[release/10.0] Fix removing module from appdomain in DB_IPCE_UNLOAD_MODULE event (#124241)

github-actions[bot] · tommcdon · web-flow · commit 7229c7ce1693 · 2026-02-11T20:45:22.000Z
Backport of #123931 to release/10.0 /cc @hoyosjs @tommcdon ## Customer Impact - [X] Customer reported - [ ] Found internally When loading and unloading an Assembly multiple times in new AssemblyLoadContexts Visual Studio will abruptly end debugging before program completion with the following error: > A fatal error has occurred and debugging needs to be terminated. For more details, please see the Microsoft Help and Support web site. HRESULT=0x80131c36. ErrorCode=0x0. Originally reported via Visual Studio feedback item [Fatal error encountered when debugging .net 10 app using collectible assemblies in VS2026](https://developercommunity.visualstudio.com/t/Fatal-error-encountered-when-debugging-/10982926), then moved to GH issue #123930. ## Regression - [X] Yes - [ ] No Regression from .NET 9, introduced in .NET 10 on #117224 and was a missed case when attempting to address the issue in #118414. ## Testing Validated with customer's reproducible test case on #123930 ## Risk Low. The debugger module caches uses the module as the hash key rather than the assembly. This was a missed case when fixing #118414 where we were still incorrectly using the assembly as the lookup key. Co-authored-by: Tom McDonald <tommcdon@microsoft.com>
diff --git a/src/coreclr/debug/di/module.cpp b/src/coreclr/debug/di/module.cpp
@@ -117,8 +117,8 @@ void DbgAssertModuleDeletedCallback(VMPTR_DomainAssembly vmDomainAssembly, void
 //
 void CordbModule::DbgAssertModuleDeleted()
 {
-    GetProcess()->GetDAC()->EnumerateModulesInAssembly(
-        m_pAssembly->GetDomainAssemblyPtr(),
+    GetProcess()->GetDAC()->EnumerateAssembliesInAppDomain(
+        m_pAppDomain->GetADToken(),
         DbgAssertModuleDeletedCallback,
         this);
 }
diff --git a/src/coreclr/debug/di/process.cpp b/src/coreclr/debug/di/process.cpp
@@ -5225,7 +5225,7 @@ void CordbProcess::RawDispatchEvent(
                 pCallback1->UnloadModule(pAppDomain, module);
             }
 
-            pAppDomain->m_modules.RemoveBase(VmPtrToCookie(pEvent->UnloadModuleData.vmDomainAssembly));
+            pAppDomain->m_modules.RemoveBase(VmPtrToCookie(module->m_vmModule));
         }
         break;
 

Original file line number	Diff line number	Diff line change
`@@ -117,8 +117,8 @@ void DbgAssertModuleDeletedCallback(VMPTR_DomainAssembly vmDomainAssembly, void`
`117`	`117`	`//`
`118`	`118`	`void CordbModule::DbgAssertModuleDeleted()`
`119`	`119`	`{`
`120`		`- GetProcess()->GetDAC()->EnumerateModulesInAssembly(`
`121`		`- m_pAssembly->GetDomainAssemblyPtr(),`
	`120`	`+ GetProcess()->GetDAC()->EnumerateAssembliesInAppDomain(`
	`121`	`+ m_pAppDomain->GetADToken(),`
`122`	`122`	`DbgAssertModuleDeletedCallback,`
`123`	`123`	`this);`
`124`	`124`	`}`
Original file line number	Diff line number	Diff line change
`@@ -5225,7 +5225,7 @@ void CordbProcess::RawDispatchEvent(`
`5225`	`5225`	`pCallback1->UnloadModule(pAppDomain, module);`
`5226`	`5226`	`}`
`5227`	`5227`
`5228`		`- pAppDomain->m_modules.RemoveBase(VmPtrToCookie(pEvent->UnloadModuleData.vmDomainAssembly));`
	`5228`	`+ pAppDomain->m_modules.RemoveBase(VmPtrToCookie(module->m_vmModule));`
`5229`	`5229`	`}`
`5230`	`5230`	`break;`
`5231`	`5231`