Details
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Bug
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Resolution: Fixed
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P1: Critical
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5.15.13
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None
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Linux/Wayland
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689957dec (tqtc/lts-5.15)
Description
In our application we use a custom VNC server (libvncserver) and send generated key-events via qApp->postEvent().
In some cases we see a crash, when a key with modifier "Control" was pressed.
This was seen in Qt 5.15.13, but the source qxkbcommon.cpp seems to be similar in Qt6.
xkb_state_get_keymap in this callstack is called with state = nullptr, leading to SEGV
(as a simple solution, state should be checked to be != nullptr, before calling this,
in qxkbcommon.cpp Line 757 and probably also L 522)
Callstack for Qt 5.15.13:
Thread 1 "addressbook" received signal SIGSEGV, Segmentation fault. 0x00007fd470b8d0d4 in xkb_state_get_keymap () from /lib/x86_64-linux-gnu/libxkbcommon.so.0 (gdb) bt #0 0x00007fd470b8d0d4 in xkb_state_get_keymap () from /lib/x86_64-linux-gnu/libxkbcommon.so.0 #1 0x00007fd46e7645a0 in QXkbCommon::lookupLatinKeysym (state=0x0, keycode=0) at /home/haufler/git/qt5.15.13/qt5/qtbase/src/platformsupport/input/xkbcommon/qxkbcommon.cpp:757 #2 0x00007fd46e763725 in QXkbCommon::keysymToQtKey (keysym=16777315, modifiers=..., state=0x0, code=0, superAsMeta=false, hyperAsMeta=false) at /home/haufler/git/qt5.15.13/qt5/qtbase/src/platformsupport/input/xkbcommon/qxkbcommon.cpp:527 #3 0x00007fd46e7636a1 in QXkbCommon::keysymToQtKey (keysym=16777315, modifiers=...) at /home/haufler/git/qt5.15.13/qt5/qtbase/src/platformsupport/input/xkbcommon/qxkbcommon.cpp:507 #4 0x00007fd46e6f29b8 in QtWaylandClient::QWaylandTextInput::zwp_text_input_v2_keysym (this=0x55ff3ed294b0, time=0, sym=16777315, state=1, modifiers=2) at /home/haufler/git/qt5.15.13/qt5/qtwayland/src/client/qwaylandinputcontext.cpp:340 #5 0x00007fd46e70d617 in QtWayland::zwp_text_input_v2::handle_keysym (data=0x55ff3ed294b0, object=0x55ff3ed3eba0, time=0, sym=16777315, state=1, modifiers=2) at qwayland-text-input-unstable-v2.cpp:323 #6 0x00007fd470b69e2e in ?? () from /lib/x86_64-linux-gnu/libffi.so.8 #7 0x00007fd470b66493 in ?? () from /lib/x86_64-linux-gnu/libffi.so.8 #8 0x00007fd471621ad0 in ?? () from /lib/x86_64-linux-gnu/libwayland-client.so.0 #9 0x00007fd471622243 in ?? () from /lib/x86_64-linux-gnu/libwayland-client.so.0 #10 0x00007fd47162243c in wl_display_dispatch_queue_pending () from /lib/x86_64-linux-gnu/libwayland-client.so.0 #11 0x00007fd46e6cf946 in QtWaylandClient::QWaylandDisplay::flushRequests (this=0x55ff3ed2cf10) at /home/haufler/git/qt5.15.13/qt5/qtwayland/src/client/qwaylanddisplay.cpp:224 #12 0x00007fd46e6d2302 in QtWaylandClient::QWaylandDisplay::qt_static_metacall (_o=0x55ff3ed2cf10, _c=QMetaObject::InvokeMetaMethod, _id=1, _a=0x7ffc44860860) at .moc/moc_qwaylanddisplay_p.cpp:77 #13 0x00007fd4723c851a in doActivate<false> (sender=0x55ff3ed4e430, signal_index=3, argv=0x7ffc44860860) at /home/haufler/git/qt5.15.13/qt5/qtbase/src/corelib/kernel/qobject.cpp:3937 #14 0x00007fd4723c1273 in QMetaObject::activate (sender=0x55ff3ed4e430, m=0x7fd47279a3e0 <QSocketNotifier::staticMetaObject>, local_signal_index=0, argv=0x7ffc44860860) at /home/haufler/git/qt5.15.13/qt5/qtbase/src/corelib/kernel/qobject.cpp:3985 #15 0x00007fd4723d2c9e in QSocketNotifier::activated (this=0x55ff3ed4e430, _t1=..., _t2=QSocketNotifier::Read, _t3=...) at .moc/moc_qsocketnotifier.cpp:178 #16 0x00007fd4723d27ce in QSocketNotifier::event (this=0x55ff3ed4e430, e=0x7ffc44860de0) at /home/haufler/git/qt5.15.13/qt5/qtbase/src/corelib/kernel/qsocketnotifier.cpp:302 #17 0x00007fd472991821 in QApplicationPrivate::notify_helper (this=0x55ff3ed241e0, receiver=0x55ff3ed4e430, e=0x7ffc44860de0) at /home/haufler/git/qt5.15.13/qt5/qtbase/src/widgets/kernel/qapplication.cpp:3652 #18 0x00007fd47298e9d7 in QApplication::notify (this=0x7ffc44862770, receiver=0x55ff3ed4e430, e=0x7ffc44860de0) at /home/haufler/git/qt5.15.13/qt5/qtbase/src/widgets/kernel/qapplication.cpp:2984 #19 0x00007fd47236f457 in QCoreApplication::notifyInternal2 (receiver=0x55ff3ed4e430, event=0x7ffc44860de0) at /home/haufler/git/qt5.15.13/qt5/qtbase/src/corelib/kernel/qcoreapplication.cpp:1064 #20 0x00007fd47236ff1c in QCoreApplication::sendEvent (receiver=0x55ff3ed4e430, event=0x7ffc44860de0) at /home/haufler/git/qt5.15.13/qt5/qtbase/src/corelib/kernel/qcoreapplication.cpp:1462 #21 0x00007fd47240e129 in socketNotifierSourceDispatch (source=0x55ff3ed4e220) at /home/haufler/git/qt5.15.13/qt5/qtbase/src/corelib/kernel/qeventdispatcher_glib.cpp:107 #22 0x00007fd471b1bd3b in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0