Bug#985994: kwin-x11: crashes randomly on ALT-TAB for switching between windows

[Russell Coker <russell@coker.com.au>]

Package: kwin-x11
Version: 4:5.20.5-1
Severity: normal

kwin_x11 will crash if I repeatedly use ALT-TAB to switch between windows.
Once every 5 to 10 window switches it will crash.

# coredumpctl info
           PID: 120123 (kwin_x11)
           UID: 1000 (etbe)
           GID: 1000 (etbe)
        Signal: 11 (SEGV)
     Timestamp: Sun 2021-03-28 02:50:46 AEDT (46s ago)
  Command Line: /usr/bin/kwin_x11 --crashes 1
    Executable: /usr/bin/kwin_x11
 Control Group: /user.slice/user-1000.slice/session-4.scope
          Unit: session-4.scope
         Slice: user-1000.slice
       Session: 4
     Owner UID: 1000 (etbe)
       Boot ID: ea470da9187243d6b412d447fccb3e3d
    Machine ID: 1677a0a8ceed4907a4efd7544ca73ae0
      Hostname: liv
       Storage: /var/lib/systemd/coredump/core.kwin_x11.1000.ea470da9187243d6b412d447fccb3e3d.12012>
       Message: Process 120123 (kwin_x11) of user 1000 dumped core.
                
                Stack trace of thread 120123:
                #0  0x00007f49c3823ce1 n/a (/lib/x86_64-linux-gnu/libc-2.31.so (deleted) + 0x3bce1)


-- System Information:
Debian Release: bullseye/sid
  APT prefers testing
  APT policy: (500, 'testing'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 5.10.0-4-amd64 (SMP w/2 CPU threads)
Kernel taint flags: TAINT_WARN
Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=UTF-8), LANGUAGE=en_AU:en
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: SELinux: enabled - Mode: Enforcing - Policy name: default

Versions of packages kwin-x11 depends on:
ii  kwin-common                                   4:5.20.5-1
ii  libc6                                         2.31-10
ii  libepoxy0                                     1.5.5-1
ii  libgcc-s1                                     10.2.1-6
ii  libkf5configcore5                             5.78.0-4
ii  libkf5coreaddons5                             5.78.0-4
ii  libkf5crash5                                  5.78.0-3
ii  libkf5i18n5                                   5.78.0-2
ii  libkf5quickaddons5                            5.78.0-2
ii  libkf5windowsystem5                           5.78.0-2
ii  libkwaylandserver5 [libkwaylandserver5-5.20]  5.20.5-1
ii  libkwineffects12a                             4:5.20.5-1
ii  libkwinglutils12                              4:5.20.5-1
ii  libkwinxrenderutils12                         4:5.20.5-1
ii  libqt5core5a                                  5.15.2+dfsg-5
ii  libqt5dbus5                                   5.15.2+dfsg-5
ii  libqt5gui5                                    5.15.2+dfsg-5
ii  libqt5widgets5                                5.15.2+dfsg-5
ii  libqt5x11extras5                              5.15.2-2
ii  libstdc++6                                    10.2.1-6
ii  libx11-6                                      2:1.7.0-2
ii  libxcb-composite0                             1.14-3
ii  libxcb-cursor0                                0.1.1-4
ii  libxcb-keysyms1                               0.4.0-1+b2
ii  libxcb-randr0                                 1.14-3
ii  libxcb-render0                                1.14-3
ii  libxcb-shape0                                 1.14-3
ii  libxcb-xfixes0                                1.14-3
ii  libxcb1                                       1.14-3
ii  libxi6                                        2:1.7.10-1

kwin-x11 recommends no packages.

kwin-x11 suggests no packages.

-- no debconf information