Sequencer: crash transforming strips with overwrite enabled #91096

New Issue

Campbell Barton · 2021-09-01T01:15:45+02:00

Campbell Barton commented

2021-09-01 01:15:45 +02:00

Transforming sequences strips with the overwrite option enabled can crash.

Tested with 838b6ec48af6fb767089784193d8525c5f5faf13 (3.0 master).

With this file, in the sequencer view press:

G key.
Type in 654.
Press Enter to confirm.

... if this doesn't crash, press Ctrl-Z and repeat the steps above.

ASAN reports use-after free.

sequencer_overwrite_crash_with_handle.blend

Transforming sequences strips with the overwrite option enabled can crash. Tested with `838b6ec48af6fb767089784193d8525c5f5faf13` (3.0 master). With this file, in the sequencer view press: - `G` key. - Type in `654`. - Press Enter to confirm. ... if this doesn't crash, press Ctrl-Z and repeat the steps above. ASAN reports use-after free. [sequencer_overwrite_crash_with_handle.blend](https://archive.blender.org/developer/F10359142/sequencer_overwrite_crash_with_handle.blend)

Richard Antalik was assigned by Campbell Barton

2021-09-01 01:15:45 +02:00

Campbell Barton commented

2021-09-01 01:15:45 +02:00

Added subscriber: @ideasman42

Campbell Barton changed title from ~~Crash transforming sequence strips with overwrite enabled~~ to Sequencer: crash transforming strips with overwrite enabled

2021-09-01 01:56:53 +02:00

Richard Antalik commented

2021-09-01 02:56:14 +02:00

This is probably cause of different resuls for #91098. Does ASAN give some details like stack trace? AFAIK ASAN is still not functional on windows.

This is probably cause of different resuls for `#91098`. Does ASAN give some details like stack trace? AFAIK ASAN is still not functional on windows.

Campbell Barton commented

2021-09-01 03:39:32 +02:00

Not sure if it's related to #91098 or not, as ASAN would likely crash on bad memory access there too.

Ah, thought ASAN worked everywhere, asan.txt

Recommend spending time to setup ASAN, even on a VM or WSL on Windows, it can help a lot with these kinds of bugs. When enabled during development, they can be caught early.

Not sure if it's related to `#91098` or not, as ASAN would likely crash on bad memory access there too. ---- Ah, thought ASAN worked everywhere, [asan.txt](https://archive.blender.org/developer/F10359328/asan.txt) *Recommend spending time to setup ASAN, even on a VM or WSL on Windows, it can help a lot with these kinds of bugs. When enabled during development, they can be caught early.*

Richard Antalik commented

2021-09-01 04:25:41 +02:00

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

Richard Antalik commented

2021-09-01 04:25:41 +02:00

Thanks for trace. I wanted to switch to Linux due to reasons like these, but I was discouraged, because we need windows developers. As I know myself I wouldn't maintain 2 platforms well and develop only on 1 of them anyway...

I see the issue though - caused by using SEQ_edit_remove_flagged_sequences in 2 areas at the same time. Should be relatively easy to fix on transform side. Not sure if I will be able to eliminate need for SEQ_FLAG_DELETE in SEQ_edit_strip_split. I tried once and failed, but now function is guaranteed to never delete any original strips, it can only create new strips, so perhaps I can do it now.

Thanks for trace. I wanted to switch to Linux due to reasons like these, but I was discouraged, because we need windows developers. As I know myself I wouldn't maintain 2 platforms well and develop only on 1 of them anyway... I see the issue though - caused by using `SEQ_edit_remove_flagged_sequences` in 2 areas at the same time. Should be relatively easy to fix on transform side. Not sure if I will be able to eliminate need for `SEQ_FLAG_DELETE` in `SEQ_edit_strip_split`. I tried once and failed, but now function is guaranteed to never delete any original strips, it can only create new strips, so perhaps I can do it now.

blender-admin commented

2021-10-09 10:11:10 +02:00

This issue was referenced by 2561145da8

This issue was referenced by 2561145da8d1e6db6617fa67c5a306d6e07e34e5

Richard Antalik commented

2021-10-09 10:14:46 +02:00

Changed status from 'Confirmed' to: 'Resolved'

Richard Antalik closed this issue

2021-10-09 10:14:46 +02:00

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Sequencer: crash transforming strips with overwrite enabled #91096