Dear Maintainer,

   * What led up to the situation?

      Opening a file browser in an app (I tested two: Krita and VLC)
causes the process to reach 100% CPU usage, freezing the app. After
trying to open a file browser again, the app eventually crashes.

Steps to reproduce:

   1) Open VLC.
   2) Select "Open new file".
   3) While the file dialog popup is opening, the process reach 100% of CPU
(check with top) and VLC freeze.
   4) Close the file browser popup.
   5) Try opening a file again.
   6) This time, the app crash pass a time.


  This is part ot the coredump crash information:
-----
#5  0x00007fb06f2a15e9 in std::terminate() () from /lib/x86_64-linux-
gnu/libstdc++.so.6
#6  0x00007fb06f2b3288 in __cxa_throw () from /lib/x86_64-linux-
gnu/libstdc++.so.6
#7  0x00007fb063a91341 in qBadAlloc() () from /lib/x86_64-linux-
gnu/libQt5Core.so.5
#8  0x00007fb063a95ebd in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007fb063c4eca4 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007fb063c5191d in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#11 0x00007fb063c5ac8b in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#12 0x00007fb063c5c155 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#13 0x00007fb063c5c2fb in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#14 0x00007fb063c5c665 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#15 0x00007fb063c5ccc1 in QSettings::QSettings(QSettings::Scope, QString
const&, QString const&, QObject*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#16 0x00007fb06918bf77 in QFileDialogPrivate::restoreFromSettings() () from
/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#17 0x00007fb06918e14b in QFileDialogPrivate::init(QFileDialogArgs const&) ()
from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#18 0x00007fb06918f010 in QFileDialog::QFileDialog(QFileDialogArgs const&) ()
from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#19 0x00007fb06918f4d3 in QFileDialog::getOpenFileUrls(QWidget*, QString
const&, QUrl const&, QString const&, QString*, QFlags<QFileDialog::Option>,
QStringList const&) () from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
-----


This is the information of systemd coredump:
-----
          PID: 3490 (vlc)
           UID: 1000 (fenix)
           GID: 1000 (fenix)
        Signal: 6 (ABRT)
     Timestamp: Sun 2025-02-09 16:30:44 CET (1h 21min ago)
  Command Line: /usr/bin/vlc --started-from-file
    Executable: /usr/bin/vlc
 Control Group: /user.slice/user-1000.slice/user@1000.service/app.slice/app-
vlc@1591eddb96c640ff8e19e64122b073fa.service
          Unit: user@1000.service
     User Unit: app-vlc@1591eddb96c640ff8e19e64122b073fa.service
         Slice: user-1000.slice
     Owner UID: 1000 (fenix)
       Boot ID: 7abe9fc8f968426da238f1074e82f047
    Machine ID: 64b8d1039800478493ec6e13ee8442f9
      Hostname: Helios
       Storage:
/var/lib/systemd/coredump/core.vlc.1000.7abe9fc8f968426da238f1074e82f047.3490.1739115044000000.zst
(present)
  Size on Disk: 129.1M
       Message: Process 3490 (vlc) of user 1000 dumped core.

                Module libblkid.so.1 from deb util-linux-2.40.4-2.amd64
                Module libudev.so.1 from deb systemd-257.2-3.amd64
                Module libmount.so.1 from deb util-linux-2.40.4-2.amd64
                Module libuuid.so.1 from deb util-linux-2.40.4-2.amd64
                Module libatomic.so.1 from deb gcc-14-14.2.0-12.amd64
                Module libzstd.so.1 from deb libzstd-1.5.6+dfsg-2.amd64
                Module libarchive.so.13 from deb libarchive-3.7.4-1.1.amd64
                Module libgcc_s.so.1 from deb gcc-14-14.2.0-12.amd64
                Module libstdc++.so.6 from deb gcc-14-14.2.0-12.amd64
                Module libsystemd.so.0 from deb systemd-257.2-3.amd64
                Stack trace of thread 3494:
                #0  0x00007fb0722a9dcc n/a (libc.so.6 + 0x93dcc)
                #1  0x00007fb072255d02 raise (libc.so.6 + 0x3fd02)
                #2  0x00007fb07223e4f0 abort (libc.so.6 + 0x284f0)
                #3  0x00007fb06f2a1a3d n/a (libstdc++.so.6 + 0xa1a3d)
                #4  0x00007fb06f2b300a n/a (libstdc++.so.6 + 0xb300a)
                #5  0x00007fb06f2a15e9 _ZSt9terminatev (libstdc++.so.6 +
0xa15e9)
                #6  0x00007fb06f2b3288 __cxa_throw (libstdc++.so.6 + 0xb3288)
                #7  0x00007fb063a91341 _Z9qBadAllocv (libQt5Core.so.5 +
0x91341)
                #8  0x00007fb063a95ebd n/a (libQt5Core.so.5 + 0x95ebd)
                #9  0x00007fb063c4eca4 n/a (libQt5Core.so.5 + 0x24eca4)
                #10 0x00007fb063c5191d n/a (libQt5Core.so.5 + 0x25191d)
                #11 0x00007fb063c5ac8b n/a (libQt5Core.so.5 + 0x25ac8b)
                #12 0x00007fb063c5c155 n/a (libQt5Core.so.5 + 0x25c155)
                #13 0x00007fb063c5c2fb n/a (libQt5Core.so.5 + 0x25c2fb)
                #14 0x00007fb063c5c665 n/a (libQt5Core.so.5 + 0x25c665)
                #15 0x00007fb063c5ccc1
_ZN9QSettingsC2ENS_5ScopeERK7QStringS3_P7QObject (libQt5Core.so.5 + 0x25ccc1)
                #16 0x00007fb06918bf77
_ZN18QFileDialogPrivate19restoreFromSettingsEv (libQt5Widgets.so.5 + 0x38bf77)
                #17 0x00007fb06918e14b
_ZN18QFileDialogPrivate4initERK15QFileDialogArgs (libQt5Widgets.so.5 +
0x38e14b)
                #18 0x00007fb06918f010 _ZN11QFileDialogC1ERK15QFileDialogArgs
(libQt5Widgets.so.5 + 0x38f010)
                #19 0x00007fb06918f4d3
_ZN11QFileDialog15getOpenFileUrlsEP7QWidgetRK7QStringRK4QUrlS4_PS2_6QFlagsINS_6OptionEERK11QStringList
(libQt5Widgets.so.5 + 0x38f4d3)
                #20 0x00007fb0696bf597 n/a (libqt_plugin.so + 0xbf597)
                #21 0x00007fb0696c11d4 n/a (libqt_plugin.so + 0xc11d4)
                #22 0x00007fb0696c2123 n/a (libqt_plugin.so + 0xc2123)
                #23 0x00007fb063d185d2 n/a (libQt5Core.so.5 + 0x3185d2)
                #24 0x00007fb068f5be56 _ZN7QAction9triggeredEb
(libQt5Widgets.so.5 + 0x15be56)
                #25 0x00007fb068f5eb60 _ZN7QAction8activateENS_11ActionEventE
(libQt5Widgets.so.5 + 0x15eb60)
                #26 0x00007fb063d0b870 _ZN7QObject5eventEP6QEvent
(libQt5Core.so.5 + 0x30b870)
                #27 0x00007fb068f63052
_ZN19QApplicationPrivate13notify_helperEP7QObjectP6QEvent (libQt5Widgets.so.5 +
0x163052)
                #28 0x00007fb063cddcd8
_ZN16QCoreApplication15notifyInternal2EP7QObjectP6QEvent (libQt5Core.so.5 +
0x2ddcd8)
                #29 0x00007fb063ce11d9
_ZN23QCoreApplicationPrivate16sendPostedEventsEP7QObjectiP11QThreadData
(libQt5Core.so.5 + 0x2e11d9)
                #30 0x00007fb063d3b557 n/a (libQt5Core.so.5 + 0x33b557)
                #31 0x00007fb06810b81f n/a (libglib-2.0.so.0 + 0x5a81f)
                #32 0x00007fb06810da57 n/a (libglib-2.0.so.0 + 0x5ca57)
                #33 0x00007fb06810e1c0 g_main_context_iteration
(libglib-2.0.so.0 + 0x5d1c0)
                #34 0x00007fb063d3abed
_ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE
(libQt5Core.so.5 + 0x33abed)
                #35 0x00007fb063cdc642
_ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5 +
0x2dc642)
                #36 0x00007fb063ce5062 _ZN16QCoreApplication4execEv
(libQt5Core.so.5 + 0x2e5062)
                #37 0x00007fb0696a1595 n/a (libqt_plugin.so + 0xa1595)
                #38 0x00007fb0696a1eca n/a (libqt_plugin.so + 0xa1eca)
                #39 0x00007fb0722a8083 n/a (libc.so.6 + 0x92083)
                #40 0x00007fb0723267b8 n/a (libc.so.6 + 0x1107b8)
-----



   Thanks.

Hi Fenix!

Can you please install libqt5core5t64-dbgsym package and generate the stack
trace again? That should make it much more useful. Please see [1] for details
on how to add the debug repository, from where it can be installed.

Also, what desktop environment are you using? Do you have any of the following
packages installed?

- qt5-gtk-platformtheme
- qt5-gtk2-platformtheme
- qgnomeplatform-qt5
- qt5-xdgdesktopportal-platformtheme

[1]: https://wiki.debian.org/SourcesList#Debug_Symbol_Packages

El dom, 9 feb 2025 a las 20:56, Dmitry Shachnev (<mitya57@debian.org>) escribió:

    Hi, Dmitry.

  Sure! Sorry for the lack of information in my report.


Here is the trace with symbols in libqt5core5t64:


    KDE Plasma 6. I updated time ago from KDE Plasma 5 and apparently
without problems.
This starts to happen time after the upgrade.

   Yes.  5.15.15+dfsg-2

   No.

  No.

  No.




Thanks!

Hi again!

It looks like it crashes when trying to allocate memory for a large string:
it says len = 2147483626, which is almost 2 GB.

I found a similar issue described here [1], and the reporter solved it by
removing ~/.config/QtProject.conf file which was too large. Maybe it’s the
same in your case? Can you try to remove or move it?

If you decide to remove, maybe first look at its content and check which
field is so long, it may shed more light on this issue.

[1]: https://askubuntu.com/q/1527265

El mar, 11 feb 2025 a las 13:47, Dmitry Shachnev
(<mitya57@debian.org>) escribió:


   $ du -h QtProject.conf
530M    QtProject.conf

Wow. I think you hit the nail on the head. :)

   This is the content of QtProject.conf and the cause of the unusual size:

Hi Felix!

Thank you for the information!

I have one idea how this may happen, and it is related to using both Qt 5 and
Qt 6 applications. It looks like Qt 5 tries to backslash-escape Unicode
characters, whereas Qt 6 writes them without escaping. I filed a bug upstream
documenting that behavior: https://bugreports.qt.io/browse/QTBUG-133804.

Unfortunately, given that Qt 5 is getting end of life soon, it is unlikely
that we will see a fix in 5.15 branch. However, if you find a way to get this
bug in Qt 6 applications only, it has higher chances of getting fixed.

By the way, shortcuts are created simply by dragging directories to the left
panel.