Imported Upstream version 2.0.0.12082upstream/2.0.0.12082

7 files changed, 544 insertions, 162 deletions

diff --git a/src/debug/createdump/crashinfo.cpp b/src/debug/createdump/crashinfo.cpp
index b825f4d301..edc31616de 100644
--- a/src/debug/createdump/crashinfo.cpp
+++ b/src/debug/createdump/crashinfo.cpp
@@ -89,6 +89,10 @@ CrashInfo::EnumMemoryRegion(
     return S_OK;
 }
 
+//
+// Suspends all the threads and creating a list of them. Should be the first before 
+// gather any info about the process.
+//
 bool 
 CrashInfo::EnumerateAndSuspendThreads()
 {
@@ -134,6 +138,9 @@ CrashInfo::EnumerateAndSuspendThreads()
     return true;
 }
 
+//
+// Gather all the necessary crash dump info.
+//
 bool
 CrashInfo::GatherCrashInfo(const char* programPath, MINIDUMP_TYPE minidumpType)
 {
@@ -168,42 +175,33 @@ CrashInfo::GatherCrashInfo(const char* programPath, MINIDUMP_TYPE minidumpType)
     // If full memory dump, include everything regardless of permissions
     if (minidumpType & MiniDumpWithFullMemory)
     {
-       for (const MemoryRegion& region : m_moduleMappings)
-       {
-            if (ValidRegion(region))
-            {
-                InsertMemoryRegion(region);
-            }
+        for (const MemoryRegion& region : m_moduleMappings)
+        {
+            InsertMemoryBackedRegion(region);
         }
         for (const MemoryRegion& region : m_otherMappings)
         {
-            if (ValidRegion(region))
-            {
-                InsertMemoryRegion(region);
-            }
+            InsertMemoryBackedRegion(region);
         }
     }
-    else
+    // Add all the heap (read/write) memory regions (m_otherMappings contains the heaps)
+    else if (minidumpType & MiniDumpWithPrivateReadWriteMemory)
     {
-        // Add all the heap (read/write) memory regions but not the modules' r/w data segments
-        if (minidumpType & MiniDumpWithPrivateReadWriteMemory)
+        for (const MemoryRegion& region : m_otherMappings)
         {
-            for (const MemoryRegion& region : m_otherMappings)
+            if (region.Permissions() == (PF_R | PF_W))
             {
-                if (region.Permissions() == (PF_R | PF_W))
-                {
-                    if (ValidRegion(region))
-                    {
-                        InsertMemoryRegion(region);
-                    }
-                }
+                InsertMemoryBackedRegion(region);
             }
         }
-        // Gather all the useful memory regions from the DAC
-        if (!EnumerateMemoryRegionsWithDAC(programPath, minidumpType))
-        {
-            return false;
-        }
+    }
+    // Gather all the useful memory regions from the DAC
+    if (!EnumerateMemoryRegionsWithDAC(programPath, minidumpType))
+    {
+        return false;
+    }
+    if ((minidumpType & MiniDumpWithFullMemory) == 0)
+    {
         // Add the thread's stack and some code memory to core
         for (ThreadInfo* thread : m_threads)
         {
@@ -217,6 +215,19 @@ CrashInfo::GatherCrashInfo(const char* programPath, MINIDUMP_TYPE minidumpType)
             thread->GetThreadCode(&start, &size);
             InsertMemoryRegion(start, size);
         }
+        // All the regions added so far has been backed by memory. Now add the rest of 
+        // mappings so the debuggers like lldb see that an address is code (PF_X) even
+        // if it isn't actually in the core dump.
+        for (const MemoryRegion& region : m_moduleMappings)
+        {
+            assert(!region.IsBackedByMemory());
+            InsertMemoryRegion(region);
+        }
+        for (const MemoryRegion& region : m_otherMappings)
+        {
+            assert(!region.IsBackedByMemory());
+            InsertMemoryRegion(region);
+        }
     }
     // Join all adjacent memory regions
     CombineMemoryRegions();
@@ -235,6 +246,9 @@ CrashInfo::ResumeThreads()
     }
 }
 
+//
+// Get the auxv entries to use and add to the core dump
+//
 bool 
 CrashInfo::GetAuxvEntries()
 {
@@ -269,6 +283,9 @@ CrashInfo::GetAuxvEntries()
     return result;
 }
 
+//
+// Get the module mappings for the core dump NT_FILE notes
+//
 bool
 CrashInfo::EnumerateModuleMappings()
 {
@@ -320,30 +337,38 @@ CrashInfo::EnumerateModuleMappings()
         int c = sscanf(line, "%lx-%lx %m[-rwxsp] %lx %*[:0-9a-f] %*d %ms\n", &start, &end, &permissions, &offset, &moduleName);
         if (c == 4 || c == 5)
         {
-            if (linuxGateAddress != nullptr && reinterpret_cast<void*>(start) == linuxGateAddress)
-            {
-                InsertMemoryRegion(start, end - start);
-                free(moduleName);
+            // r = read
+            // w = write
+            // x = execute
+            // s = shared
+            // p = private (copy on write)
+            uint32_t regionFlags = 0;
+            if (strchr(permissions, 'r')) {
+                regionFlags |= PF_R;
             }
-            else {
-                uint32_t permissionFlags = 0;
-                if (strchr(permissions, 'r')) {
-                    permissionFlags |= PF_R;
-                }
-                if (strchr(permissions, 'w')) {
-                    permissionFlags |= PF_W;
-                }
-                if (strchr(permissions, 'x')) {
-                    permissionFlags |= PF_X;
-                }
-                MemoryRegion memoryRegion(permissionFlags, start, end, offset, moduleName);
+            if (strchr(permissions, 'w')) {
+                regionFlags |= PF_W;
+            }
+            if (strchr(permissions, 'x')) {
+                regionFlags |= PF_X;
+            }
+            if (strchr(permissions, 's')) {
+                regionFlags |= MEMORY_REGION_FLAG_SHARED;
+            }
+            if (strchr(permissions, 'p')) {
+                regionFlags |= MEMORY_REGION_FLAG_PRIVATE;
+            }
+            MemoryRegion memoryRegion(regionFlags, start, end, offset, moduleName);
 
-                if (moduleName != nullptr && *moduleName == '/') {
-                    m_moduleMappings.insert(memoryRegion);
-                }
-                else {
-                    m_otherMappings.insert(memoryRegion);
-                }
+            if (moduleName != nullptr && *moduleName == '/') {
+                m_moduleMappings.insert(memoryRegion);
+            }
+            else {
+                m_otherMappings.insert(memoryRegion);
+            }
+            if (linuxGateAddress != nullptr && reinterpret_cast<void*>(start) == linuxGateAddress)
+            {
+                InsertMemoryBackedRegion(memoryRegion);
             }
             free(permissions);
         }
@@ -354,12 +379,12 @@ CrashInfo::EnumerateModuleMappings()
         TRACE("Module mappings:\n");
         for (const MemoryRegion& region : m_moduleMappings)
         {
-            region.Print();
+            region.Trace();
         }
         TRACE("Other mappings:\n");
         for (const MemoryRegion& region : m_otherMappings)
         {
-            region.Print();
+            region.Trace();
         }
     }
 
@@ -369,12 +394,16 @@ CrashInfo::EnumerateModuleMappings()
     return true;
 }
 
+//
+// All the shared (native) module info to the core dump
+//
 bool
 CrashInfo::GetDSOInfo()
 {
     Phdr* phdrAddr = reinterpret_cast<Phdr*>(m_auxvValues[AT_PHDR]);
     int phnum = m_auxvValues[AT_PHNUM];
     assert(m_auxvValues[AT_PHENT] == sizeof(Phdr));
+    assert(phnum != PN_XNUM);
 
     if (phnum <= 0 || phdrAddr == nullptr) {
         return false;
@@ -387,6 +416,7 @@ CrashInfo::GetDSOInfo()
     {
         Phdr ph;
         if (!ReadMemory(phdrAddr, &ph, sizeof(ph))) {
+            fprintf(stderr, "ReadMemory(%p, %lx) phdr FAILED\n", phdrAddr, sizeof(ph));
             return false;
         }
         TRACE("DSO: phdr %p type %d (%x) vaddr %016lx memsz %016lx offset %016lx\n", 
@@ -396,7 +426,7 @@ CrashInfo::GetDSOInfo()
         {
             dynamicAddr = reinterpret_cast<ElfW(Dyn)*>(ph.p_vaddr);
         }
-        else if (ph.p_type == PT_GNU_EH_FRAME)
+        else if (ph.p_type == PT_NOTE || ph.p_type == PT_GNU_EH_FRAME)
         {
             if (ph.p_vaddr != 0 && ph.p_memsz != 0)
             {
@@ -414,6 +444,7 @@ CrashInfo::GetDSOInfo()
     for (;;) {
         ElfW(Dyn) dyn;
         if (!ReadMemory(dynamicAddr, &dyn, sizeof(dyn))) {
+            fprintf(stderr, "ReadMemory(%p, %lx) dyn FAILED\n", dynamicAddr, sizeof(dyn));
             return false;
         }
         TRACE("DSO: dyn %p tag %ld (%lx) d_ptr %016lx\n", dynamicAddr, dyn.d_tag, dyn.d_tag, dyn.d_un.d_ptr);
@@ -430,6 +461,7 @@ CrashInfo::GetDSOInfo()
     TRACE("DSO: rdebugAddr %p\n", rdebugAddr);
     struct r_debug debugEntry;
     if (!ReadMemory(rdebugAddr, &debugEntry, sizeof(debugEntry))) {
+        fprintf(stderr, "ReadMemory(%p, %lx) r_debug FAILED\n", rdebugAddr, sizeof(debugEntry));
         return false;
     }
 
@@ -438,8 +470,10 @@ CrashInfo::GetDSOInfo()
     for (struct link_map* linkMapAddr = debugEntry.r_map; linkMapAddr != nullptr;) {
         struct link_map map;
         if (!ReadMemory(linkMapAddr, &map, sizeof(map))) {
+            fprintf(stderr, "ReadMemory(%p, %lx) link_map FAILED\n", linkMapAddr, sizeof(map));
             return false;
         }
+        // Read the module's name and make sure the memory is added to the core dump
         int i = 0;
         if (map.l_name != nullptr) {
             for (; i < PATH_MAX; i++)
@@ -454,18 +488,134 @@ CrashInfo::GetDSOInfo()
             }
         }
         moduleName[i] = '\0';
-        TRACE("DSO: link_map entry %p l_ld %p l_addr %lx %s\n", linkMapAddr, map.l_ld, map.l_addr, (char*)moduleName);
+        TRACE("\nDSO: link_map entry %p l_ld %p l_addr (Ehdr) %lx %s\n", linkMapAddr, map.l_ld, map.l_addr, (char*)moduleName);
+
+        // Read the ELF header and info adding it to the core dump
+        if (!GetELFInfo(map.l_addr)) {
+            return false;
+        }
         linkMapAddr = map.l_next;
     }
 
     return true;
 }
 
+inline bool
+NameCompare(const char* name, const char* sectionName)
+{
+    return strncmp(name, sectionName, strlen(sectionName) + 1) == 0;
+}
+
+//
+// Add all the necessary ELF headers to the core dump
+//
+bool
+CrashInfo::GetELFInfo(uint64_t baseAddress)
+{
+    if (baseAddress == 0) {
+        return true;
+    }
+    Ehdr ehdr;
+    if (!ReadMemory((void*)baseAddress, &ehdr, sizeof(ehdr))) {
+        fprintf(stderr, "ReadMemory(%p, %lx) ehdr FAILED\n", (void*)baseAddress, sizeof(ehdr));
+        return false;
+    }
+    int phnum = ehdr.e_phnum;
+    int shnum = ehdr.e_shnum;
+    assert(phnum != PN_XNUM);
+    assert(shnum != SHN_XINDEX);
+    assert(ehdr.e_shstrndx != SHN_XINDEX);
+    assert(ehdr.e_phentsize == sizeof(Phdr));
+    assert(ehdr.e_shentsize == sizeof(Shdr));
+    assert(ehdr.e_ident[EI_CLASS] == ELFCLASS64);
+    assert(ehdr.e_ident[EI_DATA] == ELFDATA2LSB);
+
+    TRACE("ELF: type %d mach 0x%x ver %d flags 0x%x phnum %d phoff %016lx phentsize 0x%02x shnum %d shoff %016lx shentsize 0x%02x shstrndx %d\n",
+        ehdr.e_type, ehdr.e_machine, ehdr.e_version, ehdr.e_flags, phnum, ehdr.e_phoff, ehdr.e_phentsize, shnum, ehdr.e_shoff, ehdr.e_shentsize, ehdr.e_shstrndx);
+
+    if (ehdr.e_phoff != 0 && phnum > 0)
+    {
+        Phdr* phdrAddr = reinterpret_cast<Phdr*>(baseAddress + ehdr.e_phoff);
+
+        // Add the program headers and search for the module's note and unwind info segments
+        for (int i = 0; i < phnum; i++, phdrAddr++)
+        {
+            Phdr ph;
+            if (!ReadMemory(phdrAddr, &ph, sizeof(ph))) {
+                fprintf(stderr, "ReadMemory(%p, %lx) phdr FAILED\n", phdrAddr, sizeof(ph));
+                return false;
+            }
+            TRACE("ELF: phdr %p type %d (%x) vaddr %016lx memsz %016lx paddr %016lx filesz %016lx offset %016lx align %016lx\n",
+                phdrAddr, ph.p_type, ph.p_type, ph.p_vaddr, ph.p_memsz, ph.p_paddr, ph.p_filesz, ph.p_offset, ph.p_align);
+
+            if (ph.p_type == PT_DYNAMIC || ph.p_type == PT_NOTE || ph.p_type == PT_GNU_EH_FRAME)
+            {
+                if (ph.p_vaddr != 0 && ph.p_memsz != 0)
+                {
+                    InsertMemoryRegion(baseAddress + ph.p_vaddr, ph.p_memsz);
+                }
+            }
+        }
+    }
+
+    // Skip the "interpreter" module i.e. /lib64/ld-linux-x86-64.so.2 or ld-2.19.so. The in-memory section headers are 
+    // not valid. Ignore all failures too because on debug builds of coreclr, the section headers are not in valid memory.
+    if (baseAddress != m_auxvValues[AT_BASE] && ehdr.e_shoff != 0 && shnum > 0 && ehdr.e_shstrndx != SHN_UNDEF)
+    {
+        Shdr* shdrAddr = reinterpret_cast<Shdr*>(baseAddress + ehdr.e_shoff);
+
+        // Get the string table section header
+        Shdr stringTableSectionHeader;
+        if (!ReadMemory(shdrAddr + ehdr.e_shstrndx, &stringTableSectionHeader, sizeof(stringTableSectionHeader))) {
+            TRACE("ELF: %2d shdr %p ReadMemory string table section header FAILED\n", ehdr.e_shstrndx, shdrAddr + ehdr.e_shstrndx);
+            return true;
+        }
+        // Get the string table
+        ArrayHolder<char> stringTable = new char[stringTableSectionHeader.sh_size];
+        if (!ReadMemory((void*)(baseAddress + stringTableSectionHeader.sh_offset), stringTable.GetPtr(), stringTableSectionHeader.sh_size)) {
+            TRACE("ELF: %2d shdr %p ReadMemory string table FAILED\n", ehdr.e_shstrndx, (void*)(baseAddress + stringTableSectionHeader.sh_offset));
+            return true;
+        }
+        // Add the section headers to the core dump
+        for (int sectionIndex = 0; sectionIndex < shnum; sectionIndex++, shdrAddr++)
+        {
+            Shdr sh;
+            if (!ReadMemory(shdrAddr, &sh, sizeof(sh))) {
+                TRACE("ELF: %2d shdr %p ReadMemory FAILED\n", sectionIndex, shdrAddr);
+                return true;
+            }
+            TRACE("ELF: %2d shdr %p type %2d (%x) addr %016lx offset %016lx size %016lx link %08x info %08x name %4d %s\n",
+                sectionIndex, shdrAddr, sh.sh_type, sh.sh_type, sh.sh_addr, sh.sh_offset, sh.sh_size, sh.sh_link, sh.sh_info, sh.sh_name, &stringTable[sh.sh_name]);
+
+            if (sh.sh_name != SHN_UNDEF && sh.sh_offset > 0 && sh.sh_size > 0) {
+                char* name = &stringTable[sh.sh_name];
+
+                // Add the .eh_frame/.eh_frame_hdr unwind info to the core dump
+                if (NameCompare(name, ".eh_frame") ||
+                    NameCompare(name, ".eh_frame_hdr") ||
+                    NameCompare(name, ".note.gnu.build-id") ||
+                    NameCompare(name, ".note.gnu.ABI-tag") ||
+                    NameCompare(name, ".gnu_debuglink"))
+                {
+                    TRACE("ELF: %s %p size %016lx\n", name, (void*)(baseAddress + sh.sh_offset), sh.sh_size);
+                    InsertMemoryRegion(baseAddress + sh.sh_offset, sh.sh_size);
+                }
+            }
+        }
+    }
+
+    return true;
+}
+
+//
+// Enumerate all the memory regions using the DAC memory region support given a minidump type
+//
 bool
 CrashInfo::EnumerateMemoryRegionsWithDAC(const char* programPath, MINIDUMP_TYPE minidumpType)
 {
     PFN_CLRDataCreateInstance pfnCLRDataCreateInstance = nullptr;
-    ICLRDataEnumMemoryRegions *clrDataEnumRegions = nullptr;
+    ICLRDataEnumMemoryRegions* clrDataEnumRegions = nullptr;
+    IXCLRDataProcess* clrDataProcess = nullptr;
     HMODULE hdac = nullptr;
     HRESULT hr = S_OK;
     bool result = false;
@@ -475,7 +625,7 @@ CrashInfo::EnumerateMemoryRegionsWithDAC(const char* programPath, MINIDUMP_TYPE
     dacPath.append(programPath);
     dacPath.append("/");
     dacPath.append(MAKEDLLNAME_A("mscordaccore"));
-    
+
     // Load and initialize the DAC
     hdac = LoadLibraryA(dacPath.c_str());
     if (hdac == nullptr)
@@ -489,17 +639,30 @@ CrashInfo::EnumerateMemoryRegionsWithDAC(const char* programPath, MINIDUMP_TYPE
         fprintf(stderr, "GetProcAddress(CLRDataCreateInstance) FAILED %d\n", GetLastError());
         goto exit;
     }
-    hr = pfnCLRDataCreateInstance(__uuidof(ICLRDataEnumMemoryRegions), m_dataTarget, (void**)&clrDataEnumRegions);
+    if ((minidumpType & MiniDumpWithFullMemory) == 0)
+    {
+        hr = pfnCLRDataCreateInstance(__uuidof(ICLRDataEnumMemoryRegions), m_dataTarget, (void**)&clrDataEnumRegions);
+        if (FAILED(hr))
+        {
+            fprintf(stderr, "CLRDataCreateInstance(ICLRDataEnumMemoryRegions) FAILED %08x\n", hr);
+            goto exit;
+        }
+        // Calls CrashInfo::EnumMemoryRegion for each memory region found by the DAC
+        hr = clrDataEnumRegions->EnumMemoryRegions(this, minidumpType, CLRDATA_ENUM_MEM_DEFAULT);
+        if (FAILED(hr))
+        {
+            fprintf(stderr, "EnumMemoryRegions FAILED %08x\n", hr);
+            goto exit;
+        }
+    }
+    hr = pfnCLRDataCreateInstance(__uuidof(IXCLRDataProcess), m_dataTarget, (void**)&clrDataProcess);
     if (FAILED(hr))
     {
-        fprintf(stderr, "CLRDataCreateInstance(ICLRDataEnumMemoryRegions) FAILED %08x\n", hr);
+        fprintf(stderr, "CLRDataCreateInstance(IXCLRDataProcess) FAILED %08x\n", hr);
         goto exit;
     }
-    // Calls CrashInfo::EnumMemoryRegion for each memory region found by the DAC
-    hr = clrDataEnumRegions->EnumMemoryRegions(this, minidumpType, CLRDATA_ENUM_MEM_DEFAULT);
-    if (FAILED(hr))
+    if (!EnumerateManagedModules(clrDataProcess))
     {
-        fprintf(stderr, "EnumMemoryRegions FAILED %08x\n", hr);
         goto exit;
     }
     result = true;
@@ -508,6 +671,10 @@ exit:
     {
         clrDataEnumRegions->Release();
     }
+    if (clrDataProcess != nullptr)
+    {
+        clrDataProcess->Release();
+    }
     if (hdac != nullptr)
     {
         FreeLibrary(hdac);
@@ -516,6 +683,104 @@ exit:
 }
 
 //
+// Enumerate all the managed modules and replace the module 
+// mapping with the module name found.
+//
+bool
+CrashInfo::EnumerateManagedModules(IXCLRDataProcess* clrDataProcess)
+{
+    IXCLRDataModule* clrDataModule = nullptr;
+    CLRDATA_ENUM enumModules = 0;
+    HRESULT hr = S_OK;
+
+    if (FAILED(hr = clrDataProcess->StartEnumModules(&enumModules))) {
+        fprintf(stderr, "StartEnumModules FAILED %08x\n", hr);
+        return false;
+    }
+    while ((hr = clrDataProcess->EnumModule(&enumModules, &clrDataModule)) == S_OK)
+    {
+        DacpGetModuleData moduleData;
+        if (SUCCEEDED(hr = moduleData.Request(clrDataModule)))
+        {
+            TRACE("MODULE: %016lx dyn %d inmem %d file %d pe %016lx pdb %016lx", moduleData.LoadedPEAddress, moduleData.IsDynamic, 
+                moduleData.IsInMemory, moduleData.IsFileLayout, moduleData.PEFile, moduleData.InMemoryPdbAddress);
+
+            if (!moduleData.IsDynamic && moduleData.LoadedPEAddress != 0)
+            {
+                ArrayHolder<WCHAR> wszUnicodeName = new WCHAR[MAX_LONGPATH + 1];
+                if (SUCCEEDED(hr = clrDataModule->GetFileName(MAX_LONGPATH, NULL, wszUnicodeName)))
+                {
+                    char* pszName = (char*)malloc(MAX_LONGPATH + 1);
+                    if (pszName == nullptr) {
+                        fprintf(stderr, "Allocating module name FAILED\n");
+                        return false;
+                    }
+                    sprintf_s(pszName, MAX_LONGPATH, "%S", (WCHAR*)wszUnicodeName);
+                    TRACE(" %s\n", pszName);
+
+                    // Change the module mapping name
+                    ReplaceModuleMapping(moduleData.LoadedPEAddress, pszName);
+                }
+                else {
+                    TRACE("\nModule.GetFileName FAILED %08x\n", hr);
+                }
+            }
+            else {
+                TRACE("\n");
+            }
+        }
+        else {
+            TRACE("moduleData.Request FAILED %08x\n", hr);
+        }
+        if (clrDataModule != nullptr) {
+            clrDataModule->Release();
+        }
+    }
+    if (enumModules != 0) {
+        clrDataProcess->EndEnumModules(enumModules);
+    }
+    return true;
+}
+
+//
+// Replace an existing module mapping with one with a different name.
+//
+void
+CrashInfo::ReplaceModuleMapping(CLRDATA_ADDRESS baseAddress, const char* pszName)
+{
+    // Add or change the module mapping for this PE image. The managed assembly images are
+    // already in the module mappings list but in .NET 2.0 they have the name "/dev/zero".
+    MemoryRegion region(PF_R | PF_W | PF_X, baseAddress, baseAddress + PAGE_SIZE, 0, pszName);
+    const auto& found = m_moduleMappings.find(region);
+    if (found == m_moduleMappings.end())
+    {
+        m_moduleMappings.insert(region);
+
+        if (g_diagnostics) {
+            TRACE("MODULE: ADD ");
+            region.Trace();
+        }
+    }
+    else
+    {
+        // Create the new memory region with the managed assembly name.
+        MemoryRegion newRegion(*found, pszName);
+
+        // Remove and cleanup the old one
+        m_moduleMappings.erase(found);
+        const_cast<MemoryRegion&>(*found).Cleanup();
+
+        // Add the new memory region
+        m_moduleMappings.insert(newRegion);
+
+        if (g_diagnostics) {
+            TRACE("MODULE: REPLACE ");
+            newRegion.Trace();
+        }
+    }
+}
+
+//
 // ReadMemory from target and add to memory regions list
 //
 bool
@@ -524,7 +789,6 @@ CrashInfo::ReadMemory(void* address, void* buffer, size_t size)
     uint32_t read = 0;
     if (FAILED(m_dataTarget->ReadVirtual(reinterpret_cast<CLRDATA_ADDRESS>(address), reinterpret_cast<PBYTE>(buffer), size, &read)))
     {
-        fprintf(stderr, "ReadMemory(%p, %lx) FAILED\n", address, size);
         return false;
     }
     InsertMemoryRegion(reinterpret_cast<uint64_t>(address), size);
@@ -538,6 +802,8 @@ CrashInfo::ReadMemory(void* address, void* buffer, size_t size)
 void
 CrashInfo::InsertMemoryRegion(uint64_t address, size_t size)
 {
+    assert(size < UINT_MAX);
+
     // Round to page boundary
     uint64_t start = address & PAGE_MASK;
     assert(start > 0);
@@ -546,8 +812,16 @@ CrashInfo::InsertMemoryRegion(uint64_t address, size_t size)
     uint64_t end = ((address + size) + (PAGE_SIZE - 1)) & PAGE_MASK;
     assert(end > 0);
 
-    MemoryRegion region(start, end);
-    InsertMemoryRegion(region);
+    InsertMemoryRegion(MemoryRegion(GetMemoryRegionFlags(start) | MEMORY_REGION_FLAG_MEMORY_BACKED, start, end));
+}
+
+//
+// Adds a memory backed flagged copy of the memory region. The file name is not preserved.
+//
+void
+CrashInfo::InsertMemoryBackedRegion(const MemoryRegion& region)
+{
+    InsertMemoryRegion(MemoryRegion(region, region.Flags() | MEMORY_REGION_FLAG_MEMORY_BACKED));
 }
 
 //
@@ -556,52 +830,88 @@ CrashInfo::InsertMemoryRegion(uint64_t address, size_t size)
 void
 CrashInfo::InsertMemoryRegion(const MemoryRegion& region)
 {
-    // First check if the full memory region can be added without conflicts
+    // First check if the full memory region can be added without conflicts and is fully valid.
     const auto& found = m_memoryRegions.find(region);
     if (found == m_memoryRegions.end())
     {
-        // Add full memory region
-        m_memoryRegions.insert(region);
+        // If the region is valid, add the full memory region
+        if (ValidRegion(region)) {
+            m_memoryRegions.insert(region);
+            return;
+        }
     }
     else
     {
-        // The memory region is not wholely contained in region found
-        if (!found->Contains(region))
-        {
-            uint64_t start = region.StartAddress();
+        // If the memory region is wholly contained in region found and both have the 
+        // same backed by memory state, we're done.
+        if (found->Contains(region) && (found->IsBackedByMemory() == region.IsBackedByMemory())) {
+            return;
+        }
+    }
+    // Either part of the region was invalid, part of it hasn't been added or the backed
+    // by memory state is different.
+    uint64_t start = region.StartAddress();
 
-            // The region overlaps/conflicts with one already in the set so 
-            // add one page at a time to avoid the overlapping pages.
-            uint64_t numberPages = region.Size() >> PAGE_SHIFT;
+    // The region overlaps/conflicts with one already in the set so add one page at a 
+    // time to avoid the overlapping pages.
+    uint64_t numberPages = region.Size() >> PAGE_SHIFT;
 
-            for (int p = 0; p < numberPages; p++, start += PAGE_SIZE)
-            {
-                MemoryRegion memoryRegionPage(start, start + PAGE_SIZE);
+    for (int p = 0; p < numberPages; p++, start += PAGE_SIZE)
+    {
+        MemoryRegion memoryRegionPage(region.Flags(), start, start + PAGE_SIZE);
 
-                const auto& found = m_memoryRegions.find(memoryRegionPage);
-                if (found == m_memoryRegions.end())
-                {
-                    m_memoryRegions.insert(memoryRegionPage);
-                }
+        const auto& found = m_memoryRegions.find(memoryRegionPage);
+        if (found == m_memoryRegions.end())
+        {
+            // All the single pages added here will be combined in CombineMemoryRegions()
+            if (ValidRegion(memoryRegionPage)) {
+                m_memoryRegions.insert(memoryRegionPage);
             }
         }
+        else {
+            assert(found->IsBackedByMemory() || !region.IsBackedByMemory());
+        }
     }
 }
 
+//
+// Get the memory region flags for a start address
+//
+uint32_t 
+CrashInfo::GetMemoryRegionFlags(uint64_t start)
+{
+    const MemoryRegion* region = SearchMemoryRegions(m_moduleMappings, start);
+    if (region != nullptr) {
+        return region->Flags();
+    }
+    region = SearchMemoryRegions(m_otherMappings, start);
+    if (region != nullptr) {
+        return region->Flags();
+    }
+    TRACE("GetMemoryRegionFlags: FAILED\n");
+    return PF_R | PF_W | PF_X;
+}
+
+//
+// Validates a memory region
+//
 bool
 CrashInfo::ValidRegion(const MemoryRegion& region)
 {
-    uint64_t start = region.StartAddress();
-    uint64_t numberPages = region.Size() >> PAGE_SHIFT;
-
-    for (int p = 0; p < numberPages; p++, start += PAGE_SIZE)
+    if (region.IsBackedByMemory())
     {
-        BYTE buffer[1];
-        uint32_t read;
+        uint64_t start = region.StartAddress();
+        uint64_t numberPages = region.Size() >> PAGE_SHIFT;
 
-        if (FAILED(m_dataTarget->ReadVirtual(start, buffer, 1, &read)))
+        for (int p = 0; p < numberPages; p++, start += PAGE_SIZE)
         {
-            return false;
+            BYTE buffer[1];
+            uint32_t read;
+
+            if (FAILED(m_dataTarget->ReadVirtual(start, buffer, 1, &read)))
+            {
+                return false;
+            }
         }
     }
     return true;
@@ -617,28 +927,34 @@ CrashInfo::CombineMemoryRegions()
 
     std::set<MemoryRegion> memoryRegionsNew;
 
+    // MEMORY_REGION_FLAG_SHARED and MEMORY_REGION_FLAG_PRIVATE are internal flags that 
+    // don't affect the core dump so ignore them when comparing the flags.
+    uint32_t flags = m_memoryRegions.begin()->Flags() & (MEMORY_REGION_FLAG_MEMORY_BACKED | MEMORY_REGION_FLAG_PERMISSIONS_MASK);
     uint64_t start = m_memoryRegions.begin()->StartAddress();
     uint64_t end = start;
 
     for (const MemoryRegion& region : m_memoryRegions)
     {
-        if (end == region.StartAddress())
+        // To combine a region it needs to be contiguous, same permissions and memory backed flag.
+        if ((end == region.StartAddress()) && 
+            (flags == (region.Flags() & (MEMORY_REGION_FLAG_MEMORY_BACKED | MEMORY_REGION_FLAG_PERMISSIONS_MASK))))
         {
             end = region.EndAddress();
         }
         else
         {
-            MemoryRegion memoryRegion(start, end);
+            MemoryRegion memoryRegion(flags, start, end);
             assert(memoryRegionsNew.find(memoryRegion) == memoryRegionsNew.end());
             memoryRegionsNew.insert(memoryRegion);
 
+            flags = region.Flags() & (MEMORY_REGION_FLAG_MEMORY_BACKED | MEMORY_REGION_FLAG_PERMISSIONS_MASK);
             start = region.StartAddress();
             end = region.EndAddress();
         }
     }
 
     assert(start != end);
-    MemoryRegion memoryRegion(start, end);
+    MemoryRegion memoryRegion(flags, start, end);
     assert(memoryRegionsNew.find(memoryRegion) == memoryRegionsNew.end());
     memoryRegionsNew.insert(memoryRegion);
 
@@ -649,11 +965,31 @@ CrashInfo::CombineMemoryRegions()
         TRACE("Memory Regions:\n");
         for (const MemoryRegion& region : m_memoryRegions)
         {
-            region.Print();
+            region.Trace();
+        }
+    }
+}
+
+//
+// Searches for a memory region given an address.
+//
+const MemoryRegion* 
+CrashInfo::SearchMemoryRegions(const std::set<MemoryRegion>& regions, uint64_t start)
+{
+    std::set<MemoryRegion>::iterator found = regions.find(MemoryRegion(0, start, start + PAGE_SIZE));
+    for (; found != regions.end(); found++)
+    {
+        if (start >= found->StartAddress() && start < found->EndAddress())
+        {
+            return &*found;
         }
     }
+	return nullptr;
 }
 
+//
+// Get the process or thread status
+//
 bool
 CrashInfo::GetStatus(pid_t pid, pid_t* ppid, pid_t* tgid, char** name)
 {
diff --git a/src/debug/createdump/crashinfo.h b/src/debug/createdump/crashinfo.h
index 914a88e8dd..43e82691aa 100644
--- a/src/debug/createdump/crashinfo.h
+++ b/src/debug/createdump/crashinfo.h
@@ -38,6 +38,7 @@ public:
     bool GatherCrashInfo(const char* programPath, MINIDUMP_TYPE minidumpType);
     void ResumeThreads();
     static bool GetStatus(pid_t pid, pid_t* ppid, pid_t* tgid, char** name);
+    static const MemoryRegion* SearchMemoryRegions(const std::set<MemoryRegion>& regions, uint64_t start);
 
     const pid_t Pid() const { return m_pid; }
     const pid_t Ppid() const { return m_ppid; }
@@ -46,9 +47,9 @@ public:
     ICLRDataTarget* DataTarget() const { return m_dataTarget; }
 
     const std::vector<ThreadInfo*> Threads() const { return m_threads; }
-    const std::set<MemoryRegion> ModuleMappings()  const { return m_moduleMappings; }
-    const std::set<MemoryRegion> OtherMappings()  const { return m_otherMappings; }
-    const std::set<MemoryRegion> MemoryRegions()  const { return m_memoryRegions; }
+    const std::set<MemoryRegion> ModuleMappings() const { return m_moduleMappings; }
+    const std::set<MemoryRegion> OtherMappings() const { return m_otherMappings; }
+    const std::set<MemoryRegion> MemoryRegions() const { return m_memoryRegions; }
     const std::vector<elf_aux_entry> AuxvEntries() const { return m_auxvEntries; }
     const size_t GetAuxvSize() const { return m_auxvEntries.size() * sizeof(elf_aux_entry); }
 
@@ -58,18 +59,21 @@ public:
     STDMETHOD_(ULONG, Release)();
 
     // ICLRDataEnumMemoryRegionsCallback
-    virtual HRESULT STDMETHODCALLTYPE EnumMemoryRegion( 
-        /* [in] */ CLRDATA_ADDRESS address,
-        /* [in] */ ULONG32 size);
+    virtual HRESULT STDMETHODCALLTYPE EnumMemoryRegion(/* [in] */ CLRDATA_ADDRESS address, /* [in] */ ULONG32 size);
 
 private:
     bool GetAuxvEntries();
     bool EnumerateModuleMappings();
     bool GetDSOInfo();
+    bool GetELFInfo(uint64_t baseAddress);
     bool EnumerateMemoryRegionsWithDAC(const char* programPath, MINIDUMP_TYPE minidumpType);
+    bool EnumerateManagedModules(IXCLRDataProcess* clrDataProcess);
+    void ReplaceModuleMapping(CLRDATA_ADDRESS baseAddress, const char* pszName);
     bool ReadMemory(void* address, void* buffer, size_t size);
+    void InsertMemoryBackedRegion(const MemoryRegion& region);
     void InsertMemoryRegion(uint64_t address, size_t size);
     void InsertMemoryRegion(const MemoryRegion& region);
+    uint32_t GetMemoryRegionFlags(uint64_t start);
     bool ValidRegion(const MemoryRegion& region);
     void CombineMemoryRegions();
 };
diff --git a/src/debug/createdump/createdump.h b/src/debug/createdump/createdump.h
index 38c3525f34..6f72f0e955 100644
--- a/src/debug/createdump/createdump.h
+++ b/src/debug/createdump/createdump.h
@@ -33,6 +33,8 @@ extern bool g_diagnostics;
 #include <xcordebug.h>
 #include <mscoree.h>
 #include <dumpcommon.h>
+typedef int T_CONTEXT;
+#include <dacprivate.h>
 #include <arrayholder.h>
 #include <releaseholder.h>
 #include <unistd.h>
@@ -54,4 +56,4 @@ extern bool g_diagnostics;
 #include "threadinfo.h"
 #include "memoryregion.h"
 #include "crashinfo.h"
-#include "dumpwriter.h"
\ No newline at end of file
+#include "dumpwriter.h"
diff --git a/src/debug/createdump/dumpwriter.cpp b/src/debug/createdump/dumpwriter.cpp
index 69f0ece8af..06c5b96d01 100644
--- a/src/debug/createdump/dumpwriter.cpp
+++ b/src/debug/createdump/dumpwriter.cpp
@@ -91,14 +91,9 @@ DumpWriter::WriteDump()
     ehdr.e_ident[1] = ELFMAG1;
     ehdr.e_ident[2] = ELFMAG2;
     ehdr.e_ident[3] = ELFMAG3;
-    ehdr.e_ident[4] = ELF_CLASS;
-
-    // Note: The sex is the current system running minidump-2-core
-    //       Big or Little endian.  This means you have to create
-    //       the core (minidump-2-core) on the system that matches
-    //       your intent to debug properly.
-    ehdr.e_ident[5] = sex() ? ELFDATA2MSB : ELFDATA2LSB;
-    ehdr.e_ident[6] = EV_CURRENT;
+    ehdr.e_ident[EI_CLASS] = ELF_CLASS;
+    ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
+    ehdr.e_ident[EI_VERSION] = EV_CURRENT;
     ehdr.e_ident[EI_OSABI] = ELFOSABI_LINUX;
 
     ehdr.e_type = ET_CORE;
@@ -180,9 +175,17 @@ DumpWriter::WriteDump()
         phdr.p_vaddr = memoryRegion.StartAddress();
         phdr.p_memsz = memoryRegion.Size();
 
-        offset += filesz;
-        phdr.p_filesz = filesz = memoryRegion.Size();
-        phdr.p_offset = offset;
+        if (memoryRegion.IsBackedByMemory())
+        {
+            offset += filesz;
+            phdr.p_filesz = filesz = memoryRegion.Size();
+            phdr.p_offset = offset;
+        }
+        else 
+        {
+            phdr.p_filesz = 0;
+            phdr.p_offset = 0;
+        }
 
         if (!WriteData(&phdr, sizeof(phdr))) {
             return false;
@@ -230,26 +233,30 @@ DumpWriter::WriteDump()
     uint64_t total = 0;
     for (const MemoryRegion& memoryRegion : m_crashInfo.MemoryRegions())
     {
-        uint32_t size = memoryRegion.Size();
-        uint64_t address = memoryRegion.StartAddress();
-        total += size;
-
-        while (size > 0)
+        // Only write the regions that are backed by memory
+        if (memoryRegion.IsBackedByMemory())
         {
-            uint32_t bytesToRead = std::min(size, (uint32_t)sizeof(m_tempBuffer));
-            uint32_t read = 0;
-
-            if (FAILED(m_crashInfo.DataTarget()->ReadVirtual(address, m_tempBuffer, bytesToRead, &read))) {
-                fprintf(stderr, "ReadVirtual(%016lx, %08x) FAILED\n", address, bytesToRead);
-                return false;
-            }
-
-            if (!WriteData(m_tempBuffer, read)) {
-                return false;
+            uint32_t size = memoryRegion.Size();
+            uint64_t address = memoryRegion.StartAddress();
+            total += size;
+
+            while (size > 0)
+            {
+                uint32_t bytesToRead = std::min(size, (uint32_t)sizeof(m_tempBuffer));
+                uint32_t read = 0;
+
+                if (FAILED(m_crashInfo.DataTarget()->ReadVirtual(address, m_tempBuffer, bytesToRead, &read))) {
+                    fprintf(stderr, "ReadVirtual(%016lx, %08x) FAILED\n", address, bytesToRead);
+                    return false;
+                }
+
+                if (!WriteData(m_tempBuffer, read)) {
+                    return false;
+                }
+
+                address += read;
+                size -= read;
             }
-
-            address += read;
-            size -= read;
         }
     }
 
diff --git a/src/debug/createdump/dumpwriter.h b/src/debug/createdump/dumpwriter.h
index 0b4f88cbd6..7da0d63ccf 100644
--- a/src/debug/createdump/dumpwriter.h
+++ b/src/debug/createdump/dumpwriter.h
@@ -69,9 +69,3 @@ private:
         );
     }
 };
-
-static inline int sex()
-{
-  int probe = 1;
-  return !*(char *)&probe;
-}
diff --git a/src/debug/createdump/memoryregion.h b/src/debug/createdump/memoryregion.h
index 1332ab1416..1f6c5f53e6 100644
--- a/src/debug/createdump/memoryregion.h
+++ b/src/debug/createdump/memoryregion.h
@@ -2,20 +2,31 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+enum MEMORY_REGION_FLAGS : uint32_t
+{
+    // PF_X        = 0x01,      // Execute
+    // PF_W        = 0x02,      // Write
+    // PF_R        = 0x04,      // Read
+    MEMORY_REGION_FLAG_PERMISSIONS_MASK = 0x0f,
+    MEMORY_REGION_FLAG_SHARED = 0x10,
+    MEMORY_REGION_FLAG_PRIVATE = 0x20,
+    MEMORY_REGION_FLAG_MEMORY_BACKED = 0x40
+};
+
 struct MemoryRegion 
 {
 private:
-    uint32_t m_permissions;
+    uint32_t m_flags;
     uint64_t m_startAddress;
     uint64_t m_endAddress;
     uint64_t m_offset;
 
     // The name used for NT_FILE output
-    char* m_fileName;
+    const char* m_fileName;
 
 public:
-    MemoryRegion(uint64_t start, uint64_t end) : 
-        m_permissions(PF_R | PF_W | PF_X),
+    MemoryRegion(uint32_t flags, uint64_t start, uint64_t end) : 
+        m_flags(flags),
         m_startAddress(start),
         m_endAddress(end),
         m_offset(0),
@@ -25,8 +36,8 @@ public:
         assert((end & ~PAGE_MASK) == 0);
     }
 
-    MemoryRegion(uint32_t permissions, uint64_t start, uint64_t end, uint64_t offset, char* filename) : 
-        m_permissions(permissions),
+    MemoryRegion(uint32_t flags, uint64_t start, uint64_t end, uint64_t offset, const char* filename) : 
+        m_flags(flags),
         m_startAddress(start),
         m_endAddress(end),
         m_offset(offset),
@@ -36,7 +47,39 @@ public:
         assert((end & ~PAGE_MASK) == 0);
     }
 
-    const uint32_t Permissions() const { return m_permissions; }
+    // copy with new file name constructor
+    MemoryRegion(const MemoryRegion& region, const char* fileName) : 
+        m_flags(region.m_flags),
+        m_startAddress(region.m_startAddress),
+        m_endAddress(region.m_endAddress),
+        m_offset(region.m_offset),
+        m_fileName(fileName)
+    {
+    }
+
+    // copy with new flags constructor. The file name is not copied.
+    MemoryRegion(const MemoryRegion& region, uint32_t flags) : 
+        m_flags(flags),
+        m_startAddress(region.m_startAddress),
+        m_endAddress(region.m_endAddress),
+        m_offset(region.m_offset),
+        m_fileName(nullptr)
+    {
+    }
+
+    // copy constructor
+    MemoryRegion(const MemoryRegion& region) : 
+        m_flags(region.m_flags),
+        m_startAddress(region.m_startAddress),
+        m_endAddress(region.m_endAddress),
+        m_offset(region.m_offset),
+        m_fileName(region.m_fileName)
+    {
+    }
+
+    const uint32_t Permissions() const { return m_flags & MEMORY_REGION_FLAG_PERMISSIONS_MASK; }
+    const uint32_t Flags() const { return m_flags; }
+    const bool IsBackedByMemory() const { return (m_flags & MEMORY_REGION_FLAG_MEMORY_BACKED) != 0; }
     const uint64_t StartAddress() const { return m_startAddress; }
     const uint64_t EndAddress() const { return m_endAddress; }
     const uint64_t Size() const { return m_endAddress - m_startAddress; }
@@ -48,27 +91,25 @@ public:
         return (m_startAddress < rhs.m_startAddress) && (m_endAddress <= rhs.m_startAddress);
     }
 
+    // Returns true if "rhs" is wholly contained in this one
     bool Contains(const MemoryRegion& rhs) const
     {
         return (m_startAddress <= rhs.m_startAddress) && (m_endAddress >= rhs.m_endAddress);
     }
 
+    // Free the file name memory
     void Cleanup()
     {
         if (m_fileName != nullptr)
         {
-            free(m_fileName);
+            free((void*)m_fileName);
             m_fileName = nullptr;
         }
     }
 
-    void Print() const
+    void Trace() const
     {
-        if (m_fileName != nullptr) {
-            TRACE("%016lx - %016lx (%06ld) %016lx %x %s\n", m_startAddress, m_endAddress, (Size() >> PAGE_SHIFT), m_offset, m_permissions, m_fileName);
-        }
-        else {
-            TRACE("%016lx - %016lx (%06ld) %x\n", m_startAddress, m_endAddress, (Size() >> PAGE_SHIFT), m_permissions);
-        }
+        TRACE("%s%016lx - %016lx (%06ld) %016lx %02x %s\n", IsBackedByMemory() ? "*" : " ", m_startAddress, m_endAddress, 
+            (Size() >> PAGE_SHIFT), m_offset, m_flags, m_fileName != nullptr ? m_fileName : "");
     }
 };
diff --git a/src/debug/createdump/threadinfo.cpp b/src/debug/createdump/threadinfo.cpp
index e2c10fc4b7..35a4f0d4cd 100644
--- a/src/debug/createdump/threadinfo.cpp
+++ b/src/debug/createdump/threadinfo.cpp
@@ -145,21 +145,19 @@ ThreadInfo::GetThreadStack(const CrashInfo& crashInfo, uint64_t* startAddress, s
     *startAddress = m_gpRegisters.rsp & PAGE_MASK;
     *size = 4 * PAGE_SIZE;
 
-    for (const MemoryRegion& mapping : crashInfo.OtherMappings())
-    {
-        if (*startAddress >= mapping.StartAddress() && *startAddress < mapping.EndAddress())
+    const MemoryRegion* region = CrashInfo::SearchMemoryRegions(crashInfo.OtherMappings(), *startAddress);
+    if (region != nullptr) {
+
+        // Use the mapping found for the size of the thread's stack
+        *size = region->EndAddress() - *startAddress;
+
+        if (g_diagnostics)
         {
-            // Use the mapping found for the size of the thread's stack
-            *size = mapping.EndAddress() - *startAddress;
-
-            if (g_diagnostics)
-            {
-                TRACE("Thread %04x stack found in other mapping (size %08lx): ", m_tid, *size);
-                mapping.Print();
-            }
-            break;
+            TRACE("Thread %04x stack found in other mapping (size %08lx): ", m_tid, *size);
+            region->Trace();
         }
     }
+    
 }
 
 void