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GTK4 applications crash with SIGSEGV when using the Vulkan renderer (GSK) on Raspberry Pi 4 with the Broadcom V3D Vulkan driver from mesa-26.1.5-1.fc45. The crash occurs in v3d42_cmd_buffer_emit_gl_shader_state() inside libvulkan_broadcom.so. On a fresh Fedora 45 GNOME Workstation aarch64 install on Raspberry Pi 4 Model B Rev 1.5, the gnome-initial-setup process crashes approximately 15 seconds after rendering begins. GDM then restarts the session with a fallback user, which also crashes. This creates an infinite crash loop -- GDM alternates between gnome-initial-setup and gnome-initial-setup-2 users, crashing every ~70 seconds, with no recovery mechanism. Workaround: Setting GSK_RENDERER=gl in /etc/environment forces GTK4 to use the OpenGL/GLES renderer instead of Vulkan, completely avoiding the crash. Reproducible: Always Steps to Reproduce: 1. Write Fedora 45 Rawhide 20260731.n.0 Workstation aarch64 image to an SD card 2. Boot on Raspberry Pi 4 Model B 3. Wait for GDM to start and launch gnome-initial-setup 4. Observe crash within ~15 seconds of the setup wizard rendering Actual Results: gnome-initial-setup crashes with SIGSEGV (signal 11). The crash is 100% reproducible -- observed 6 consecutive crashes in a single boot with no successful render. GDM enters an infinite restart loop alternating between gnome-initial-setup and gnome-initial-setup-2 users. ``` Stack trace of thread 1966: #0 0x0000ffff807b147c v3d42_cmd_buffer_emit_gl_shader_state (libvulkan_broadcom.so + 0x12147c) #1 0x0000ffff8069f850 v3dv_cmd_buffer_emit_pre_draw (libvulkan_broadcom.so + 0xf850) #2 0x0000ffff806a00f8 cmd_buffer_draw (libvulkan_broadcom.so + 0x100f8) #3 0x0000ffff806a0240 v3dv_CmdDraw (libvulkan_broadcom.so + 0x10240) #4 0x0000ffffba714d00 gsk_gpu_shader_op_vk_command (libgtk-4.so.1 + 0x5e4d00) #5 0x0000ffffba71c8b8 gsk_vulkan_frame_submit_ops (libgtk-4.so.1 + 0x5ec8b8) #6 0x0000ffffba722d10 gsk_vulkan_frame_submit (libgtk-4.so.1 + 0x5f2d10) #7 0x0000ffffba708a00 gsk_gpu_frame_render (libgtk-4.so.1 + 0x5d8a00) #8 0x0000ffffba717d8c gsk_gpu_renderer_render (libgtk-4.so.1 + 0x5e7d8c) #9 0x0000ffffba6c7568 gsk_renderer_render (libgtk-4.so.1 + 0x597568) #10 0x0000ffffba325e70 surface_render_cb (libgtk-4.so.1 + 0x1f5e70) ... #24 0x0000aaaabc672fbc main (gnome-initial-setup + 0x12fbc) ``` Expected Results: gnome-initial-setup should render and function correctly using the V3D Vulkan driver on Raspberry Pi 4. Additional Information: Versions - Kernel: 7.2.0-0.rc5.260729gfc02acf6ac0c.43.fc45.aarch64 - Mesa: mesa-26.1.5-1.fc45.aarch64 (libvulkan_broadcom.so) - GTK4: gtk4-4.23.2-2.fc45.aarch64 - gnome-initial-setup: gnome-initial-setup-51~alpha-2.fc45.aarch64 - systemd: 261.2-1.fc45 - GDM: gdm-51~alpha-2.fc45.aarch64 - GNOME Shell: mutter 51.alpha - Hardware: Raspberry Pi 4 Model B Rev 1.5 (BCM2711, Broadcom V3D 4.2) - GPU driver: vc4-drm (kernel), v3d Vulkan (mesa)
Created attachment 2153412 [details] Gnome boot log with SIGSEGV
Created attachment 2153414 [details] Gnome boot log with GSK_RENDERER=gl workaround
Created attachment 2153415 [details] KDE boot log - no crash
Proposed as a Blocker for 45-beta by Fedora user jgroman using the blocker tracking app because: RPi Workstation image uses failing Vulkan driver by default, switching to OpenGL (which works) requires manual tweaks.
Hmmm, this is almost a case that GSK_RENDERER=cairo should be set globally during install. Yes it will be a bit slower, but its also going to be far more stable than hoping that there aren't any vulcan/GL/etc bugs in the drivers/firmware/etc on what will quickly be an old install image.
we'll want to retest this next week when mesa 26.2 lands.
The issue is resolved in the latest Fedora 45 Rawhide image: https://fedoraproject.org/wiki/Test_Results:Fedora_45_Rawhide_20260807.n.0_Summary - Kernel: 7.2.0-0.rc6.51.fc45 UPDATED - Mesa: 26.2.0-1.fc45 UPDATED - GTK4: 4.23.3-1.fc45 UPDATED - gnome-initial-setup: 51~beta-1.fc45 UPDATED - systemd: 261.2-1.fc45 NO CHANGE - GDM: 51~beta-1.fc45 UPDATED - GNOME Shell / Mutter: mutter 51~beta-1.fc45 UPDATED - U-Boot BIOS: 2026.10-rc1 UPDATED
Thanks for the update.