[release/9.0] Fix FP state restore on macOS exception forwarding #110163
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…28.2 (#109323) Microsoft.SourceBuild.Intermediate.emsdk , Microsoft.NET.Workload.Emscripten.Current.Manifest-9.0.100 , Microsoft.NET.Workload.Emscripten.Current.Manifest-9.0.100.Transport From Version 9.0.0-rtm.24519.2 -> To Version 9.0.0-rtm.24528.2 Dependency coherency updates runtime.linux-arm64.Microsoft.NETCore.Runtime.JIT.Tools,runtime.linux-x64.Microsoft.NETCore.Runtime.JIT.Tools,runtime.linux-musl-arm64.Microsoft.NETCore.Runtime.JIT.Tools,runtime.linux-musl-x64.Microsoft.NETCore.Runtime.JIT.Tools,runtime.win-arm64.Microsoft.NETCore.Runtime.JIT.Tools,runtime.win-x64.Microsoft.NETCore.Runtime.JIT.Tools,runtime.osx-arm64.Microsoft.NETCore.Runtime.JIT.Tools,runtime.osx-x64.Microsoft.NETCore.Runtime.JIT.Tools,runtime.linux-arm64.Microsoft.NETCore.Runtime.Mono.LLVM.Sdk,runtime.linux-arm64.Microsoft.NETCore.Runtime.Mono.LLVM.Tools,runtime.linux-musl-arm64.Microsoft.NETCore.Runtime.Mono.LLVM.Sdk,runtime.linux-musl-arm64.Microsoft.NETCore.Runtime.Mono.LLVM.Tools,runtime.linux-x64.Microsoft.NETCore.Runtime.Mono.LLVM.Sdk,runtime.linux-x64.Microsoft.NETCore.Runtime.Mono.LLVM.Tools,runtime.linux-musl-x64.Microsoft.NETCore.Runtime.Mono.LLVM.Sdk,runtime.linux-musl-x64.Microsoft.NETCore.Runtime.Mono.LLVM.Tools,runtime.win-x64.Microsoft.NETCore.Runtime.Mono.LLVM.Sdk,runtime.win-x64.Microsoft.NETCore.Runtime.Mono.LLVM.Tools,runtime.osx-arm64.Microsoft.NETCore.Runtime.Mono.LLVM.Sdk,runtime.osx-arm64.Microsoft.NETCore.Runtime.Mono.LLVM.Tools,runtime.osx-x64.Microsoft.NETCore.Runtime.Mono.LLVM.Sdk,runtime.osx-x64.Microsoft.NETCore.Runtime.Mono.LLVM.Tools From Version 19.1.0-alpha.1.24510.5 -> To Version 19.1.0-alpha.1.24519.2 (parent: Microsoft.NET.Workload.Emscripten.Current.Manifest-9.0.100.Transport Co-authored-by: dotnet-maestro[bot] <dotnet-maestro[bot]@users.noreply.github.com>
The change that enabled AVX512 support in the past has introduced a subtle issue in restoring context for forwarding hardware exceptions that occur in 3rd party non-managed code. In that case, the restored floating point state is garbled. The problem is due to the fact that we pass a x86_avx512_state context to the thread_set_state. That context contains a header field describing the format of the context (it can be AVX, AVX512, 32 or 64 bit, ...). That is then followed by the actual context structure. This style of context is identified e.g. by x86_AVX_STATE flavor. The header field contains the specific flavor, which would be x86_AVX_STATE64 or x86_AVX512_STATE64. The thread_set_state uses the flavor to detect whether the context passed to it is this combined one or just x86_AVX_STATE64 or x86_AVX512_STATE64 which doesn't have the header field. The issue was that while we were passing in the combined context, we were passing in the flavor extracted from its header. So the thread_set_state used the header as part of the context. That resulted e.g. in xmm register contents being shifted by 8 bytes, thus garbling the state.
jeffschwMSFT
approved these changes
Nov 25, 2024
VSadov
approved these changes
Nov 25, 2024
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LGTM. Thanks! |
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There are three failing tests on ios, the failure in all cases is unrelated to this change: It is #110395 |
jeffschwMSFT
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Backport of #109458 to release/9.0
/cc @janvorli
Customer Impact
[x] Customer reported
[ ] Found internally
Original issue: #109423
Attempt to load Java VM into .NET process on macOS x64 always crashes due to a problem in hardware exception forwarding from coreclr's exception handling port to Java's exception handling port (or any other registered one).
Regression
[x] Yes
[ ] No
Regression in .NET 9 Preview 6 due to a change to fix AVX512 support on macOS for debugging.
Testing
Testing using a repro provided by the customer and coreclr tests
Risk
Low, fixes an obviously incorrect floating point context restoration in case of hardware exception in external non-.NET code.