Thanks for your bug report. Is this still an issue? Have you tried it in a later Ubuntu release / with a more recent version of libxcb (the report was against 1.8.1-2ubuntu2.1)?
** Changed in: libxcb (Ubuntu) Status: New => Incomplete ** Changed in: libxcb (Ubuntu) Importance: Undecided => Medium -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to libxcb in Ubuntu. https://bugs.launchpad.net/bugs/1211274 Title: xcb_wait_for_reply deadlock Status in libxcb package in Ubuntu: Incomplete Bug description: I have a Qt application which hangs in startup. Stack trace: (gdb) bt #0 0xb77b5424 in __kernel_vsyscall () #1 0xb3d2084b in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/i386-linux-gnu/libpthread.so.0 #2 0xb2a1337b in ?? () from /usr/lib/i386-linux-gnu/libxcb.so.1 #3 0xb2a14b40 in ?? () from /usr/lib/i386-linux-gnu/libxcb.so.1 #4 0xb2a14e07 in xcb_wait_for_reply () from /usr/lib/i386-linux-gnu/libxcb.so.1 #5 0xb2a3bd0b in xcb_glx_query_version_reply () from /usr/lib/i386-linux-gnu/libxcb-glx.so.0 #6 0xa08a5740 in ?? () from /usr/lib/i386-linux-gnu/qt5/plugins/platforms/libqxcb.so #7 0xa08a8b9a in ?? () from /usr/lib/i386-linux-gnu/qt5/plugins/platforms/libqxcb.so #8 0xa08aa2f9 in ?? () from /usr/lib/i386-linux-gnu/qt5/plugins/platforms/libqxcb.so #9 0xa08bb1f9 in ?? () from /usr/lib/i386-linux-gnu/qt5/plugins/platforms/libqxcb.so #10 0xb41f57f9 in ?? () from /usr/lib/i386-linux-gnu/libQt5Gui.so.5 #11 0xb41fccf4 in QGuiApplicationPrivate::createPlatformIntegration() () from /usr/lib/i386-linux-gnu/libQt5Gui.so.5 #12 0xb41fd704 in QGuiApplicationPrivate::createEventDispatcher() () from /usr/lib/i386-linux-gnu/libQt5Gui.so.5 #13 0xb482bd4b in QApplicationPrivate::createEventDispatcher() () from /usr/lib/i386-linux-gnu/libQt5Widgets.so.5 #14 0xb3f46972 in QCoreApplication::init() () from /usr/lib/i386-linux-gnu/libQt5Core.so.5 #15 0xb3f469f9 in QCoreApplication::QCoreApplication(QCoreApplicationPrivate&) () from /usr/lib/i386-linux-gnu/libQt5Core.so.5 #16 0xb41fe12a in QGuiApplication::QGuiApplication(QGuiApplicationPrivate&) () from /usr/lib/i386-linux-gnu/libQt5Gui.so.5 #17 0xb47d8de8 in QApplication::QApplication(int&, char**, int) () from /usr/lib/i386-linux-gnu/libQt5Widgets.so.5 Google shows other reports about xcb_wait_for_reply deadlocking. This happens when starting the application from .xsession file using nodm display manager. Starting the app from an x terminal works so i believe this is some kind of timing issue / race condition. The app in question is properietary so i cannot supply it to reproduce the issue, sorry. Ubuntu version is Ubuntu 13.04 x86_32 with updates installed. ProblemType: Bug DistroRelease: Ubuntu 13.04 Package: libxcb1 1.8.1-2ubuntu2.1 ProcVersionSignature: Ubuntu 3.8.0-28.41-generic 3.8.13.5 Uname: Linux 3.8.0-28-generic i686 NonfreeKernelModules: nvidia .proc.driver.nvidia.gpus.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0' .proc.driver.nvidia.registry: Binary: "" .proc.driver.nvidia.version: NVRM version: NVIDIA UNIX x86 Kernel Module 304.88 Wed Mar 27 14:31:12 PDT 2013 GCC version: gcc version 4.7.3 (Ubuntu/Linaro 4.7.3-1ubuntu1) .tmp.unity.support.test.0: ApportVersion: 2.9.2-0ubuntu8.3 Architecture: i386 CheckboxSubmission: 5411b7083f2413511daec522a712c016 CheckboxSystem: b845c366ea09c60efa3a45c1b5b21525 CompizPlugins: [core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,workarounds,scale,expo,ezoom] CompositorRunning: None Date: Mon Aug 12 14:09:50 2013 DistUpgraded: 2013-05-22 13:40:23,672 DEBUG enabling apt cron job DistroCodename: raring DistroVariant: ubuntu EcryptfsInUse: Yes GraphicsCard: NVIDIA Corporation GT216M [NVS 5100M] [10de:0a2c] (rev a2) (prog-if 00 [VGA controller]) Subsystem: Hewlett-Packard Company Device [103c:1521] InstallationDate: Installed on 2011-06-14 (790 days ago) InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1) JockeyStatus: kmod:nvidia_310_updates - NVIDIA binary Xorg driver, kernel module and VDPAU library (Proprietary, Disabled, Not in use) kmod:nvidia_313_updates - NVIDIA binary Xorg driver, kernel module and VDPAU library (Proprietary, Disabled, Not in use) kmod:nvidia_304 - nvidia_304 (Proprietary, Enabled, Not in use) kmod:nvidia_304_updates - NVIDIA binary Xorg driver, kernel module and VDPAU library (Proprietary, Disabled, Not in use) kmod:nvidia_310 - NVIDIA binary Xorg driver, kernel module and VDPAU library (Proprietary, Disabled, Not in use) MachineType: Hewlett-Packard HP EliteBook 8540p MarkForUpload: True PccardctlStatus: Socket 0: 3.3V 16-bit PC Card Subdevice 0 (function 0) bound to driver "pata_pcmcia" ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.8.0-28-generic root=UUID=debfbf8b-faee-4fef-887f-aaa61947d6d2 ro crashkernel=384M-2G:64M,2G-:128M quiet splash SourcePackage: libxcb UpgradeStatus: Upgraded to raring on 2013-05-22 (82 days ago) XorgConf: Section "Device" Identifier "Default Device" Option "NoLogo" "True" EndSection dmi.bios.date: 03/09/2011 dmi.bios.vendor: Hewlett-Packard dmi.bios.version: 68CVD Ver. F.0F dmi.board.name: 1521 dmi.board.vendor: Hewlett-Packard dmi.board.version: KBC Version 32.33 dmi.chassis.type: 10 dmi.chassis.vendor: Hewlett-Packard dmi.modalias: dmi:bvnHewlett-Packard:bvr68CVDVer.F.0F:bd03/09/2011:svnHewlett-Packard:pnHPEliteBook8540p:pvr:rvnHewlett-Packard:rn1521:rvrKBCVersion32.33:cvnHewlett-Packard:ct10:cvr: dmi.product.name: HP EliteBook 8540p dmi.sys.vendor: Hewlett-Packard version.compiz: compiz 1:0.9.9~daily13.06.19~13.04-0ubuntu1 version.libdrm2: libdrm2 2.4.43-0ubuntu1.1 version.libgl1-mesa-dri: libgl1-mesa-dri 9.1.4-0ubuntu0.1 version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A version.libgl1-mesa-glx: libgl1-mesa-glx 9.1.4-0ubuntu0.1 version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A version.xserver-xorg-core: xserver-xorg-core 2:1.13.3-0ubuntu6 version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.3-0ubuntu2b2 version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.1.0-0ubuntu2 version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.21.6-0ubuntu4.1 version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.7-0ubuntu1 xserver.bootTime: Mon Aug 12 10:00:08 2013 xserver.configfile: /etc/X11/xorg.conf xserver.errors: open /dev/dri/card0: No such file or directory open /dev/fb0: No such file or directory xserver.logfile: /var/log/Xorg.0.log xserver.outputs: xserver.version: 2:1.13.3-0ubuntu6 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libxcb/+bug/1211274/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp