unity8 crashed with SIGSEGV in XGetXCBConnection()

[Yulian]

Just tryed to login after kernel update. Did not get to the login screen

ProblemType: Crash
DistroRelease: Ubuntu 16.04
Package: unity8 8.11+16.04.20160129-0ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-2.16-generic 4.4.0
Uname: Linux 4.4.0-2-generic x86_64
ApportVersion: 2.19.4-0ubuntu2
Architecture: amd64
Date: Fri Feb 5 04:24:17 2016
EcryptfsInUse: Yes
ExecutablePath: /usr/bin/unity8
ProcCmdline: unity8
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x7f6b30e586e7 <XGetXCBConnection+7>: mov (%rax),%rax
 PC (0x7f6b30e586e7) ok
 source "(%rax)" (0x00000000) not located in a known VMA region (needed readable region)!
 destination "%rax" ok
 Stack memory exhausted (SP below stack segment)
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: unity8
StacktraceTop:
 XGetXCBConnection () from /usr/lib/x86_64-linux-gnu/libX11-xcb.so.1
 ?? () from /usr/lib/x86_64-linux-gnu/mesa-egl/libEGL.so.1
 ?? () from /usr/lib/x86_64-linux-gnu/mesa-egl/libEGL.so.1
 ?? () from /usr/lib/x86_64-linux-gnu/mesa-egl/libEGL.so.1
 eglInitialize () from /usr/lib/x86_64-linux-gnu/mesa-egl/libEGL.so.1
Title: unity8 crashed with SIGSEGV in XGetXCBConnection()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
upstart.unity8-filewatcher.log:

[Albert Astals Cid (aacid)]

XGetXCBConnect means it's trying to use X11 instead of Mir.

That should not happen.

I understand you're using xenial, right?

Can you attach the output of this command?
  dpkg -l | grep mir

[Yulian (yu-kalev)]

ii libmirclient9:amd64 0.19.1+16.04.20160204-0ubuntu1 amd64 Display server for Ubuntu - client library
ii libmircommon5:amd64 0.19.1+16.04.20160204-0ubuntu1 amd64 Display server for Ubuntu - shared library
ii libmircookie2:amd64 0.19.1+16.04.20160204-0ubuntu1 amd64 Produce and verify spoof-resistant timestamps - runtime library
ii libmirplatform11:amd64 0.19.1+16.04.20160204-0ubuntu1 amd64 Display server for Ubuntu - platform library
ii libmirprotobuf3:amd64 0.19.1+16.04.20160204-0ubuntu1 amd64 Display server for Ubuntu - RPC definitions
ii libmirserver37:amd64 0.19.1+16.04.20160204-0ubuntu1 amd64 Display server for Ubuntu - server library
ii mir-client-platform-mesa4:amd64 0.19.1+16.04.20160204-0ubuntu1 amd64 Display server for Ubuntu - client platform library for Mesa
ii mir-graphics-drivers-desktop:amd64 0.19.1+16.04.20160204-0ubuntu1 amd64 Display server for Ubuntu - desktop driver metapackage
ii mir-platform-graphics-mesa-kms7:amd64 0.19.1+16.04.20160204-0ubuntu1 amd64 Display server for Ubuntu - platform library for KMS Mesa
ii mir-platform-graphics-mesa-x7:amd64 0.19.1+16.04.20160204-0ubuntu1 amd64 Display server for Ubuntu - platform library for X11 Mesa
ii mir-platform-input-evdev5:amd64 0.19.1+16.04.20160204-0ubuntu1 amd64 Display server for Ubuntu - input platform library
ii qtdeclarative5-qtmir-plugin:amd64 0.4.7+16.04.20160127.1-0ubuntu1 amd64 Qt plugin for Unity specific Mir APIs
ii qtmir-desktop:amd64 0.4.7+16.04.20160127.1-0ubuntu1 amd64 Qt platform abstraction (QPA) plugin for a Mir server (desktop)
ii unity8-desktop-session-mir 1.0.12+15.10.20150609-0ubuntu1 all Unity8 desktop session for Mir

[Albert Astals Cid (aacid)]

That looks good, what are you using to login into untiy8, is it regular lightdm or some other display manager?

[Yulian (yu-kalev)]

lightdm. ive done to it nothing but the standard install

[Yulian (yu-kalev)]

just did

aptitude purge unity8-desktop-session-mir

(reboot)

apt-get install unity8-desktop-session-mir

(reboot)

and got the same result as he https://bugs.launchpad.net/ubuntu/+source/unity8/+bug/1543133 (possible dubl.?)

[Apport retracing service (apport)]

StacktraceSource:
 #0 0x00007f6b30e586e7 in XGetXCBConnection (dpy=0x7f6b10001620) at ../../src/x11_xcb.c:9
   [Error: x11_xcb.c was not found in source tree]
 #1 0x00007f6b2cf43694 in swrast_update_buffers () from /tmp/apport_sandbox_AivIfB/usr/lib/x86_64-linux-gnu/mesa-egl/libEGL.so.1
 #2 0x0000000000000000 in ?? ()
StacktraceTop:
 XGetXCBConnection (dpy=0x7f6b10001620) at ../../src/x11_xcb.c:9
 swrast_update_buffers () from /tmp/apport_sandbox_AivIfB/usr/lib/x86_64-linux-gnu/mesa-egl/libEGL.so.1
 ?? ()

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Albert Astals Cid (aacid)]

Adding the mir guys in case they can help.

Mir people should we be using mesa here at all? And if so any idea why mesa would be calling XGetXCBConnection ?

[kevin gunn (kgunn72)]

yes - if this is unity8 on desktop session, it's using mesa not android. but not sure why x11 would be involved? when running unity8-desktop-session-mir directly on the drivers, not xmir.

also, there was a transition seeding issue discovered on the desktop, where you needed to $ sudo apt-get remove mir-client-platform-mesa3 mir-client-platform-mesa2 mir-client-platform-mesa1 in order to make sure mir picks up the correct platform. might make sure to do that.

[Daniel van Vugt (vanvugt)]

Try upgrading your system.

Although we declared bug 1526658 fixed in Mir 0.19.0, that did not feature a retrospective fix for those already affected. You need Mir 0.20 or later for the full fix.