[Regions] pCorProfilerInfo->GetObjectGeneration may fail when running under USE_REGIONS #55965
Description
This is a bug found when working on the filtering issue.
Problem:
The crux of the issue is that under USE_REGIONS, the GC may use some unseen memory address since the last GC during allocation. In particular, in soh_try_fit, it may use the get_new_region method to acquire a new region, chain it to the end of gen0 and allocate the object there. At that point of time, the s_currentGenerationTable maintained by the profiler is unaware of those new addresses, therefore during the ObjectAllocated callback, GetObjectGeneration for that newly allocated object would fail.
Repro:
The profiler authored for the gcallocate test can be repurposed to reproduce this bug. Here is the modified code. It does 3 different things:
- It changes the flags so that it captures SOH as well
- removed a println, and
- assert in failure.
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
#include "gcallocateprofiler.h"
GUID GCAllocateProfiler::GetClsid()
{
// {55b9554d-6115-45a2-be1e-c80f7fa35369}
GUID clsid = { 0x55b9554d, 0x6115, 0x45a2,{ 0xbe, 0x1e, 0xc8, 0x0f, 0x7f, 0xa3, 0x53, 0x69 } };
return clsid;
}
HRESULT GCAllocateProfiler::Initialize(IUnknown* pICorProfilerInfoUnk)
{
Profiler::Initialize(pICorProfilerInfoUnk);
HRESULT hr = S_OK;
if (FAILED(hr = pCorProfilerInfo->SetEventMask2(COR_PRF_ENABLE_OBJECT_ALLOCATED | COR_PRF_MONITOR_OBJECT_ALLOCATED, COR_PRF_HIGH_BASIC_GC)))
{
printf("FAIL: ICorProfilerInfo::SetEventMask2() failed hr=0x%x", hr);
return hr;
}
return S_OK;
}
HRESULT STDMETHODCALLTYPE GCAllocateProfiler::ObjectAllocated(ObjectID objectId, ClassID classId)
{
COR_PRF_GC_GENERATION_RANGE gen;
HRESULT hr = pCorProfilerInfo->GetObjectGeneration(objectId, &gen);
if (FAILED(hr))
{
assert (false);
printf("GetObjectGeneration failed hr=0x%x\n", hr);
_failures++;
}
else if (gen.generation == COR_PRF_GC_LARGE_OBJECT_HEAP)
{
_gcLOHAllocations++;
}
else if (gen.generation == COR_PRF_GC_PINNED_OBJECT_HEAP)
{
_gcPOHAllocations++;
}
else
{
_failures++;
}
return S_OK;
}
HRESULT GCAllocateProfiler::Shutdown()
{
Profiler::Shutdown();
if (_gcPOHAllocations == 0)
{
printf("There is no POH allocations\n");
}
else if (_gcLOHAllocations == 0)
{
printf("There is no LOH allocations\n");
}
else if (_failures == 0)
{
printf("%d LOH objects allocated\n", (int)_gcLOHAllocations);
printf("%d POH objects allocated\n", (int)_gcPOHAllocations);
printf("PROFILER TEST PASSES\n");
}
fflush(stdout);
return S_OK;
}The bug can then be reproduced by setting these environment,
set CORECLR_ENABLE_PROFILING=1
set CORECLR_PROFILER={55b9554d-6115-45a2-be1e-c80f7fa35369}
set CORECLR_PROFILER_PATH=C:\dev\runtime\artifacts\tests\coreclr\windows.x64.Debug\profiler\gc\gcallocate\Profiler.dll
and run GCPerfSim with these parameters:
c:\dev\runtime\artifacts\tests\coreclr\Windows.x64.Debug\Tests\Core_Root\CoreRun.exe C:\dev\performance\artifacts\bin\GCPerfSim\release\netcoreapp5.0\GCPerfSim.dll -tc 6 -tagb 100.0 -tlgb 2.0 -lohar 0 -pohar 0 -sohsi 10 -lohsi 0 -pohsi 0 -sohsr 100-4000 -lohsr 102400-204800 -pohsr 100-4000 -sohpi 10 -lohpi 0 -sohfi 0 -lohfi 0 -pohfi 0 -allocType reference -testKind time