[Bug] Memory corruption in EntityDiffer BlobAsset handling | Official Unity Discord | Page 1

grim lava Feb 18, 2025, 11:50 AM

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EntityDiffer accesses freed memory and can end up adding destroyed blob assets to target world. Patch attached.

📎 fixed_memory_access_violation_in_EntityDiffer_that_can_lead_to_destroyed_BlobAsset_reachin.patch

grim lava Feb 19, 2025, 12:03 PM

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[Bug] Memory corruption in EntityDiffer BlobAsset handling

forest glen Feb 20, 2025, 8:41 PM

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Thank you for the report; I've flagged a teammate to swing by and gather some additional information.

grim lava Feb 21, 2025, 7:54 AM

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Repro:

create a project with com.unity.entities, com.unity.entities.graphics and com.unity.physics
launch the editor with '-debugallocator -systemallocator'
create a subscene and drag a 3D Object -> Cube into it; must run live conversion
scale the object a few times
-> NullReferenceException due to non-allocated memory access in BlobAssetPtr.Hash, called from EntityDiffer.cs:503 (keyValue.Value.Hash)

We encountered this due to the deleted BlobAsset getting readded to the world in some cases.

forest glen Feb 24, 2025, 5:15 PM

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@grim lava Apologies for the bureaucracy, but can you file this as a bug and post the IN-xxx number here once you've got one? (We're already working on it in the meantime, but it's helpful to have a bug ticket to track along the way)

#[Bug] Memory corruption in EntityDiffer BlobAsset handling