fbbab1be000+0x5b706) [0x7fbbab219706]
(EE) 10: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf5) [0x7fbba8f14ec5]
(EE) 11: /usr/bin/X (0x7fbbab1be000+0x45a8e) [0x7fbbab203a8e]
(EE)
(EE) [dix] SYN1B7F:01 06CB:2970 UNKNOWN: unable to find touch point 0
(EE) [dix] SYN1B7F:01 06CB:2970 UNKNOWN: unable to find touch point 0
(EE) [dix] SYN1B7F:01 06CB:2970 UNKNOWN: unable to find touch point 0
(EE) [dix] SYN1B7F:01 06CB:2970 UNKNOWN: unable to find touch point 0
(EE) [dix] SYN1B7F:01 06CB:2970 UNKNOWN: unable to find touch point 0
(EE) [dix] SYN1B7F:01 06CB:2970 UNKNOWN: unable to find touch point 0
(EE) [dix] SYN1B7F:01 06CB:2970 UNKNOWN: unable to find touch point 0
(EE) [dix] SYN1B7F:01 06CB:2970 UNKNOWN: unable to find touch point 0
[115313.777] (EE)
[115313.777] (EE) Backtrace:
[115313.778] (EE) 0: /usr/bin/X (xorg_backtrace+0x56) [0x7fbbab374f76]
[115313.779] (EE) 1: /usr/bin/X (0x7fbbab1be000+0x1bb179) [0x7fbbab379179]
[115313.779] (EE) 2: /lib/x86_64-linux-gnu/libc.so.6 (0x7fbba8ef3000+0x36eb0) [0x7fbba8f29eb0]
[115313.779] (EE) 3: /usr/bin/X (XIGetDeviceProperty+0x40) [0x7fbbab30d8a0]
[115313.779] (EE) 4: /usr/bin/X (0x7fbbab1be000+0x14f9f4) [0x7fbbab30d9f4]
[115313.779] (EE) 5: /usr/bin/X (0x7fbbab1be000+0x14ff7a) [0x7fbbab30df7a]
[115313.779] (EE) 6: /usr/bin/X (0x7fbbab1be000+0x574f7) [0x7fbbab2154f7]
[115313.779] (EE) 7: /usr/bin/X (0x7fbbab1be000+0x5b706) [0x7fbbab219706]
[115313.780] (EE) 8: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf5) [0x7fbba8f14ec5]
[115313.780] (EE) 9: /usr/bin/X (0x7fbbab1be000+0x45a8e) [0x7fbbab203a8e]
[115313.780] (EE)
[115313.782] (EE) Segmentation fault at address 0x100000018
[115313.782] (EE)
Fatal server error:
[115313.782] (EE) Caught signal 11 (Segmentation fault). Server aborting
[115313.782] (EE)
[115313.783] (EE)
Please consult the The X.Org Foundation support
         at http://wiki.x.org
 for help.
[115313.783] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[115313.783] (EE)
[115313.785] (II) AIGLX: Suspending AIGLX clients for VT switch
[115314.987] (EE) Server terminated with error (1). Closing log file.

I'm not sure if this a different bug or related to synaptic...

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: xorg 1:7.7+7ubuntu2
ProcVersionSignature: Ubuntu 3.16.0-33.44-generic 3.16.7-ckt7
Uname: Linux 3.16.0-33-generic x86_64
ApportVersion: 2.14.7-0ubuntu8.2
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: KDE
Date: Sun Mar 29 16:04:24 2015
DistUpgraded: Fresh install
DistroCodename: utopic
DistroVariant: kubuntu
DkmsStatus:
 bbswitch, 0.7, 3.16.0-33-generic, x86_64: installed
 nvidia-304, 304.125, 3.16.0-33-generic, x86_64: installed
 vboxhost, 4.3.20, 3.16.0-33-generic, x86_64: installed
EcryptfsInUse: Yes
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation Haswell-ULT Integrated Graphics Controller [8086:0a16] (rev 0b) (prog-if 00 [VGA controller])
   Subsystem: Acer Incorporated [ALI] Device [1025:091c]
InstallationDate: Installed on 2015-01-20 (68 days ago)
InstallationMedia: Kubuntu 14.10 "Utopic Unicorn" - Release amd64 (20141022.1)
LightdmGreeterLog:
 QInotifyFileSystemWatcherEngine::addPaths: inotify_add_watch failed: Datei oder Verzeichnis nicht gefunden
 QFileSystemWatcher: failed to add paths: /var/lib/lightdm/.config/ibus/bus
 Bus::open: Can not get ibus-daemon's address.
 IBusInputContext::createInputContext: no connection to ibus-daemon
LightdmGreeterLogOld:
 QInotifyFileSystemWatcherEngine::addPaths: inotify_add_watch failed: Datei oder Verzeichnis nicht gefunden
 QFileSystemWatcher: failed to add paths: /var/lib/lightdm/.config/ibus/bus
 Bus::open: Can not get ibus-daemon's address.
 IBusInputContext::createInputContext: no connection to ibus-daemon
MachineType: Acer Aspire VN7-571G
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.16.0-33-generic root=UUID=5ebd3c26-8bee-44ee-a832-0dbfb0ee72f4 ro quiet splash
SourcePackage: xorg
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/12/2014
dmi.bios.vendor: Insyde Corp.
dmi.bios.version: V1.08
dmi.board.asset.tag: No Asset Tag
dmi.board.name: Aspire VN7-571G
dmi.board.vendor: Acer
dmi.board.version: V1.08
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: V1.08
dmi.modalias: dmi:bvnInsydeCorp.:bvrV1.08:bd09/12/2014:svnAcer:pnAspireVN7-571G:pvrV1.08:rvnAcer:rnAspireVN7-571G:rvrV1.08:cvnAcer:ct10:cvrV1.08:
dmi.product.name: Aspire VN7-571G
dmi.product.version: V1.08
dmi.sys.vendor: Acer
version.compiz: compiz N/A
version.ia32-libs: ia32-libs 20090808ubuntu36
version.libdrm2: libdrm2 2.4.56-1
version.libgl1-mesa-dri: libgl1-mesa-dri 10.3.2-0ubuntu0.1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 10.3.2-0ubuntu0.1
version.xserver-xorg-core: xserver-xorg-core 2:1.16.0-1ubuntu1.3
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.9.0-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.4.0-2ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.914-1~exp1ubuntu4.2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.11-1ubuntu2
xserver.bootTime: Sat Mar 28 13:16:00 2015
xserver.configfile: default
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:
 product id 1091
 vendor LGD
xserver.version: 2:1.16.0-1ubuntu1.3