Public bug reported: GNOME49 can crash when dragging a window to screens with different scale factor.
I have two screens: a 4K screen with scale factor of 200% and a FullHD screen with a screen factor of 100%. The problem (sometimes) appears in Wayland under GNOME49 in Ubuntu 25.10. Particularly when the window is dragged slowly from one screen to the other. Using FLTK 1.5 either the WIP OpenGL branch or my Vulkan port, can result on crashes when dragging the window from the screen factor of 100% to a scale factor of 200%. The crash, as it reports, is due to a difference in scale factor and window size: wl_surface#52: error 2: Buffer size (933x29) must be an integer multiple of the buffer_scale (2). The crash does not happen on KDE Plasma or going the other way (from 200% to 100%). The difference between Plasma and GNOME is that Plasma switches scale factor only when the full window has transitioned (and there's even a small pause too, which helps), while GNOME transitions to the new scale factor immediately, sometimes even midway. The problem shows up when OpenGL or Vulkan is under heavy load. A simple triangle does not show the problem, so I cannot give you a simple test program. You can reproduce the issue with my Vulkan video player: https://mega.nz/file/6aBzwJRb#ekemi5M_ZV3TQlhdy1eNatYoZH4XMDFWzoa2yZfJP6E and this movie: https://mega.nz/file/LKIQHSjS#o3Kk5YNLKXU_9VqUoZHmklPnMmVqlj25-De9mzLXylw I have a log with all the Vulkan window sizes that are created (which when the Wayland buffer error appears reports a size that was not sent before): https://mega.nz/file/yT5j1RZT#be999_J0VYGRWgUs2pDG6ecHIzQOIft6GFLNUsb- tb8 I will keep debugging it to see if I can find out what window sends a 933x29 to Wayland. ProblemType: Bug DistroRelease: Ubuntu 25.10 Package: gnome-shell 49.0-1ubuntu1.2 ProcVersionSignature: Ubuntu 6.17.0-23.23-generic 6.17.13 Uname: Linux 6.17.0-23-generic x86_64 NonfreeKernelModules: nvidia_modeset nvidia ApportVersion: 2.33.1-0ubuntu3 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: ubuntu:GNOME Date: Thu May 7 14:18:10 2026 DisplayManager: gdm3 InstallationDate: Installed on 2025-11-17 (171 days ago) InstallationMedia: Ubuntu 25.04 "Plucky Puffin" - Release amd64 (20250415.3) RelatedPackageVersions: mutter-common 49.0-2ubuntu5.3 SourcePackage: gnome-shell UpgradeStatus: No upgrade log present (probably fresh install) ** Affects: gnome-shell (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug questing wayland-session -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2151816 Title: GNOME49 can crash when dragging a window to screens with different scale factor. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/2151816/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
