Regression: Crash on changing view type with adjustment layer strips #97356

New Issue

a · 2022-04-15T14:44:09+02:00

a commented

2022-04-15 14:44:09 +02:00

System Information
Operating system: Windows 8.1
Graphics card: NVIDIA GeForce GT 750M (5+years old)

Blender Version
Broken: 3.2.0 Alpha, master branch from git
Worked: 3.2.0 Alpha from 2 weeks ago (so a recent regression). 3.1.0 release and older.
Caused by 277fa2f441

Short description of error

Simple operations in VSE like adding a strip and then changing the View Type will cause a crash. Reported to be an access violation. This has been happening on the Alpha build for the past couple of weeks.

Exact steps for others to reproduce the error

Default startup
Change Editor Type to 'Video Sequencer'
Change View Type to 'Sequencer'
Add adjustment layer
Add second adjustment layer
Change View Type to Preview
Crash

**System Information** Operating system: Windows 8.1 Graphics card: NVIDIA GeForce GT 750M (5+years old) **Blender Version** Broken: 3.2.0 Alpha, master branch from git Worked: 3.2.0 Alpha from 2 weeks ago (so a recent regression). 3.1.0 release and older. Caused by 277fa2f441 **Short description of error** Simple operations in VSE like adding a strip and then changing the View Type will cause a crash. Reported to be an access violation. This has been happening on the Alpha build for the past couple of weeks. **Exact steps for others to reproduce the error** - Default startup - Change Editor Type to 'Video Sequencer' - Change View Type to 'Sequencer' - Add adjustment layer - Add second adjustment layer - Change View Type to Preview - Crash

a commented

2022-04-15 14:44:09 +02:00

Added subscriber: @blenderbug12345

blender-admin commented

2022-04-15 14:44:09 +02:00

#97507 was marked as duplicate of this issue

blender-admin commented

2022-04-15 14:44:09 +02:00

#97455 was marked as duplicate of this issue

a commented

2022-04-15 14:50:18 +02:00

system-info.txt

blender.crash.txt

[system-info.txt](https://archive.blender.org/developer/F13002719/system-info.txt) [blender.crash.txt](https://archive.blender.org/developer/F13002721/blender.crash.txt)

Thomas Dinges commented

2022-04-15 15:56:49 +02:00

Added subscriber: @ThomasDinges

Thomas Dinges commented

2022-04-15 15:56:49 +02:00

Cannot reproduce the crash with 3.2.0 Alpha, branch: master, commit date: 2022-04-15 12:05, hash: 25196f8a36 on Windows.

Cannot reproduce the crash with 3.2.0 Alpha, branch: master, commit date: 2022-04-15 12:05, hash: `25196f8a36` on Windows.

a commented

2022-04-15 18:44:43 +02:00

Downloaded archived builds from https://builder.blender.org/download/daily/archive/

apr.15 blender-3.2.0-alpha+master.48ff456a4bda-windows.amd64-release CRASH
apr.08 blender-3.2.0-alpha+master.87a3bf33564b-windows.amd64-release CRASH
apr.05 blender-3.2.0-alpha+master.1d86d617823b-windows.amd64-release CRASH
apr.04 blender-3.2.0-alpha+master.b5f3f8ef1d52-windows.amd64-release CRASH
apr.04 blender-3.2.0-alpha+master.637fe6f5ff9c-windows.amd64-release OK
apr.03 blender-3.2.0-alpha+master.79ff65d07bac-windows.amd64-release OK
apr.01 blender-3.2.0-alpha+master.42853bacc973-windows.amd64-release OK
mar.01 blender-3.2.0-alpha+master.eb0f8317e231-windows.amd64-release OK

blender-3.2.0-alpha+master.b5f3f8ef1d52-windows.amd64-release introduced the editable channel names in the VSE so perhaps that's what is upsetting blender on my platform?

What other triage can I do?

Downloaded archived builds from https://builder.blender.org/download/daily/archive/ apr.15 blender-3.2.0-alpha+master.48ff456a4bda-windows.amd64-release CRASH apr.08 blender-3.2.0-alpha+master.87a3bf33564b-windows.amd64-release CRASH apr.05 blender-3.2.0-alpha+master.1d86d617823b-windows.amd64-release CRASH apr.04 blender-3.2.0-alpha+master.b5f3f8ef1d52-windows.amd64-release CRASH apr.04 blender-3.2.0-alpha+master.637fe6f5ff9c-windows.amd64-release OK apr.03 blender-3.2.0-alpha+master.79ff65d07bac-windows.amd64-release OK apr.01 blender-3.2.0-alpha+master.42853bacc973-windows.amd64-release OK mar.01 blender-3.2.0-alpha+master.eb0f8317e231-windows.amd64-release OK blender-3.2.0-alpha+master.b5f3f8ef1d52-windows.amd64-release introduced the editable channel names in the VSE so perhaps that's what is upsetting blender on my platform? What other triage can I do?

Pratik Borhade commented

2022-04-15 19:43:07 +02:00

Added subscriber: @PratikPB2123

Pratik Borhade commented

2022-04-15 20:09:21 +02:00

Thanks for testing on multiple builds.
I'm also unable to get the crash with your given steps (tested on last buildbot build and current master 7484f274dcdc9092dd5d85059e8d110572fe3b3c)

Thanks for testing on multiple builds. I'm also unable to get the crash with your given steps (tested on last buildbot build and current master `7484f274dcdc9092dd5d85059e8d110572fe3b3c`)

a commented

2022-04-15 21:01:03 +02:00

Well it looks like something weird is going on with channels. I can make the problem go away by testing the 'channel' pointer before referencing a function on it. so: channel && SEQ_channel_is_muted(channel).

I don't know if this is the correct fix, maybe the list in 'channels' is wrong or seq->machine is the wrong index. Whatever, the SEQ_channel_get_by_index is returning false and then everything blows up.

bool SEQ_render_is_muted(const ListBase *channels, const Sequence *seq)
{

  SeqTimelineChannel *channel = SEQ_channel_get_by_index(channels, seq->machine);

  return seq->flag & SEQ_MUTE || ( channel && SEQ_channel_is_muted(channel) );
}

Well it looks like something weird is going on with channels. I can make the problem go away by testing the 'channel' pointer before referencing a function on it. so: channel && SEQ_channel_is_muted(channel). I don't know if this is the correct fix, maybe the list in 'channels' is wrong or seq->machine is the wrong index. Whatever, the SEQ_channel_get_by_index is returning false and then everything blows up. ``` bool SEQ_render_is_muted(const ListBase *channels, const Sequence *seq) { SeqTimelineChannel *channel = SEQ_channel_get_by_index(channels, seq->machine); return seq->flag & SEQ_MUTE || ( channel && SEQ_channel_is_muted(channel) ); } ```

a commented

2022-04-16 01:14:07 +02:00

I updated the 'Exact steps' in the description.

I added some printfs and I see the crash when:
there are 2 Adjustment layers
the preview is displayed

With the crash inhibited (using the fix detailed above) I see channel=false just one-time per frame when the preview is displayed. I can move the cursor from frame 1 to frame 2 (say) and I see channel=false. If i move back to frame 1, or again to frame 2 then the channel=true. So this looks like something related to the way the VSE caches a rendered frame, and then doesn't re-render it if it's in the cache.

So when the preview is displayed, the code is called with channels=null, the FIRST time a frame is visited. Subsequent visits to an already cached frame seem to skip the logic.

I updated the 'Exact steps' in the description. I added some printfs and I see the crash when: there are 2 Adjustment layers the preview is displayed With the crash inhibited (using the fix detailed above) I see channel=false just one-time per frame when the preview is displayed. I can move the cursor from frame 1 to frame 2 (say) and I see channel=false. If i move back to frame 1, or again to frame 2 then the channel=true. So this looks like something related to the way the VSE caches a rendered frame, and then doesn't re-render it if it's in the cache. So when the preview is displayed, the code is called with channels=null, the FIRST time a frame is visited. Subsequent visits to an already cached frame seem to skip the logic.

Pratik Borhade commented

2022-04-16 05:15:13 +02:00

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

Pratik Borhade commented

2022-04-16 05:15:13 +02:00

Added subscriber: @iss

Pratik Borhade commented

2022-04-16 05:15:13 +02:00

Ok, thank you for the clarification (and looking in to the code side)
Crash is indeed introduced with recent feature of channel headers: 277fa2f441
@iss hi, can you check the proposed fix #97356#1341875

Ok, thank you for the clarification (and looking in to the code side) Crash is indeed introduced with recent feature of channel headers: 277fa2f441 @iss hi, can you check the proposed fix #97356#1341875

Pratik Borhade changed title from ~~VSE EXCEPTION_ACCESS_VIOLATION when performing simple operations~~ to Regression: Crash on changing view type with adjustment layer strips

2022-04-16 05:20:31 +02:00

Richard Antalik commented

2022-04-19 19:59:35 +02:00

Problem is in do_adjustment_impl() on line ListBase *channels = &seq->channels;. I have incorrectly assumed that this is for meta strips when I initialized this variable in quite a lot of functions.

Problem is in `do_adjustment_impl()` on line `ListBase *channels = &seq->channels;`. I have incorrectly assumed that this is for meta strips when I initialized this variable in quite a lot of functions.

Pratik Borhade commented

2022-04-20 06:04:47 +02:00

Added subscriber: @jaywalker

blender-admin commented

2022-04-21 00:05:57 +02:00

This issue was referenced by 3cef9ebaf8

This issue was referenced by 3cef9ebaf81053d80228f3ad43fa91e0ca75c542

Richard Antalik commented

2022-04-21 02:01:49 +02:00

Changed status from 'Confirmed' to: 'Resolved'

Richard Antalik closed this issue

2022-04-21 02:01:49 +02:00

Richard Antalik self-assigned this 2022-04-21 02:01:49 +02:00

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Regression: Crash on changing view type with adjustment layer strips #97356