Mutating scene objects in frame_change_post causes stochastic render-animation segfault with interface locked #127546

New Issue

Andy-Abate · 2024-09-13T06:34:50+02:00

Andy-Abate commented

2024-09-13 06:34:50 +02:00

System Information
Operating system: Linux-6.8.0-40-generic-x86_64-with-glibc2.35 64 Bits, X11 UI
Graphics card: Mesa Intel(R) Graphics (ADL GT2) Intel 4.6 (Core Profile) Mesa 23.2.1-1ubuntu3.1~22.04.2

Blender Version
Broken: version: 4.2.1 LTS, branch: blender-v4.2-release, commit date: 2024-08-19 11:21, hash: 396f546c9d82
Also broken on the latest 4.2.2 build

Short description of error
Seemingly due to a combination of factors, Blender sees stochastic segfaults when changing the position of scene objects within a frame_change_post callback, even when the interface is locked. I'm aware the docs say to lock the interface, and I have that setting toggled in the scene and I also enable it in the callback.

Exact steps for others to reproduce the error
Run Blender from a terminal to capture output. Open the attached .blend file, run the script, and render the animation. You may need to attempt the render multiple times, but I was able to tune this file such that I get a crash on the first or second attempt (with other configurations of number of boxes and number of iterations, it may take a handful of attempts or even appear to work except for once in 20~30 attempts).

The terminal should show the crash after a randomly-numbered frame (46 for this particular crash):

Append frame 45
Time: 00:00.05 (Saving: 00:00.02)

Append frame 46
Time: 00:00.05 (Saving: 00:00.02)

Writing: /tmp/frame_change_post_dg.crash.txt
Segmentation fault (core dumped)

I only saw it once, but there was one occurrence of "nullptr dealloc" or "nullptr dereference" (I forget which) in the terminal output.

**System Information** Operating system: Linux-6.8.0-40-generic-x86_64-with-glibc2.35 64 Bits, X11 UI Graphics card: Mesa Intel(R) Graphics (ADL GT2) Intel 4.6 (Core Profile) Mesa 23.2.1-1ubuntu3.1~22.04.2 **Blender Version** Broken: version: 4.2.1 LTS, branch: blender-v4.2-release, commit date: 2024-08-19 11:21, hash: `396f546c9d82` Also broken on the latest 4.2.2 build **Short description of error** Seemingly due to a combination of factors, Blender sees stochastic segfaults when changing the position of scene objects within a `frame_change_post` callback, _even when the interface is locked_. I'm aware the docs say to lock the interface, and I have that setting toggled in the scene and I also enable it in the callback. **Exact steps for others to reproduce the error** Run Blender from a terminal to capture output. Open the attached .blend file, run the script, and render the animation. You may need to attempt the render multiple times, but I was able to tune this file such that I get a crash on the first or second attempt (with other configurations of number of boxes and number of iterations, it may take a handful of attempts or even appear to work except for once in 20~30 attempts). The terminal should show the crash after a randomly-numbered frame (46 for this particular crash): ``` Append frame 45 Time: 00:00.05 (Saving: 00:00.02) Append frame 46 Time: 00:00.05 (Saving: 00:00.02) Writing: /tmp/frame_change_post_dg.crash.txt Segmentation fault (core dumped) ``` I only saw it once, but there was one occurrence of "nullptr dealloc" or "nullptr dereference" (I forget which) in the terminal output.

frame_change_post.blend

111 KiB

frame_change_post.crash.txt

1.5 KiB

Andy-Abate added the

labels 2024-09-13 06:34:51 +02:00