Blender 5.1.2 dumps core with no clear cause - fix

Used blender a couple of weeks ago and it worked fine. Tried opening it today, and it crashed with some python errors about plugins. So I removed those from ~/.config/blender/5.1/extensions/user_default but no help. Uninstalled and reinstalled Blender and its dependencies, same. Other than a blank window appearing for a few seconds, the following was all I saw, even with debug enabled:

me@mine ~ $ blender -d
Switching to fully guarded memory allocator.
Blender 5.1.2
Build: 2026-05-19 10:38:26 Linux Release
argv[0] = blender
argv[1] = -d
Add-on not loaded: "space_view3d_pie_menus", cause: No module named 'space_view3d_pie_menus'
Add-on not loaded: "space_view3d_modifier_tools", cause: No module named 'space_view3d_modifier_tools'
Add-on not loaded: "object_boolean_tools", cause: No module named 'object_boolean_tools'
Add-on not loaded: "add_mesh_extra_objects", cause: No module named 'add_mesh_extra_objects'
Add-on not loaded: "add_curve_extra_objects", cause: No module named 'add_curve_extra_objects'
Add-on not loaded: "add_mesh_BoltFactory", cause: No module named 'add_mesh_BoltFactory'
Add-on not loaded: "mesh_looptools", cause: No module named 'mesh_looptools'
Add-on not loaded: "bl_ext.user_default.nd", cause: No module named 'bl_ext.user_default.nd'
Add-on not loaded: "bl_ext.user_default.CAD_Sketcher", cause: No module named 'bl_ext.user_default.CAD_Sketcher'
Add-on not loaded: "bl_ext.user_default.fabex", cause: No module named 'bl_ext.user_default.fabex'
Writing: /tmp/blender.crash.txt
Segmentation fault         (core dumped) blender -d

me@mine ~ $ cat /tmp/blender.crash.txt
# Blender 5.1.2, Commit date: 2026-05-18 13:43, Hash ec6e62d40fa9

# backtrace
blender(+0x25a94fd) [0x62fb99ed24fd]
blender(+0x18bc633) [0x62fb991e5633]
/usr/lib/libc.so.6(+0x3e270) [0x7683eb132270]
/usr/lib/libSPIRV-Tools-opt.so(+0x5b006) [0x7683e91d6006]
/usr/lib/libSPIRV-Tools-opt.so(_ZNSt17_Function_handlerIFbPKjEZNK8spvtools3opt11Instruction11ForEachInIdERKSt8functionIFvS1_EEEUlS1_E_E9_M_invokeERKSt9_Any_dataOS1_+0x38) [0x7683e91cec78]
/usr/lib/libSPIRV-Tools-opt.so(_ZN8spvtools3opt17AggressiveDCEPass21AddOperandsToWorkListEPKNS0_11InstructionE+0xb5) [0x7683e91d5e95]
/usr/lib/libSPIRV-Tools-opt.so(_ZN8spvtools3opt17AggressiveDCEPass15ProcessWorkListEPNS0_8FunctionE+0x5a) [0x7683e91dad1a]
/usr/lib/libSPIRV-Tools-opt.so(_ZN8spvtools3opt17AggressiveDCEPass13AggressiveDCEEPNS0_8FunctionE+0xb4) [0x7683e91daec4]
/usr/lib/libSPIRV-Tools-opt.so(_ZN8spvtools3opt17AggressiveDCEPass11ProcessImplEv+0xd9) [0x7683e91dcc69]
/usr/lib/libSPIRV-Tools-opt.so(_ZN8spvtools3opt4Pass3RunEPNS0_9IRContextE+0x2a) [0x7683e9315e7a]
/usr/lib/libSPIRV-Tools-opt.so(_ZN8spvtools3opt11PassManager3RunEPNS0_9IRContextE+0x15e) [0x7683e93171fe]
/usr/lib/libSPIRV-Tools-opt.so(_ZNK8spvtools9Optimizer3RunEPKjmPSt6vectorIjSaIjEEP23spv_optimizer_options_t+0x189) [0x7683e9311369]
/usr/lib/libshaderc_shared.so.1(+0x14f1d) [0x7683ff6e3f1d]
/usr/lib/libshaderc_shared.so.1(+0x167c9) [0x7683ff6e57c9]
/usr/lib/libshaderc_shared.so.1(shaderc_compile_into_spv+0x12) [0x7683ff6e6052]
blender(+0x299ec31) [0x62fb9a2c7c31]
blender(+0x299c3e9) [0x62fb9a2c53e9]
blender(+0x272469b) [0x62fb9a04d69b]
blender(+0x2725b97) [0x62fb9a04eb97]
blender(+0x288d356) [0x62fb9a1b6356]
blender(+0x288d70d) [0x62fb9a1b670d]
/usr/lib/libstdc++.so.6(+0xea659) [0x7683eb3fa659]
/usr/lib/libc.so.6(+0x97739) [0x7683eb18b739]
/usr/lib/libc.so.6(+0x11bedc) [0x7683eb20fedc]

# Python backtrace
me@mine ~ $ 

If this happens to you, and you are using the Vulkan backend, try this:

blender -d --gpu-backend opengl

If it now works, set the System - Display Graphics - Backend to OpenGL. Seems like a Vulkan / video driver issue.

2 Likes

Good to know. I was already using opengl as the backend and blender fired right up. However, I did change it to vulkan and can confirm that blender does in fact fail. So thank you for this information. Should be helpful to more than one person.

Blender released LTS version 5.2 with a good number of fixes for several kind of crashes. It should be available in the official repos soon.