Bug 467959

Summary: kwin_wayland crashes in KWin::ScreenCastStream::enqueue() when screen recording with OBS 29.1 beta
Product: [Plasma] kwin Reporter: Schlaefer <openmail+kde>
Component: wayland-genericAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED DUPLICATE    
Severity: crash CC: kde, kostadinshishmanov, nate, postix
Priority: NOR    
Version First Reported In: 5.27.3   
Target Milestone: ---   
Platform: Other   
OS: Linux   
See Also: https://bugs.kde.org/show_bug.cgi?id=469949
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description Schlaefer 2023-03-30 07:31:46 UTC 
SUMMARY
Testing OBS 29.1 Wayland via flatpak there capture errors like flickering, jumping images, blackscreens. Investigating further it developed into a reproducible kwin_wayland crash.

STEPS TO REPRODUCE
1. Install flatpak
2. Add flatpak beta: "flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo"
3. Install obs-studio beta: "flatpak install com.obsproject.Studio"
4. Start capturing video with "Screen Capture (PipeWire)" or "Window Capture (PipeWire)"

OBSERVED RESULT

Capturing video results is distorted, esp. if the mouse pointer is moved above the OBS capture preview or the captured window (screen). A informal chat over at the OBS discord was hinting to a potential plasma upstream issue.

Testing on a different machine and distro confirms and also leads to reproducible kwin_wayland crashes.

Video example for both in attachment.

EXPECTED RESULT

Capturing video without flicker, blackscreen or crashes (as in OBS 29.0.2 and prior).

SOFTWARE/OS VERSIONS
Included in file  attachment.
Comment 1 Schlaefer 2023-03-30 07:34:59 UTC 
Attachment files for initial report: https://files.catbox.moe/u3w2pa.zip
Comment 2 David Edmundson 2023-03-31 10:28:59 UTC 
Pasting relevant part in-line:

     Module .kwin_wayland-wrapped without build-id.
                                                         Stack trace of thread 1760:
                                                         #0  0x00007f00317b203d pw_stream_queue_buffer (libpipewire-0.3.so.0 + 0xa903d)
                                                         #1  0x000000000047c9c2 _ZN4KWin16ScreenCastStream7enqueueEv (.kwin_wayland-wrapped + 0x7c9c2)
                                                         #2  0x00007f0032d03465 n/a (libQt5Core.so.5 + 0x303465)
                                                         #3  0x00007f0032d0696f _ZN15QSocketNotifier9activatedE17QSocketDescriptorNS_4TypeENS_14QPrivateSignalE (libQt5Core.so.5 + 0x30696f)
                                                         #4  0x00007f0032d07175 _ZN15QSocketNotifier5eventEP6QEvent (libQt5Core.so.5 + 0x307175)
                                                         #5  0x00007f0031970ffe _ZN19QApplicationPrivate13notify_helperEP7QObjectP6QEvent (libQt5Widgets.so.5 + 0x170ffe)
                                                         #6  0x00007f0032ccb5c8 _ZN16QCoreApplication15notifyInternal2EP7QObjectP6QEvent (libQt5Core.so.5 + 0x2cb5c8)
                                                         #7  0x00007f0032d21353 _ZN27QEventDispatcherUNIXPrivate23activateSocketNotifiersEv (libQt5Core.so.5 + 0x321353)
                                                         #8  0x00007f0032d21827 _ZN20QEventDispatcherUNIX13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5 + 0x321827)
                                                         #9  0x0000000000564f8d _ZN23QUnixEventDispatcherQPA13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (.kwin_wayland-wrapped + 0x164f8d)
                                                         #10 0x00007f0032cc9fc3 _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5 + 0x2c9fc3)
                                                         #11 0x00007f0032cd24c6 _ZN16QCoreApplication4execEv (libQt5Core.so.5 + 0x2d24c6)
                                                         #12 0x000000000044c41e main (.kwin_wayland-wrapped + 0x4c41e)
                                                         #13 0x00007f003102924e __libc_start_call_main (libc.so.6 + 0x2924e)
                                                         #14 0x00007f0031029309 __libc_start_main@@GLIBC_2.34 (libc.so.6 + 0x29309)
                                                         #15 0x000000000044e4c5 _start (.kwin_wayland-wrapped + 0x4e4c5)
Comment 3 David Edmundson 2023-05-26 10:25:00 UTC 

*** This bug has been marked as a duplicate of bug 469949 ***