Xorg crash with Trident driver after Xubuntu upgrade to Trusty

[Dirk F]

After upgrading Xubuntu 12.04 LTS -> 14.04.1 LTS, system boots to black screen instead of desktop environment, but single user command line works fine. Problem traced to xorg-server segfault crash in the Trident driver as below (summary of details already uploaded). The code attempts a call to an offset against eax which is a null pointer.

After changing the acceleration architecture from XAA to EXA with
    Option "AccelMethod" "exa"
in the Trident Device section of xorg.conf, the desktop environment loaded successfully.

Maybe this option should now be the default for Trident?

ProblemType: Crash
Architecture: i386
CrashCounter: 1
Date: Tue Sep 9 13:26:36 2014
DistroRelease: Ubuntu 14.04
ExecutablePath: /usr/bin/Xorg
ExecutableTimestamp: 1406679727
ProcCmdline: /usr/bin/X -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nol
isten tcp vt7 -novtswitch
ProcCwd: /etc/X11
ProcEnviron:

Disassembly:
 => 0xb6cb39d1: call *0x6c(%eax)
    0xb6cb39d4: jmp 0xb6cb3979
    0xb6cb39d6: lea 0x0(%esi),%esi
    0xb6cb39d9: lea 0x0(%edi,%eiz,1),%edi
    0xb6cb39e0: push %ebp
    0xb6cb39e1: mov %eax,%ebp
    0xb6cb39e3: push %edi
    0xb6cb39e4: xor %edi,%edi
    0xb6cb39e6: push %esi
    0xb6cb39e7: mov $0x20000,%esi
    0xb6cb39ec: push %ebx
    0xb6cb39ed: sub $0x1c,%esp
    0xb6cb39f0: mov 0x18(%eax),%eax
    0xb6cb39f3: call 0xb6caa4f0
    0xb6cb39f8: add $0x14608,%ebx
    0xb6cb39fe: sub $0x17,%eax
Package: xserver-xorg-core 2:1.15.1-0ubuntu2.1
PackageArchitecture: i386
ProcVersionSignature: Ubuntu 3.13.0-36.63-generic 3.13.11.6
Registers:
 eax 0x0 0
 ecx 0x0 0
 edx 0xb96d7cb0 -1184006992
 ebx 0xb6cc8000 -1228111872
 esp 0xbf887300 0xbf887300
 ebp 0xb96d5688 0xb96d5688
 esi 0xb96d3f98 -1184022632
 edi 0xb96d43f8 -1184021512
 eip 0xb6cb39d1 0xb6cb39d1
 eflags 0x213202 [ IF #12 #13 RF ID ]
 cs 0x73 115
 ss 0x7b 123
 ds 0x7b 123
 es 0x7b 123
 fs 0x0 0
 gs 0x33 51
SegvAnalysis:
 Segfault happened at: 0xb6cb39d1: call *0x6c(%eax)
 PC (0xb6cb39d1) ok
 source "*0x6c(%eax)" ok
 destination "(%esp)" (0xbf887300) ok
 SP (0xbf887300) ok
 Reason could not be automatically determined.
SourcePackage: xorg-server
...
Title: Xorg crashed with SIGSEGV in xf86VTSwitch()
UpgradeStatus: Upgraded to trusty on 2014-09-07 (2 days ago)
_MarkForUpload: True

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: xorg 1:7.7+1ubuntu8
ProcVersionSignature: Ubuntu 3.13.0-36.63-generic 3.13.11.6
Uname: Linux 3.13.0-36-generic i686
ApportVersion: 2.14.1-0ubuntu3.4
Architecture: i386
CurrentDesktop: XFCE
Date: Tue Sep 9 18:09:01 2014
SourcePackage: xorg
UpgradeStatus: Upgraded to trusty on 2014-09-07 (2 days ago)

[Dirk F (fieldhouse)]

Whereas in 10.10, the reverse problem occurred (bug 209018): XAA worked and EXA crashed.

[Paul White (paulw2u)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. We are sorry that we do not always have the capacity to review all reported bugs in a timely manner.

Ubuntu 14.04 (trusty) reached end-of-standard-support on April 25, 2019.

I'm setting the status of this bug to 'Incomplete' as it's not seen any activity for some time. If this bug report has any relevance when using a currently maintained release of Ubuntu then please let us know which one(s) otherwise this bug report can be left to expire in approximately 60 days time.

[Launchpad Janitor (janitor)]

[Expired for xorg (Ubuntu) because there has been no activity for 60 days.]