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Fixed

Fixed in 2020.3.37f1, 2021.3.5f1, 2022.1.6f1, 2022.2.0a10

Votes

0

Found in

2020.3.35f1

Issue ID

UUM-2746

Regression

Yes

Memory access violation in LightProbesManager when appending LightProbes objects with overlaps twice

Affects Version

-

Steps to reproduce:
1. Open the attached project (JapanOffice.zip);
2. In the opened popup window for prompting to change Project setting press Cancel button;
3. Ensure that in the Hierarchy there are several scenes loaded additively; if there are none, load those scenes manually;
4. In the Hierarchy select any scene other than the active scene (e.g. NoonB) and double-click on it;
5. Repeat step 4 5-6 times;
6. Enter Play mode.

Expected result: Play mode launches without crashes.
Actual result: Editor crashes

Reproducible with: 2021.2.0b15, 2021.2.4f, 2022.1.0a9, 2022.1.0a16
Not reproducible with: 2019.4.33f1, 2020.3.23f1, 2021.2.0b14, 2022.1.0a8

Notes:
- Reproducible on Windows (by following the repro steps) and macOS (after just opening the repro project);
- The crash might not reproduce every time; if it doesn't try exiting Play mode after step 6 or repeat the initial steps once again with different timings between actions;
- The crash might produce different stack traces on different versions.
- First few lines of a stacktrace:
0x00007ff76b9aed85 (Unity) `anonymous namespace'::CombineMeshFiltersForStaticBatching
0x00007ff76b9ae6f8 (Unity) StaticBatching::CombineAllStaticMeshesInSceneForStaticBatching
0x00007ff76b4174c9 (Unity) StaticBatchingEditorHelper_CUSTOM_CombineAllStaticMeshesForScenePostProcessing
0x000001a845246391 (Mono JIT Code) (wrapper managed-to-native) UnityEditor.StaticBatchingEditorHelper:CombineAllStaticMeshesForScenePostProcessing (ulong)
0x000001a845245983 (Mono JIT Code) UnityEditor.UnityBuildPostprocessor:OnProcessScene

Probable Root Cause:
When reproing this we found what seemed like random callstack at each crash. Further investigation suggests that this is because LightProbesManager#Append() can write beyond the range of its allocated memory (see the memcpy involving m_BakedCoefficients inside Append()). By doing this it effectively caused undefined behaviour (including sometimes crashing the editor).

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