MacOS arm64 NAOT runtime-async - bad ResumeInfo written (causing failure on StackTraceTests)

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@agocke

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Is the

Fatal error. Invalid Program: attempted to call a UnmanagedCallersOnly method from managed code.

in the log unrelated?

No; what happens is when we return from Foo2 into Foo1, and attempt to run the resumption of Foo1 (which should be the catch handler because Foo2 throws an exception in its finally), the ResumeInfo contains bad addresses (not sure exactly what is in there, but it looks like some flags on the high bits). We set a watchpoint on the second Continuation created for Foo1, and see that the bad data is written shortly before a call to CaptureContinuationContext, and after some adrp arithmetic. The calling of a bad address in DispatchContinuations then surfaces as the UnmanagedCallersOnly error.

Interestingly only the second adrp/add pair is corrupted in the function in the executable. I'm guessing this is some object writer bug. I can reproduce the issue locally in the object file produced by ILC: only the second adrp/add pair looks wrong there too.

@filipnavara

This fixes the issue:

diff --git a/src/coreclr/tools/Common/Compiler/ObjectWriter/MachObjectWriter.cs b/src/coreclr/tools/Common/Compiler/ObjectWriter/MachObjectWriter.cs
index 659c48acda2..f4aac9b81be 100644
--- a/src/coreclr/tools/Common/Compiler/ObjectWriter/MachObjectWriter.cs
+++ b/src/coreclr/tools/Common/Compiler/ObjectWriter/MachObjectWriter.cs
@@ -460,6 +460,11 @@ private protected override void EmitSymbolRangeDefinition(Utf8String rangeNodeNa
                 case IMAGE_REL_BASED_ARM64_PAGEOFFSET_12A:
                 case IMAGE_REL_BASED_ARM64_PAGEOFFSET_12L:
                     // Addend is handled through ARM64_RELOC_ADDEND
+                    fixed (byte* pData = data)
+                    {
+                        addend += Relocation.ReadValue(relocType, pData);
+                        Relocation.WriteValue(relocType, pData, 0);
+                    }
                     break;
 
                 case IMAGE_REL_BASED_RELPTR32:

It is the equivalent of this code that I found in LLVM:

https://github.com/llvm/llvm-project/blob/3a084241248efd7d5259183cffae1d5b7057a54c/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MachObjectWriter.cpp#L355-L382

@filipnavara does this look right?

@filipnavara

@filipnavara does this look right?

At first glance it does.

(I will have a second look tomorrow when I get back to my machine; already OOF today)

It looks like we are not running runtime tests for osx-arm64 in nativeaot-outerloop, otherwise I expect we would have seen the normal async tests failing in #123433.

Fix MachO adrp/add and branch relocations with embedded addend (dotne…

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MacOS arm64 NAOT runtime-async - bad ResumeInfo written (causing failure on StackTraceTests) #124015

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MacOS arm64 NAOT runtime-async - bad ResumeInfo written (causing failure on StackTraceTests) #124015

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dotnet-policy-service commented on Feb 4, 2026

jakobbotsch commented on Feb 4, 2026

rcj1 commented on Feb 4, 2026

jakobbotsch commented on Feb 5, 2026

jakobbotsch commented on Feb 5, 2026

filipnavara commented on Feb 5, 2026

jakobbotsch commented on Feb 5, 2026

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