Regression: Immediate Blender Crash in 4.0 when updating image data blocks during playback #109168

New Issue

Julieta Riley · 2023-06-20T19:21:39+02:00

Julieta Riley commented

2023-06-20 19:21:39 +02:00

System Information
Operating system: Windows-10-10.0.19044-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 535.98

Blender Version
Broken: version: 4.0.0 Alpha, branch: main, commit date: 2023-06-17 23:39, hash: 0b71a1f054c1
Caused by 65fc10bd33

Short description of error
Immediate crash when updating image data blocks from frame change handler & frame change handler is no longer visited after stopping playback (as it was in 3.6)

Exact steps for others to reproduce the error

IMPORTANT - The crash only happens if not debugging, so ensure Blender is launched from the exe directly, not from vs code etc

The addon has been reduced as much as possible from 8000 lines of code to a few hundred. The addon is doing the following:

frame change handler mutes render layer nodes
if playback and not scrubbing, handler calls scene_helpers.update_rendered_image_paths(scene.name) which loads the EXR for the current frame into the image node, then calls render.render to force the play head to wait until the compositor has finished processing ( render layer node muted to ensure 3d viewport not rendered (just compositor))
after playback muted nodes are unmuted (this doesn't appear to work in 4.0, is this a separate bug or an intentional handler change?)

test1

download zip file https://www.dropbox.com/s/demp7a7it3h77jz/blend%20file%20and%20test%20addon.zip?dl=1
unzip
open blender 3.6
install the addon (make sure no other addons are installed that use frame change handlers)
open the included blend file titled 'testrel blender 3.6.blend'
go to the compositor and ensure use nodes and backdrop are enabled.
press play
the image will update each frame and be shown in the compositor backdrop.

test 2

Open Blender 4.0
install the addon again
open the blend file titled 'testrel blender 4.0.blend'
go to the compositor
press play
will crash usually immediately but sometimes after several iterations of the timeline.

**System Information** Operating system: Windows-10-10.0.19044-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 535.98 **Blender Version** Broken: version: 4.0.0 Alpha, branch: main, commit date: 2023-06-17 23:39, hash: `0b71a1f054c1` Caused by 65fc10bd33fbe19a8beb2b7319b1b0bbdc52f1cb **Short description of error** Immediate crash when updating image data blocks from frame change handler & frame change handler is no longer visited after stopping playback (as it was in 3.6) **Exact steps for others to reproduce the error** **IMPORTANT - The crash only happens if not debugging, so ensure Blender is launched from the exe directly, not from vs code etc** The addon has been reduced as much as possible from 8000 lines of code to a few hundred. The addon is doing the following: - frame change handler mutes render layer nodes - if playback and not scrubbing, handler calls scene_helpers.update_rendered_image_paths(scene.name) which loads the EXR for the current frame into the image node, then calls render.render to force the play head to wait until the compositor has finished processing ( render layer node muted to ensure 3d viewport not rendered (just compositor)) - after playback muted nodes are unmuted (this doesn't appear to work in 4.0, is this a separate bug or an intentional handler change?) ### test1 1. download zip file https://www.dropbox.com/s/demp7a7it3h77jz/blend%20file%20and%20test%20addon.zip?dl=1 2. unzip 3. open blender 3.6 4. install the addon (make sure no other addons are installed that use frame change handlers) 5. open the included blend file titled 'testrel blender 3.6.blend' 6. go to the compositor and ensure use nodes and backdrop are enabled. 7. press play 8. the image will update each frame and be shown in the compositor backdrop. ### test 2 1. Open Blender 4.0 2. install the addon again 3. open the blend file titled 'testrel blender 4.0.blend' 4. go to the compositor 5. press play 6. will crash usually immediately but sometimes after several iterations of the timeline.

image.png

18 KiB

Julieta Riley added the

labels 2023-06-20 19:21:39 +02:00

Julieta Riley referenced this issue

2023-06-20 19:31:25 +02:00

Compositor ACCESS VIOLATION when updating datablocks from handlers #107248

YimingWu commented

2023-06-21 04:19:23 +02:00

Related frame change handler bugs: #109127

Philipp Oeser commented

2023-06-21 10:50:07 +02:00

Unable to repro a crash on linux in 4.0 hash c78ea4cefc

after playback muted nodes are unmuted (this doesn't appear to work in 4.0, is this a separate bug or an intentional handler change?)

Unable to repro this in 4.0 either, do you mean the Render Layer node is supposed to be unmuted after playback stopped?
(this does not appear to be working in 3.6 either).

then calls render.render to force the play head to wait until the compositor has finished processing ( render layer node muted to ensure 3d viewport not rendered (just compositor))

Could 16d329da28 help here in any way?

Unable to repro a crash on linux in 4.0 hash c78ea4cefcd3 >after playback muted nodes are unmuted (this doesn't appear to work in 4.0, is this a separate bug or an intentional handler change?) Unable to repro this in 4.0 either, do you mean the Render Layer node is supposed to be unmuted after playback stopped? (this does not appear to be working in 3.6 either). >then calls render.render to force the play head to wait until the compositor has finished processing ( render layer node muted to ensure 3d viewport not rendered (just compositor)) Could 16d329da284c20e9dcfc0a60dcfc9b6e213ad3e0 help here in any way?

Julieta Riley commented

2023-06-21 16:53:40 +02:00

@lichtwerk just tried todays 4.0 build. It didn't crash immediately, but after leaving it to run for 30 seconds and stopping and starting playback a few times it did crash again, and then afterwards every time I opened Blender and tried again, it then crashed immediately each time. Perhaps windows related?

logs attached.

I don't think 16d329da28 will help, because in our case render.render is being used to force the playhead to not move to the next frame until the compositor has finished processing. Without doing that the playhead will move to the next frame with the backdrop only partially drawn.

For us the frame change handler is definitely being revisited when the playhead stops, and therefore able to unmute the render layer node. Video attached of 3.6 and below behaviour, render layer node is initially un-muted, then after pressing play it's muted, then when stopping playback it's once again un-muted by line 60 in handlers.py

@lichtwerk just tried todays 4.0 build. It didn't crash immediately, but after leaving it to run for 30 seconds and stopping and starting playback a few times it did crash again, and then afterwards every time I opened Blender and tried again, it then crashed immediately each time. Perhaps windows related? logs attached. I don't think 16d329da28 will help, because in our case render.render is being used to force the playhead to not move to the next frame until the compositor has finished processing. Without doing that the playhead will move to the next frame with the backdrop only partially drawn. For us the frame change handler is definitely being revisited when the playhead stops, and therefore able to unmute the render layer node. Video attached of 3.6 and below behaviour, render layer node is initially un-muted, then after pressing play it's muted, then when stopping playback it's once again un-muted by line 60 in handlers.py

blender_debug_output.txt

1.6 KiB

2023-06-21 15-50-11.mp4

4.2 MiB

testrel blender 4.0.crash.txt

8.2 KiB

Philipp Oeser commented

2023-06-21 17:22:49 +02:00

Checked 3.6 again, muted nodes dont get unmuted there for me.

Revisited 4.0 again as well, what I can say (without further checking yet) is that I indeed get a freeze if I

install the addon
open the file
playback (the Render Layers node get muted)
stop playback (the render Layer node remains muted)
mute the node by hand
playback
freeze

Checked 3.6 again, muted nodes dont get unmuted there for me. Revisited 4.0 again as well, what I can say (without further checking yet) is that I indeed get a freeze if I - install the addon - open the file - playback (the Render Layers node get muted) - stop playback (the render Layer node remains muted) - mute the node by hand - playback - freeze

Sergey Sharybin commented

2023-06-21 17:28:02 +02:00

I can not reproduce on macOS, neither in release nor debug+ASAN modes. Don't currently have access to Windows machine, maybe someone around the bug tracker can try testing it there? =

@Julieta-Riley You mentioned running Blender from outside of VS Code is crucial. Am I right that you have a Blender development environment? If so, maybe you can try building RelWithDebInfo configuration, run it, when it crashes make a dump, and open the dump with WinDbg to get a meaningful backtrace?

I can not reproduce on macOS, neither in release nor debug+ASAN modes. Don't currently have access to Windows machine, maybe someone around the bug tracker can try testing it there? = @Julieta-Riley You mentioned running Blender from outside of VS Code is crucial. Am I right that you have a Blender development environment? If so, maybe you can try building `RelWithDebInfo` configuration, run it, when it crashes make a dump, and open the dump with WinDbg to get a meaningful backtrace?

Julieta Riley commented

2023-06-21 17:31:47 +02:00

@lichtwerk I've just retried in 3.6 starting in factory mode then re-enabled the addon, and the handler is still being hit one final time and successfully unmuting the render layer node when playback stops. Really strange that it's not happening for you. Possibly OS related? Although that would be strange because we have a few thousand users and non have reported this issue in 3.6 and below.

After you get the freeze, if you then force blender to close, and re-start/re-open the file and press play, do you then get an immediate crash the same as us?

@lichtwerk I've just retried in 3.6 starting in factory mode then re-enabled the addon, and the handler is still being hit one final time and successfully unmuting the render layer node when playback stops. Really strange that it's not happening for you. Possibly OS related? Although that would be strange because we have a few thousand users and non have reported this issue in 3.6 and below. After you get the freeze, if you then force blender to close, and re-start/re-open the file and press play, do you then get an immediate crash the same as us?

Julieta Riley commented

2023-06-21 17:34:23 +02:00

@Sergey We're just using Jacques Lucke's VS code extension to allow us to debug the python addons. We're not set up for Blender development.

Julieta Riley commented

2023-06-21 17:35:34 +02:00

@Sergey we can try though if someone can provide us a link to step by step instructions to do what you've said?

Richard Antalik commented

2023-06-21 18:49:01 +02:00

Can confirm, will bisect.

Richard Antalik changed title from ~~Immediate Blender Crash in 4.0 when updating image data blocks during playback (works in 3.6 and below) & frame change handler is no longer visited after stopping playback~~ to Immediate Blender Crash in 4.0 when updating image data blocks during playback

2023-06-21 20:36:25 +02:00

Richard Antalik changed title from ~~Immediate Blender Crash in 4.0 when updating image data blocks during playback~~ to Regression: Immediate Blender Crash in 4.0 when updating image data blocks during playback

2023-06-21 20:36:35 +02:00

Richard Antalik added

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Regression: Immediate Blender Crash in 4.0 when updating image data blocks during playback #109168

test1

test 2