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Thread: Segmentation Fault when starting Designer

  1. #1
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    Default Re: Segmentation Fault when starting Designer

    When starting the designer, I suddenly get a segmentation fault and the designer is dead.
    Console output:

    user@host:~$ designer
    QPainter::begin: Paint device returned engine == 0, type: 2
    QPainter::setFont: Painter not active
    QPainter::end: Painter not active, aborted
    QPainter::begin: Paint device returned engine == 0, type: 2
    QPainter::setFont: Painter not active
    QPainter::end: Painter not active, aborted
    QPainter::begin: Paint device returned engine == 0, type: 2
    ...
    QPainter::setPen: Painter not active
    QPainter::drawRects: Painter not active
    QPainter::restore: Unbalanced save/restore
    Gleitkomma-Ausnahme (Speicherabzug geschrieben) -> translates to segmentation fault

    Any idea what might cause Designer to crash? Qtcreator and my QT app work fine.

    System specs:
    qttools5-dev-tools - 5.12.8-0ubuntu1
    qtcreator - 4.11.0-2build2
    Ubuntu focal


    Added after 13 minutes:


    Other fun fact: I tried to install qt via the official t-unified-linux-x64-4.0.1-online.run. However, the only thing that happens is that is opens a window presumably 10000 pixels wide but without content. I have seen a similar behaviour with VLC, but could not find a solution.
    Last edited by newgen; 26th January 2021 at 18:17.

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    Default Re: Segmentation Fault when starting Designer

    apt-get update+ apt-get upgrade did not solve the problem. Designer is still broken. I am stuck with my software development.

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    Default Re: Segmentation Fault when starting Designer

    Does the Qt maintenance tool exist in the linux distribution? (Don't know - I work in Windows only now). If so, maybe give that a try? Otherwise, you might have to uninstall and reinstall Qt. Sounds like you might have a bad build, configuration, or install.
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    Default Re: Segmentation Fault when starting Designer

    Is it ubuntu 18 ? some time ago all of sudden the Qt assistant started to crash at startup, I have to start it from the command line with altered "LD_LIBRARY_PATH":
    Qt Code:
    1. LD_LIBRARY_PATH=/usr/lib/x86_64-linux-gnu assistant &
    To copy to clipboard, switch view to plain text mode 
    You might want to double check the library path on your system, I'm on windows laptop now.

    I'm not sure why it's needed but it works for me. I won't dig into that, since I'm gonna reinstall the system soon anyway. Please post here when you fix your problem.

  5. #5
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    Default Re: Segmentation Fault when starting Designer

    Thanks for the feedback and sorry for the delay.

    @d_stranz : Never heard of the maintenance tool. Will check it out. Thanks. After several "apt-get update ; apt-get upgrade" I would have assumed the qt libs to be replaced by a newer version that fix hit. However, the segmentation fault remains.

    @stampede : Double checked the path. Path looks good. However, the assistant just comes up for a second (only the window frame, no content) and also dies with segmentation fault. My system is still ubuntu focal. I will try to dig in that direction also. Though I am pessimistic as I lack the skill to debug the problem properly.

    Btw. I removed the .qt folder in my /home to exclude the possibility of a broken profile or something. No change. Open for suggestions what else to remove.


    Added after 5 minutes:


    Tried:
    apt-get --purge remove libqt5designer5* libqt5designercomponents5* libqwt-headers* libqwt-qt5-dev* qtcreator* qttools5-dev* qttools5-dev-tools*
    apt-get install libqt5designer5* libqt5designercomponents5* libqwt-headers* libqwt-qt5-dev* qtcreator* qttools5-dev* qttools5-dev-tools*
    Result:
    Segmentation fault remains.

    Tried to execute designer with root user for a change: Segmentation fault remains.


    Added after 5 minutes:


    Finally... I created a new ubuntu user and designer works. So, something in my user settings or home seems to crash the designer. Now searching the needle in the haystack.
    Last edited by newgen; 2nd March 2021 at 22:59.

  6. The following user says thank you to newgen for this useful post:

    d_stranz (2nd March 2021)

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