Hi,
```
% zbarcam-qt
QSocketNotifier: Can only be used with threads started with QThread
zsh: segmentation fault (core dumped) zbarcam-qt
```
```
PID: 348093 (zbarcam-qt)
UID: 1000 (joerg)
GID: 1000 (joerg)
Signal: 11 (SEGV)
Timestamp: Mon 2023-07-03 17:24:14 CEST (2min 36s ago)
Command Line: zbarcam-qt
Executable: /usr/bin/zbarcam-qt
Control Group: /user.slice/user-1000.slice/user@1000.service/app.slice/app-gnome-xterm-346692.scope
Unit: user@1000.service
User Unit: app-gnome-xterm-346692.scope
Slice: user-1000.slice
Owner UID: 1000 (joerg)
Boot ID: 97d7ba24ffa04374b5a1e53268047297
Machine ID: 523cb54753234ed08c13ec497d0d3b64
Hostname: zenbook
Storage: /var/lib/systemd/coredump/core.zbarcam-qt.1000.97d7ba24ffa04374b5a1e53268047297.348093.1688397854000000.zst (present)
Size on Disk: 2.2M
Message: Process 348093 (zbarcam-qt) of user 1000 dumped core.
Module libsystemd.so.0 from deb systemd-253.5-1.amd64
Stack trace of thread 348093:
#0 0x00007f7d6cee0090 XCreateGC (libX11.so.6 + 0x22090)
#1 0x00007f7d70b4300c n/a (libzbar.so.0 + 0x2f00c)
#2 0x00007f7d7141d2c4 _ZN4zbar5QZBar11changeEventEP6QEvent (libzbarqt.so.0 + 0xb2c4)
#3 0x00007f7d70da4d8f _ZN7QWidget5eventEP6QEvent (libQt5Widgets.so.5 + 0x1a4d8f)
#4 0x00007f7d70d62fae _ZN19QApplicationPrivate13notify_helperEP7QObjectP6QEvent (libQt5Widgets.so.5 + 0x162fae)
#5 0x00007f7d700b16f8 _ZN16QCoreApplication15notifyInternal2EP7QObjectP6QEvent (libQt5Core.so.5 + 0x2b16f8)
#6 0x00007f7d70da5ea8 _ZN7QWidget9setParentEPS_6QFlagsIN2Qt10WindowTypeEE (libQt5Widgets.so.5 + 0x1a5ea8)
#7 0x00007f7d70d82ba5 _ZN14QLayoutPrivate20reparentChildWidgetsEP7QWidget (libQt5Widgets.so.5 + 0x182ba5)
#8 0x00007f7d70d8e340 _ZN7QWidget9setLayoutEP7QLayout (libQt5Widgets.so.5 + 0x18e340)
#9 0x000055dbf37082db n/a (zbarcam-qt + 0x142db)
#10 0x000055dbf36ff9df n/a (zbarcam-qt + 0xb9df)
#11 0x00007f7d6f8456ca __libc_start_call_main (libc.so.6 + 0x276ca)
#12 0x00007f7d6f845785 __libc_start_main_impl (libc.so.6 + 0x27785)
#13 0x000055dbf36ffb41 n/a (zbarcam-qt + 0xbb41)
Stack trace of thread 348096:
#0 0x00007f7d6f8a3156 __futex_abstimed_wait_common64 (libc.so.6 + 0x85156)
#1 0x00007f7d6f8a5818 __pthread_cond_wait_common (libc.so.6 + 0x87818)
#2 0x00007f7d6fed1a2b _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt5Core.so.5 + 0xd1a2b)
#3 0x00007f7d6c72fc7f n/a (libQt5WaylandClient.so.5 + 0x7ac7f)
#4 0x00007f7d6fecbd43 n/a (libQt5Core.so.5 + 0xcbd43)
#5 0x00007f7d6f8a63ec start_thread (libc.so.6 + 0x883ec)
#6 0x00007f7d6f926a1c __clone3 (libc.so.6 + 0x108a1c)
Stack trace of thread 348094:
#0 0x00007f7d6f9199ef __GI___poll (libc.so.6 + 0xfb9ef)
#1 0x00007f7d6f11e9ae n/a (libglib-2.0.so.0 + 0x549ae)
#2 0x00007f7d6f11eacc g_main_context_iteration (libglib-2.0.so.0 + 0x54acc)
#3 0x00007f7d70109836 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5 + 0x309836)
#4 0x00007f7d700b017b _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5 + 0x2b017b)
#5 0x00007f7d6fecab87 _ZN7QThread4execEv (libQt5Core.so.5 + 0xcab87)
#6 0x00007f7d6ca79487 n/a (libQt5DBus.so.5 + 0x17487)
#7 0x00007f7d6fecbd43 n/a (libQt5Core.so.5 + 0xcbd43)
#8 0x00007f7d6f8a63ec start_thread (libc.so.6 + 0x883ec)
#9 0x00007f7d6f926a1c __clone3 (libc.so.6 + 0x108a1c)
Stack trace of thread 348101:
#0 0x00007f7d6f8a3156 __futex_abstimed_wait_common64 (libc.so.6 + 0x85156)
#1 0x00007f7d6f8a5818 __pthread_cond_wait_common (libc.so.6 + 0x87818)
#2 0x00007f7d5a10d989 n/a (crocus_dri.so + 0x10d989)
#3 0x00007f7d5a0c111b n/a (crocus_dri.so + 0xc111b)
#4 0x00007f7d5a10d8c7 n/a (crocus_dri.so + 0x10d8c7)
#5 0x00007f7d6f8a63ec start_thread (libc.so.6 + 0x883ec)
#6 0x00007f7d6f926a1c __clone3 (libc.so.6 + 0x108a1c)
Stack trace of thread 348098:
#0 0x00007f7d6f8a3156 __futex_abstimed_wait_common64 (libc.so.6 + 0x85156)
#1 0x00007f7d6f8a5818 __pthread_cond_wait_common (libc.so.6 + 0x87818)
#2 0x00007f7d6fed1a2b _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt5Core.so.5 + 0xd1a2b)
#3 0x00007f7d7141fc95 _ZN4zbar11QZBarThread3runEv (libzbarqt.so.0 + 0xdc95)
#4 0x00007f7d6fecbd43 n/a (libQt5Core.so.5 + 0xcbd43)
#5 0x00007f7d6f8a63ec start_thread (libc.so.6 + 0x883ec)
#6 0x00007f7d6f926a1c __clone3 (libc.so.6 + 0x108a1c)
Stack trace of thread 348097:
#0 0x00007f7d6f9199ef __GI___poll (libc.so.6 + 0xfb9ef)
#1 0x00007f7d6c72fcd6 n/a (libQt5WaylandClient.so.5 + 0x7acd6)
#2 0x00007f7d6fecbd43 n/a (libQt5Core.so.5 + 0xcbd43)
#3 0x00007f7d6f8a63ec start_thread (libc.so.6 + 0x883ec)
#4 0x00007f7d6f926a1c __clone3 (libc.so.6 + 0x108a1c)
ELF object binary architecture: AMD x86-64
[New LWP 348093]
[New LWP 348096]
[New LWP 348094]
[New LWP 348101]
[New LWP 348098]
[New LWP 348097]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `zbarcam-qt'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x00007f7d6cee0090 in XCreateGC (dpy=0x55dbf463cb30, d=9, valuemask=valuemask@entry=0, values=values@entry=0x0) at ../../src/CrGC.c:74
Download failed: Invalid argument. Continuing without source file ./build/src/../../src/CrGC.c.
74 ../../src/CrGC.c: Inappropriate ioctl for device.
[Current thread is 1 (Thread 0x7f7d6f72cd00 (LWP 348093))]
#0 0x00007f7d6cee0090 in XCreateGC (dpy=0x55dbf463cb30, d=9, valuemask=valuemask@entry=0, values=values@entry=0x0) at ../../src/CrGC.c:74
gc = <optimized out>
req = <optimized out>
ext = <optimized out>
#1 0x00007f7d70b4300c in _zbar_window_attach (w=0x55dbf469e4d0, display=<optimized out>, win=<optimized out>) at window/x.c:168
x = 0x55dbf47f3650
__PRETTY_FUNCTION__ = "_zbar_window_attach"
attr = {x = 0, y = 0, width = 0, height = 0, border_width = 0, depth = 0, visual = 0x0, root = 0, class = -981502976, bit_gravity = -951558571, win_gravity = 0, backing_store = 0, backing_planes = 18446744073709551368, backing_pixel = 0, save_under = 1819416496, colormap = 94403186311008, map_installed = -194855200, map_state = 21979, all_event_masks = 94403186779344, your_event_mask = 140176738365204, do_not_propagate_mask = 94403188176416, override_redirect = -194386736, screen = 0x55dbf463cb30}
__func__ = "_zbar_window_attach"
#2 0x00007f7d7141d2c4 in zbar::Window::attach (x11_drawable=9, x11_display_w32_hwnd=<optimized out>, this=0x55dbf469e410) at ./include/zbar/Window.h:75
No locals.
#3 zbar::QZBar::changeEvent (this=<optimized out>, event=<optimized out>) at qt/QZBar.cpp:337
locker = {val = 94403186779113}
#4 0x00007f7d70da4d8f in QWidget::event (this=0x55dbf46941d0, event=0x7ffec0d79720) at kernel/qwidget.cpp:8986
d = 0x55dbf469dc50
#5 0x00007f7d70d62fae in QApplicationPrivate::notify_helper (this=<optimized out>, receiver=0x55dbf46941d0, e=0x7ffec0d79720) at kernel/qapplication.cpp:3640
consumed = false
filtered = false
#6 0x00007f7d700b16f8 in QCoreApplication::notifyInternal2 (receiver=0x55dbf46941d0, event=0x7ffec0d79720) at kernel/qcoreapplication.cpp:1064
selfRequired = true
result = false
cbdata = {0x55dbf46941d0, 0x7ffec0d79720, 0x7ffec0d796af}
d = <optimized out>
threadData = 0x55dbf462bee0
scopeLevelCounter = {threadData = 0x55dbf462bee0}
#7 0x00007f7d700b18be in QCoreApplication::sendEvent (receiver=<optimized out>, event=<optimized out>) at kernel/qcoreapplication.cpp:1462
No locals.
#8 0x00007f7d70da5ea8 in QWidget::setParent (this=0x55dbf46941d0, parent=<optimized out>, parent@entry=0x7ffec0d79a20, f=...) at kernel/qwidget.cpp:10516
e = {_vptr.QEvent = 0x7f7d7034bb10 <vtable for QEvent+16>, static staticMetaObject = {d = {superdata = {direct = 0x0}, stringdata = 0x7f7d70278ce0 <qt_meta_stringdata_QEvent>, data = 0x7f7d70278720 <qt_meta_data_QEvent>, static_metacall = 0x0, relatedMetaObjects = 0x0, extradata = 0x0}}, d = 0x0, t = 21, posted = 0, spont = 0, m_accept = 1, reserved = 0}
d = 0x55dbf469dc50
resized = <optimized out>
wasCreated = false
oldtlw = 0x55dbf46941d0
desktopWidget = <optimized out>
newParent = <optimized out>
useStyleSheetPropagationInWidgetStyles = <optimized out>
#9 0x00007f7d70da6c78 in QWidget::setParent (parent=0x7ffec0d79a20, this=<optimized out>) at kernel/qwidget.cpp:10365
No locals.
#10 0x00007f7d70d82ba5 in QLayoutPrivate::reparentChildWidgets (this=<optimized out>, mw=mw@entry=0x7ffec0d79a20) at kernel/qlayout.cpp:841
pw = 0x0
needShow = false
w = <optimized out>
item = <optimized out>
i = 1
q = 0x55dbf470d6a0
n = 5
mwVisible = false
#11 0x00007f7d70d8e340 in QWidget::setLayout (this=this@entry=0x7ffec0d79a20, l=l@entry=0x55dbf470d6a0) at ../../include/QtWidgets/../../src/widgets/kernel/qlayout.h:64
oldParent = <optimized out>
d = 0x55dbf465d250
#12 0x000055dbf37082db in ZbarcamQZBar::ZbarcamQZBar (this=0x7ffec0d79a20, names=0x7ffec0d79a08, verbose=<optimized out>) at zbarcam/zbarcam-qt.cpp:546
videoList = 0x7f7d5c003200
statusIcon = {d = 0x55dbf4669410}
openButton = 0x55dbf4678930
optionsBoxLayout = 0x55dbf47bbd10
pos = <optimized out>
active = <optimized out>
openIcon = {d = 0x55dbf469dbc0}
grid = 0x55dbf470d6a0
button = <optimized out>
showControlsButton = 0x55dbf47b1fd0
style = <optimized out>
yesIcon = {d = 0x55dbf4664f00}
results = 0x55dbf4695eb0
showOptionsButton = <optimized out>
videoList = <optimized out>
style = <optimized out>
statusIcon = <optimized out>
yesIcon = <optimized out>
openButton = <optimized out>
openIcon = <optimized out>
results = <optimized out>
grid = <optimized out>
optionsBoxLayout = <optimized out>
pos = <optimized out>
button = <optimized out>
showOptionsButton = <optimized out>
showControlsButton = <optimized out>
active = <optimized out>
i = <optimized out>
val = <optimized out>
icon = <optimized out>
settings = <optimized out>
label = <optimized out>
button = <optimized out>
i = <optimized out>
#13 0x000055dbf36ff9df in main (argc=<optimized out>, argv=<optimized out>) at zbarcam/zbarcam-qt.cpp:1041
verbose = 0
app = {<QGuiApplication> = {<QCoreApplication> = {<QObject> = {_vptr.QObject = 0x7f7d71277ee8 <vtable for QApplication+16>, static staticMetaObject = {d = {superdata = {direct = 0x0}, stringdata = 0x7f7d7027d3e0 <qt_meta_stringdata_QObject>, data = 0x7f7d7027d2c0 <qt_meta_data_QObject>, static_metacall = 0x7f7d700e76e0 <QObject::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)>, relatedMetaObjects = 0x0, extradata = 0x0}}, d_ptr = {d = 0x55dbf462bd70}, static staticQtMetaObject = {d = {superdata = {direct = 0x0}, stringdata = 0x7f7d70280380 <qt_meta_stringdata_Qt>, data = 0x7f7d7027d500 <qt_meta_data_Qt>, static_metacall = 0x0, relatedMetaObjects = 0x0, extradata = 0x0}}}, static staticMetaObject = {d = {superdata = {direct = 0x7f7d70343140 <QObject::staticMetaObject>}, stringdata = 0x7f7d70278260 <qt_meta_stringdata_QCoreApplication>, data = 0x7f7d70278140 <qt_meta_data_QCoreApplication>, static_metacall = 0x7f7d700b2f10 <QCoreApplication::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)>, relatedMetaObjects = 0x0, extradata = 0x0}}, static self = 0x7ffec0d79a10}, static staticMetaObject = {d = {superdata = {direct = 0x7f7d7034ba60 <QCoreApplication::staticMetaObject>}, stringdata = 0x7f7d709b6740 <qt_meta_stringdata_QGuiApplication>, data = 0x7f7d709b64c0 <qt_meta_data_QGuiApplication>, static_metacall = 0x7f7d70536050 <QGuiApplication::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)>, relatedMetaObjects = 0x0, extradata = 0x0}}}, static staticMetaObject = {d = {superdata = {direct = 0x7f7d70ab30c0 <QGuiApplication::staticMetaObject>}, stringdata = 0x7f7d711138c0 <qt_meta_stringdata_QApplication>, data = 0x7f7d71113740 <qt_meta_data_QApplication>, static_metacall = 0x7f7d70d66ad0 <QApplication::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)>, relatedMetaObjects = 0x0, extradata = 0x0}}}
parser = {d = 0x55dbf465ca10}
debugOption = {d = {d = 0x55dbf465cf70}}
verboseOption = {d = {d = 0x55dbf465d150}}
args = {<QList<QString>> = {<QListSpecialMethods<QString>> = {<No data fields>}, {p = {static shared_null = {ref = {atomic = {_q_value = std::atomic<int> = { -1 }}}, alloc = 0, begin = 0, end = 0, array = {0x0}}, d = 0x7f7d70198630 <QListData::shared_null>}, d = 0x7f7d70198630 <QListData::shared_null>}}, <No data fields>}
window = {<QWidget> = {<QObject> = {_vptr.QObject = 0x55dbf370e380 <vtable for ZbarcamQZBar+16>, static staticMetaObject = {d = {superdata = {direct = 0x0}, stringdata = 0x7f7d7027d3e0 <qt_meta_stringdata_QObject>, data = 0x7f7d7027d2c0 <qt_meta_data_QObject>, static_metacall = 0x7f7d700e76e0 <QObject::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)>, relatedMetaObjects = 0x0, extradata = 0x0}}, d_ptr = {d = 0x55dbf465d250}, static staticQtMetaObject = {d = {superdata = {direct = 0x0}, stringdata = 0x7f7d70280380 <qt_meta_stringdata_Qt>, data = 0x7f7d7027d500 <qt_meta_data_Qt>, static_metacall = 0x0, relatedMetaObjects = 0x0, extradata = 0x0}}}, <QPaintDevice> = {_vptr.QPaintDevice = 0x55dbf370e530 <vtable for ZbarcamQZBar+448>, painters = 0, reserved = 0x0}, static staticMetaObject = {d = {superdata = {direct = 0x7f7d70343140 <QObject::staticMetaObject>}, stringdata = 0x7f7d71117420 <qt_meta_stringdata_QWidget>, data = 0x7f7d71116d40 <qt_meta_data_QWidget>, static_metacall = 0x7f7d70da3640 <QWidget::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)>, relatedMetaObjects = 0x0, extradata = 0x0}}, data = 0x55dbf465d370}, static staticMetaObject = {d = {superdata = {direct = 0x7f7d71279300 <QWidget::staticMetaObject>}, stringdata = 0x55dbf3709b40 <qt_meta_stringdata_ZbarcamQZBar>, data = 0x55dbf3709a20 <qt_meta_data_ZbarcamQZBar>, static_metacall = 0x55dbf3701090 <ZbarcamQZBar::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)>, relatedMetaObjects = 0x0, extradata = 0x0}}, file = {d = 0x7f7d70197b20 <QArrayData::shared_null>}, zbar = 0x55dbf46941d0, ZBarMenu = 0x55dbf469dbe0, statusButton = 0x55dbf465e150, controlGroup = 0x55dbf483ab40, optionsGroup = 0x55dbf473c240, resolutions = 0x0, controlBoxLayout = 0x55dbf483aac0, signalMapper = 0x0, dbus_enabled = false, show_options = true, show_controls = true, geometry = {d = 0x7f7d70197b20 <QArrayData::shared_null>}, res = {d = 0x7f7d70197b20 <QArrayData::shared_null>}, curWidth = 0, curHeight = 0}
--- END ---
```
Regards Jörg