Crash in nvoglv64.dll entering edit mode on curve #94454

New Issue

eldee smith · 2021-12-29T01:51:31+01:00

eldee smith commented

2021-12-29 01:51:31 +01:00

System Information
Operating system: Windows-10-10.0.19043-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 3080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 472.39

Blender Version
Broken: version: 3.1.0 Alpha, branch: master, commit date: 2021-12-26 20:08, hash: 20b438d523
Worked: 2.93 LTS

Caused by eb0eb54d96

Blender crashes with an access violation in nvoglv64.dll when entering edit mode on a curve with the following script running. This worked fine in Blender 2.93 et al, so something has changed with object.to_mesh() that nvoglv64.dll does not like.
See the attached blend file, and run the embedded minimum repro crash_script text file- which is a simple GL handler that should use blf to display the number of mesh polygons in a curve.

# Blender 3.1.0, Commit date: 2021-12-26 20:08, Hash 20b438d523c9
bpy.ops.object.editmode_toggle()  # Operator

# backtrace
Exception Record:

ExceptionCode         : EXCEPTION_ACCESS_VIOLATION
Exception Address     : 0x00007FF9798BBDD0
Exception Module      : nvoglv64.dll
Exception Flags       : 0x00000000
Exception Parameters  : 0x2
	Parameters[0] : 0x0000000000000000
	Parameters[1] : 0x0000000000000000


Stack trace:
nvoglv64.dll        :0x00007FF9798BBDD0  Symbols not available

# Python backtrace

the repro script, for posterity:

import bpy, blf

def draw_test():
    ui_scale = bpy.context.preferences.system.ui_scale
    blf.color(0, 1,1,0,1)
    blf.size(0, int(12 * ui_scale), 72)

    blf.position(0, int(20 * ui_scale), int(bpy.context.region.height) - int(200 * ui_scale), 0)
    blf.draw(0, f"With the curve selected, enter edit mode.")

    blf.position(0, int(20 * ui_scale), int(bpy.context.region.height) - int(220 * ui_scale), 0)
    blf.draw(0, f"If it doesn't crash immediately, try selecting a few points.")

    if bpy.context.mode != 'EDIT_CURVE':
        return

    obj = bpy.context.active_object
    value = 0
    if obj is not None and obj.type == 'CURVE':
        # NOTE: crash is caused by this:
        me = obj.to_mesh()
        value = len(me.polygons)
        obj.to_mesh_clear()
    
    blf.position(0, int(20 * ui_scale), int(bpy.context.region.height) - int(240 * ui_scale), 0)
    blf.draw(0, f"We'll never get to this point, but the curve has {value} polygons.")

handler = None
def register():
    global handler
    handler = bpy.types.SpaceView3D.draw_handler_add(draw_test, (), 'WINDOW', 'POST_PIXEL')
    
def unregister():
    global handler
    if handler is not None:
        bpy.types.SpaceView3D.draw_handler_remove(handler, 'WINDOW')
        handler = None
    
if __name__ == "__main__":
    register()

edit: apparently the blend file did not attach, here it is again
crash.blend

You can get around it passing the evaluated object to to_mesh, see:
crash_corrected.blend

**System Information** Operating system: Windows-10-10.0.19043-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 3080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 472.39 **Blender Version** Broken: version: 3.1.0 Alpha, branch: master, commit date: 2021-12-26 20:08, hash: `20b438d523` Worked: 2.93 LTS Caused by eb0eb54d96 Blender crashes with an access violation in nvoglv64.dll when entering edit mode on a curve with the following script running. This worked fine in Blender 2.93 et al, so something has changed with object.to_mesh() that nvoglv64.dll does not like. See the attached blend file, and run the embedded minimum repro `crash_script` text file- which is a simple GL handler that should use blf to display the number of mesh polygons in a curve. ``` # Blender 3.1.0, Commit date: 2021-12-26 20:08, Hash 20b438d523c9 bpy.ops.object.editmode_toggle() # Operator # backtrace Exception Record: ExceptionCode : EXCEPTION_ACCESS_VIOLATION Exception Address : 0x00007FF9798BBDD0 Exception Module : nvoglv64.dll Exception Flags : 0x00000000 Exception Parameters : 0x2 Parameters[0] : 0x0000000000000000 Parameters[1] : 0x0000000000000000 Stack trace: nvoglv64.dll :0x00007FF9798BBDD0 Symbols not available # Python backtrace ``` the repro script, for posterity: ``` import bpy, blf def draw_test(): ui_scale = bpy.context.preferences.system.ui_scale blf.color(0, 1,1,0,1) blf.size(0, int(12 * ui_scale), 72) blf.position(0, int(20 * ui_scale), int(bpy.context.region.height) - int(200 * ui_scale), 0) blf.draw(0, f"With the curve selected, enter edit mode.") blf.position(0, int(20 * ui_scale), int(bpy.context.region.height) - int(220 * ui_scale), 0) blf.draw(0, f"If it doesn't crash immediately, try selecting a few points.") if bpy.context.mode != 'EDIT_CURVE': return obj = bpy.context.active_object value = 0 if obj is not None and obj.type == 'CURVE': # NOTE: crash is caused by this: me = obj.to_mesh() value = len(me.polygons) obj.to_mesh_clear() blf.position(0, int(20 * ui_scale), int(bpy.context.region.height) - int(240 * ui_scale), 0) blf.draw(0, f"We'll never get to this point, but the curve has {value} polygons.") handler = None def register(): global handler handler = bpy.types.SpaceView3D.draw_handler_add(draw_test, (), 'WINDOW', 'POST_PIXEL') def unregister(): global handler if handler is not None: bpy.types.SpaceView3D.draw_handler_remove(handler, 'WINDOW') handler = None if __name__ == "__main__": register() ``` edit: apparently the blend file did not attach, here it is again [crash.blend](https://archive.blender.org/developer/F12780026/crash.blend) You can get around it passing the evaluated object to `to_mesh`, see: [crash_corrected.blend](https://archive.blender.org/developer/F12780484/crash_corrected.blend)

eldee smith commented

2021-12-29 01:51:31 +01:00

Added subscriber: @testure

champions commented

2021-12-29 02:22:50 +01:00

Added subscriber: @schampions

champions commented

2021-12-29 02:22:50 +01:00

This comment was removed by @schampions

*This comment was removed by @schampions*

Thomas Dinges commented

2021-12-29 11:04:18 +01:00

Added subscriber: @ThomasDinges

Philipp Oeser commented

2021-12-29 14:09:29 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2021-12-29 14:09:29 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Philipp Oeser commented

2021-12-29 14:09:29 +01:00

Can confirm, will check

Philipp Oeser commented

2021-12-29 15:06:34 +01:00

Added subscriber: @HooglyBoogly

Philipp Oeser commented

2021-12-29 15:06:34 +01:00

Caused by eb0eb54d96

You can get around it passing the evaluated object to to_mesh, see:
crash_corrected.blend

It is not totally obvious for me why this crashes (passing the non-evaluated curve) and the commit message would imply this is not generally a problem:

If the object isn't evaluated, it uses a temporary copy of the object
with modifiers removed to create the mesh in the same way.

So, I would still like @HooglyBoogly to take a look (it is just not nice to have working [in 2.93] scripts resulting in a crash all of a sudden without explanation somewhere -- even if 3.0 is a compatibility breaking release)
It is also not mentioned in [if it would be an expected breaking change] https://wiki.blender.org/wiki/Reference/Release_Notes/3.0/Python_API

Caused by eb0eb54d96 You can get around it passing the evaluated object to `to_mesh`, see: [crash_corrected.blend](https://archive.blender.org/developer/F12780484/crash_corrected.blend) It is not totally obvious for me why this crashes (passing the non-evaluated curve) and the commit message would imply this is not generally a problem: > If the object isn't evaluated, it uses a temporary copy of the object > with modifiers removed to create the mesh in the same way. So, I would still like @HooglyBoogly to take a look (it is just not nice to have working [in 2.93] scripts resulting in a crash all of a sudden without explanation somewhere -- even if 3.0 is a compatibility breaking release) It is also not mentioned in [if it would be an expected breaking change] https://wiki.blender.org/wiki/Reference/Release_Notes/3.0/Python_API

Hans Goudey commented

2021-12-29 15:17:44 +01:00

Unfortunately I can't reproduce this at the moment:
{F12780516 size=full}
Maybe I'm missing something?

Unfortunately I can't reproduce this at the moment: {[F12780516](https://archive.blender.org/developer/F12780516/image.png) size=full} Maybe I'm missing something?

Philipp Oeser commented

2021-12-29 15:28:51 +01:00

In #94454#1279834, @HooglyBoogly wrote:
Unfortunately I can't reproduce this at the moment:
Maybe I'm missing something?

Is this crash.blend? or crash_corrected.blend?
Are you mouse-selecting points in editmode?
Have you done extrusion prior?

> In #94454#1279834, @HooglyBoogly wrote: > Unfortunately I can't reproduce this at the moment: > Maybe I'm missing something? Is this `crash.blend`? or `crash_corrected.blend`? Are you mouse-selecting points in editmode? Have you done extrusion prior?

Hans Goudey commented

2021-12-29 16:59:48 +01:00

Oops! Apparently I was using crash_corrected.blend. I can reproduce it now. I'll look into this.

Oops! Apparently I was using `crash_corrected.blend`. I can reproduce it now. I'll look into this.

Hans Goudey self-assigned this 2021-12-29 23:44:46 +01:00

Hans Goudey commented

2021-12-29 23:44:46 +01:00

I've found the fix, it was a relatively simple mistake in eb0eb54d96. However, based on the code there I would strongly recommend you use @lichtwerk's corrected version that uses a depsgraph to get the actual evaluated mesh (or a copy of it anyway).

I've found the fix, it was a relatively simple mistake in eb0eb54d96. However, based on the code there I would strongly recommend you use @lichtwerk's corrected version that uses a depsgraph to get the actual evaluated mesh (or a copy of it anyway).

blender-admin commented

2021-12-29 23:53:02 +01:00

This issue was referenced by 50c39ff8fe

This issue was referenced by 50c39ff8fe041153bda41657a694e0b154b8cd65

blender-admin commented

2021-12-29 23:53:02 +01:00

This issue was referenced by c0fdf16561

This issue was referenced by c0fdf16561034f85aadae8a513db16144609b821

Hans Goudey commented

2021-12-29 23:53:14 +01:00

Changed status from 'Confirmed' to: 'Resolved'

Hans Goudey closed this issue

2021-12-29 23:53:14 +01:00

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Crash in nvoglv64.dll entering edit mode on curve #94454