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  1. Qt
  2. QTBUG-92054

Crash on simulated touch input via uinput at xi2ProcessTouch

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Details

    • Linux/X11

    Description

      SUMMARY

      Simulating touch events via uinput and rapidly removing and adding a simulated device back while sending input events crashes any Qt program (I have tested so far at least, which includes KDE programs like Konsole, KCharselect as well as Subsurface). Programs like firefox or xterm are unaffected.

      STEPS TO REPRODUCE
       

      Backtrace I got from KCharSelect via KDE's crash report dialog:

      #4  0x00007ff8f1e0a4f3 in QXcbConnection::xi2ProcessTouch(void*, QXcbWindow*) () from /usr/lib/libQt5XcbQpa.so.5
#5  0x00007ff8f1ddb84f in QXcbConnection::handleXcbEvent(xcb_generic_event_t*) () from /usr/lib/libQt5XcbQpa.so.5
#6  0x00007ff8f1ddcc69 in QXcbConnection::processXcbEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5XcbQpa.so.5
#7  0x00007ff8f1e00164 in ?? () from /usr/lib/libQt5XcbQpa.so.5
#8  0x00007ff8f4a62b84 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#9  0x00007ff8f4ab6c21 in ?? () from /usr/lib/libglib-2.0.so.0
#10 0x00007ff8f4a613b1 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#11 0x00007ff8f6283691 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#12 0x00007ff8f62293ac in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#13 0x00007ff8f6231844 in QCoreApplication::exec() () from /usr/lib/libQt5Core.so.5
#14 0x000055db93c547c5 in ?? ()
#15 0x00007ff8f5bf0b25 in __libc_start_main () from /usr/lib/libc.so.6
#16 0x000055db93c5488e in ?? ()
[Inferior 1 (process 6631) detached]

      Attached is the output of `libinput debug-events` during the crash.

      I originally reported this to the KDE team, but they referred me here: https://bugs.kde.org/show_bug.cgi?id=434733

      Attachments

        1. input.log
          12 kB
        2. virtual-device.txt
          1 kB

        Issue Links

          relates to

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-119030 xcb plugin mixes up touch events for multiple windows

          • P1: Critical - Urgent and Important, will STOP the release if matched with set FixVersion field. This includes regressions from the last version that are not edge cases; Data loss; Build issues; All but the most unlikely crashes/lockups/hanging; Serious usability issues and embarrassing bugs & Bugs critical to a deliverable. This is the highest possible priority for requirements.
          • Closed

          Suggestion - Public suggestions QTBUG-94190 Support x11 standalone mode with window manager functions

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Reported

          Suggestion - Public suggestions QTBUG-35968 support native event in qtestlib

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Open
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              axelspoerl Axel Spoerl
              hmh HMH
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              Dates

                Created:
                Updated:
                Resolved:

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