Bugzilla – Bug 911304
XCB: QApplication crashes with no monitor or in multimonitor setups
Last modified: 2016-07-12 19:51:22 UTC
User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:34.0) Gecko/20100101 Firefox/34.0 Build Identifier: yast2 segfaults when monitor (lcd tv over hdmi) is switched off, and yast2 is started remotely via teamviewer. If the monitor is on, yast2 starts up successfully. (The system is accessed via teamviewer) dmesg shows: [ 3971.461373] y2controlcenter[3822]: segfault at 18 ip 00007fe36f5c40fc sp 00007fff39168120 error 4 in libqxcb.so[7fe36f57e000+b0000] Reproducible: Always Steps to Reproduce: 1.have an opensuse 13.2 system with teamviewer installed (other remote desktop products not confirmed) 2.switch off monitor 3.log on to the opensuse box via teamviewer, try to start yast2 (control center) Actual Results: segfault: dmesg shows: [ 3971.461373] y2controlcenter[3822]: segfault at 18 ip 00007fe36f5c40fc sp 00007fff39168120 error 4 in libqxcb.so[7fe36f57e000+b0000] Expected Results: yast2 starts up successfully This may be an error in the Qt library, in which case the bug should be handled by the Qt team... dmesg shows: [ 3971.461373] y2controlcenter[3822]: segfault at 18 ip 00007fe36f5c40fc sp 00007fff39168120 error 4 in libqxcb.so[7fe36f57e000+b0000]
Please attach all Yast logs: https://en.opensuse.org/openSUSE:Report_a_YaST_bug
Created attachment 618567 [details] yast2 logs and commands executed Commands executed before: (because yast2 seems to be segfaulting before it can log anything, according to file dates) htpc:/home/balint # dmesg -c htpc:/home/balint # ls -la /var/log/YaST2/ total 4228 drwx------ 2 root root 4096 Jan 2 16:10 . drwxr-xr-x 12 root root 4096 Jan 2 16:13 .. -rw-r--r-- 1 root root 59 Dec 22 18:16 arch.info -rw-r--r-- 1 root root 1924 Dec 22 18:06 config_diff_2014_12_22.log -rw-r--r-- 1 root root 645 Dec 22 18:16 curl_log -rw-r--r-- 1 root root 512 Dec 22 18:15 _dev_sda -rw-r--r-- 1 root root 512 Dec 22 18:15 _dev_sda4 -rw-r--r-- 1 root root 2749 Dec 22 18:16 disk_sda.info -rw-r--r-- 1 root root 1559 Dec 22 18:16 disk_sdb.info -rw-r--r-- 1 root root 30 Dec 22 18:16 free.info -rw-r--r-- 1 root root 47273 Dec 22 18:16 macro_inst_initial.ycp -rw-r--r-- 1 root root 10296 Dec 22 18:15 mkinitrd.log -rw-r--r-- 1 root root 9102 Dec 22 18:16 pbl-instsys.log -rw-r--r-- 1 root root 18331 Dec 22 18:15 perl-BL-standalone-log -rw------- 1 root root 1800 Jan 2 16:10 signal -rw-r--r-- 1 root root 210 Dec 22 18:16 sntp.log -rw-r--r-- 1 root root 4461 Dec 22 18:16 y2changes -rw-r--r-- 1 root root 2978051 Jan 2 16:10 y2log -rw-r--r-- 1 root root 1180917 Dec 22 18:16 y2log-1.gz -rw-r--r-- 1 root root 1559 Dec 22 18:15 y2logmkinitrd -rw-r--r-- 1 root root 3315 Dec 22 18:16 y2start.log htpc:/home/balint # date Fri Jan 2 16:15:27 CET 2015 htpc:/home/balint # Y2DEBUG=1 yast2 /sbin/yast2: line 440: 1531 Segmentation fault $y2ccbin $Y2UI_ARGS "$@" htpc:/home/balint # dmesg -c [ 127.390014] y2controlcenter[1531]: segfault at 18 ip 00007f159dc500fc sp 00007fffef9b1250 error 4 in libqxcb.so[7f159dc0a000+b0000] htpc:/home/balint # date Fri Jan 2 16:15:57 CET 2015 htpc:/home/balint # ls -la /var/log/YaST2/ total 4228 drwx------ 2 root root 4096 Jan 2 16:10 . drwxr-xr-x 12 root root 4096 Jan 2 16:13 .. -rw-r--r-- 1 root root 59 Dec 22 18:16 arch.info -rw-r--r-- 1 root root 1924 Dec 22 18:06 config_diff_2014_12_22.log -rw-r--r-- 1 root root 645 Dec 22 18:16 curl_log -rw-r--r-- 1 root root 512 Dec 22 18:15 _dev_sda -rw-r--r-- 1 root root 512 Dec 22 18:15 _dev_sda4 -rw-r--r-- 1 root root 2749 Dec 22 18:16 disk_sda.info -rw-r--r-- 1 root root 1559 Dec 22 18:16 disk_sdb.info -rw-r--r-- 1 root root 30 Dec 22 18:16 free.info -rw-r--r-- 1 root root 47273 Dec 22 18:16 macro_inst_initial.ycp -rw-r--r-- 1 root root 10296 Dec 22 18:15 mkinitrd.log -rw-r--r-- 1 root root 9102 Dec 22 18:16 pbl-instsys.log -rw-r--r-- 1 root root 18331 Dec 22 18:15 perl-BL-standalone-log -rw------- 1 root root 1800 Jan 2 16:10 signal -rw-r--r-- 1 root root 210 Dec 22 18:16 sntp.log -rw-r--r-- 1 root root 4461 Dec 22 18:16 y2changes -rw-r--r-- 1 root root 2978051 Jan 2 16:10 y2log -rw-r--r-- 1 root root 1180917 Dec 22 18:16 y2log-1.gz -rw-r--r-- 1 root root 1559 Dec 22 18:15 y2logmkinitrd -rw-r--r-- 1 root root 3315 Dec 22 18:16 y2start.log htpc:/home/balint # Y2DEBUGALL=1 yast2 /sbin/yast2: line 440: 1567 Segmentation fault $y2ccbin $Y2UI_ARGS "$@" htpc:/home/balint # dmesg -c [ 188.266418] y2controlcenter[1567]: segfault at 18 ip 00007fb6cac720fc sp 00007fff55d81bd0 error 4 in libqxcb.so[7fb6cac2c000+b0000] htpc:/home/balint # ls -la /var/log/YaST2/ total 4228 drwx------ 2 root root 4096 Jan 2 16:10 . drwxr-xr-x 12 root root 4096 Jan 2 16:13 .. -rw-r--r-- 1 root root 59 Dec 22 18:16 arch.info -rw-r--r-- 1 root root 1924 Dec 22 18:06 config_diff_2014_12_22.log -rw-r--r-- 1 root root 645 Dec 22 18:16 curl_log -rw-r--r-- 1 root root 512 Dec 22 18:15 _dev_sda -rw-r--r-- 1 root root 512 Dec 22 18:15 _dev_sda4 -rw-r--r-- 1 root root 2749 Dec 22 18:16 disk_sda.info -rw-r--r-- 1 root root 1559 Dec 22 18:16 disk_sdb.info -rw-r--r-- 1 root root 30 Dec 22 18:16 free.info -rw-r--r-- 1 root root 47273 Dec 22 18:16 macro_inst_initial.ycp -rw-r--r-- 1 root root 10296 Dec 22 18:15 mkinitrd.log -rw-r--r-- 1 root root 9102 Dec 22 18:16 pbl-instsys.log -rw-r--r-- 1 root root 18331 Dec 22 18:15 perl-BL-standalone-log -rw------- 1 root root 1800 Jan 2 16:10 signal -rw-r--r-- 1 root root 210 Dec 22 18:16 sntp.log -rw-r--r-- 1 root root 4461 Dec 22 18:16 y2changes -rw-r--r-- 1 root root 2978051 Jan 2 16:10 y2log -rw-r--r-- 1 root root 1180917 Dec 22 18:16 y2log-1.gz -rw-r--r-- 1 root root 1559 Dec 22 18:15 y2logmkinitrd -rw-r--r-- 1 root root 3315 Dec 22 18:16 y2start.log htpc:/home/balint # tar -czf logs.tar.gz /var/lo lock/ log/ htpc:/home/balint # tar -czf logs.tar.gz /var/lo lock/ log/ htpc:/home/balint # tar -czf logs.tar.gz /var/log/YaST2/* tar: Removing leading `/' from member names htpc:/home/balint #
It looks like a problem in Qt (segfaults in libqxcb.so), but I'm not an libyui-qt expert, Martin, please check...
Thanks for the report, Bálint. We will need a better backtrace: 1. please install libQt5Core5-debuginfo libQt5Gui5-debuginfo libQt5Widgets5-debuginfo 2. enable dumping of core files: ulimit -c unlimited 3. run YaST and let it segfault 4. get the backtrace gdb /usr/lib/YaST2/bin/y2base core (gdb) thread apply all bt I am reassigning to KDE maintainers as this seems to be a Qt5 bug. Past bugs related to QXCB: bug 883553, bug 890168.
This seems to be a known issue in Qt5: http://qt-project.org/forums/viewthread/28101 https://bugreports.qt.io/browse/QTBUG-31354
*** Bug 917054 has been marked as a duplicate of this bug. ***
*** Bug 949978 has been marked as a duplicate of this bug. ***
*** Bug 954434 has been marked as a duplicate of this bug. ***
*** Bug 954538 has been marked as a duplicate of this bug. ***
Lets update this so it is obvious it happens with all qt5 based systems regardless it being leap/tw/13.2. Also it seems since so many ppl noticed we should probably raise serverity.
*** Bug 937100 has been marked as a duplicate of this bug. ***
It seems this bug has been fixed upstream: https://bugreports.qt.io/browse/QTBUG-42985 So how does a next step look like? I am clearing needinfo by pbalint@gmail.com as it seems all necessary info is there :-)
Hi! So repro steps: -Install an OpenSUSE box with GUI (tested with KDE) -Install teamviewer onto machine above(https://www.teamviewer.com/en/download/windows.aspx) -Make the machine headless (*unplug* all vga/hdmi/dvi/displayport/etc cables) -On a different machine, also install teamviwer, and log onto the openSUSE box above -Run Qt5 application, e.g. YaST2 with Qt GUI Other repro (may/may not repro the issue) -Do all of the above, but instead of teamviwer, use VNC Basically, the root of the issue is that Qt5 applications fail to start, when there is no physical display attached *at all*. (e.g. cable not attached, or attached, but powered off. Sleep/power saving mode on the display does not count, as it still seems to provide some info to the graphics adapter)
Direct teamviewer link for linux: http://download.teamviewer.com/download/teamviewer.i686.rpm
Oh, misread "clearing needinfo" to "clearly needinfo"... My bad... :-)
as per previous comments