From f7e7903105f7df053bf259542553cefc6a9a6b27 Mon Sep 17 00:00:00 2001 From: Nicky Date: Wed, 10 Apr 2024 21:02:40 +0200 Subject: Fix ASAN errors from LLVector4a::memcpyNonAliased16 Found by running with -fsanitze=thread Suggestion to avoid accessing invalid memory: In both cases memory will be allocated by can be accessed beyond bounds. In LLPolyMesh it can be off by at least one (+x%2). Though I am not even sure if even in best case it always will be a multiple of 16. In LLViewerJointMesh::updateFaceData the code tries to account for padding by, but the allocation in LLPolyMeshSharedData::allocateVertexData is done without any padding. Thus the sizes must not match. Replacing the calls with memcpy as a quick fix to see if the error goes away fixed address sanitzer complaining. It is up to debate if memcpy is a good replacement. LLVector4a::memcpyNonAliased16 was invented for performance. But on the other hand one could argue that nowadays every stdlib maintainer will very heavily optmize functions like memcpy themselves and could take advantage of CPU features the old LL implementation does not take into account. AVX comes to mind. In any case did I not measure any of this. --- indra/llappearance/llpolymesh.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'indra/llappearance/llpolymesh.cpp') diff --git a/indra/llappearance/llpolymesh.cpp b/indra/llappearance/llpolymesh.cpp index 97f9ca68b6..6bfb7456e8 100644 --- a/indra/llappearance/llpolymesh.cpp +++ b/indra/llappearance/llpolymesh.cpp @@ -981,7 +981,7 @@ void LLPolyMesh::initializeForMorph() LLVector4a::memcpyNonAliased16((F32*) mScaledNormals, (F32*) mSharedData->mBaseNormals, sizeof(LLVector4a) * mSharedData->mNumVertices); LLVector4a::memcpyNonAliased16((F32*) mBinormals, (F32*) mSharedData->mBaseNormals, sizeof(LLVector4a) * mSharedData->mNumVertices); LLVector4a::memcpyNonAliased16((F32*) mScaledBinormals, (F32*) mSharedData->mBaseNormals, sizeof(LLVector4a) * mSharedData->mNumVertices); - LLVector4a::memcpyNonAliased16((F32*) mTexCoords, (F32*) mSharedData->mTexCoords, sizeof(LLVector2) * (mSharedData->mNumVertices + mSharedData->mNumVertices%2)); + memcpy((F32*) mTexCoords, (F32*) mSharedData->mTexCoords, sizeof(LLVector2) * (mSharedData->mNumVertices)); // allocated in LLPolyMeshSharedData::allocateVertexData for (S32 i = 0; i < mSharedData->mNumVertices; ++i) { -- cgit v1.2.3 From f02a400134d83a12f43151c3dba32732bf88fd8c Mon Sep 17 00:00:00 2001 From: Andrey Lihatskiy Date: Tue, 11 Mar 2025 05:38:26 +0200 Subject: Fix indentations to make pre-commit happy --- indra/llappearance/llpolymesh.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'indra/llappearance/llpolymesh.cpp') diff --git a/indra/llappearance/llpolymesh.cpp b/indra/llappearance/llpolymesh.cpp index 6bfb7456e8..719381b4fc 100644 --- a/indra/llappearance/llpolymesh.cpp +++ b/indra/llappearance/llpolymesh.cpp @@ -981,7 +981,7 @@ void LLPolyMesh::initializeForMorph() LLVector4a::memcpyNonAliased16((F32*) mScaledNormals, (F32*) mSharedData->mBaseNormals, sizeof(LLVector4a) * mSharedData->mNumVertices); LLVector4a::memcpyNonAliased16((F32*) mBinormals, (F32*) mSharedData->mBaseNormals, sizeof(LLVector4a) * mSharedData->mNumVertices); LLVector4a::memcpyNonAliased16((F32*) mScaledBinormals, (F32*) mSharedData->mBaseNormals, sizeof(LLVector4a) * mSharedData->mNumVertices); - memcpy((F32*) mTexCoords, (F32*) mSharedData->mTexCoords, sizeof(LLVector2) * (mSharedData->mNumVertices)); // allocated in LLPolyMeshSharedData::allocateVertexData + memcpy((F32*) mTexCoords, (F32*) mSharedData->mTexCoords, sizeof(LLVector2) * (mSharedData->mNumVertices)); // allocated in LLPolyMeshSharedData::allocateVertexData for (S32 i = 0; i < mSharedData->mNumVertices; ++i) { -- cgit v1.2.3