Bug#996550: libqt5gui5: Trap in LibQXCB-GLX with 100% cpu usage after QOpenGLContext::create() called

[anthony <lkphantom1995@gmail.com>]

Package: libqt5gui5
Version: 5.15.2+dfsg-9
Severity: important
X-Debbugs-Cc: lkphantom1995@gmail.com

Dear Maintainer,

I'm stuck up when calling QOpenGLContext::create(), it didn't return, and one cpu 
was totally occupied by QSGRenderThread, it looks like dead loop occurs in that
thread.

this's not always happening; and sometimes UI rendering error (like unexpected 
chessboard-like pattern shows up in my GL render area) happens before this problem
occurs.

i'm using libGLX_mesa, and i'm not sure which side should responsible for this 
problem, so i send this bugreport to you.

Regards,

-- System Information:
Debian Release: 11.1
  APT prefers stable-security
  APT policy: (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 5.10.46.xeon.ll (SMP w/8 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages libqt5gui5 depends on:
ii  fontconfig                        2.13.1-4.2
ii  libc6                             2.31-13+deb11u2
ii  libdrm2                           2.4.104-1
ii  libegl1                           1.3.2-1
ii  libfontconfig1                    2.13.1-4.2
ii  libfreetype6                      2.10.4+dfsg-1
ii  libgbm1                           20.3.5-1
ii  libgcc-s1                         10.2.1-6
ii  libgl1                            1.3.2-1
ii  libglib2.0-0                      2.66.8-1
ii  libharfbuzz0b                     2.7.4-1
ii  libice6                           2:1.0.10-1
ii  libinput10                        1.16.4-3
ii  libjpeg62-turbo                   1:2.0.6-4
ii  libmd4c0                          0.4.7-2
ii  libmtdev1                         1.1.6-1
ii  libpng16-16                       1.6.37-3
ii  libqt5core5a [qtbase-abi-5-15-2]  5.15.2+dfsg-9
ii  libqt5dbus5                       5.15.2+dfsg-9
ii  libqt5network5                    5.15.2+dfsg-9
ii  libsm6                            2:1.2.3-1
ii  libstdc++6                        10.2.1-6
ii  libudev1                          247.3-6
ii  libx11-6                          2:1.7.2-1
ii  libx11-xcb1                       2:1.7.2-1
ii  libxcb-glx0                       1.14-3
ii  libxcb-icccm4                     0.4.1-1.1
ii  libxcb-image0                     0.4.0-1+b3
ii  libxcb-keysyms1                   0.4.0-1+b2
ii  libxcb-randr0                     1.14-3
ii  libxcb-render-util0               0.3.9-1+b1
ii  libxcb-render0                    1.14-3
ii  libxcb-shape0                     1.14-3
ii  libxcb-shm0                       1.14-3
ii  libxcb-sync1                      1.14-3
ii  libxcb-xfixes0                    1.14-3
ii  libxcb-xinerama0                  1.14-3
ii  libxcb-xinput0                    1.14-3
ii  libxcb-xkb1                       1.14-3
ii  libxcb1                           1.14-3
ii  libxkbcommon-x11-0                1.0.3-2
ii  libxkbcommon0                     1.0.3-2
ii  libxrender1                       1:0.9.10-1
ii  zlib1g                            1:1.2.11.dfsg-2

Versions of packages libqt5gui5 recommends:
ii  libqt5svg5             5.15.2-3
ii  qt5-gtk-platformtheme  5.15.2+dfsg-9

Versions of packages libqt5gui5 suggests:
ii  qt5-image-formats-plugins  5.15.2-2
ii  qtwayland5                 5.15.2-3

-- no debconf information