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10.0.0_r6
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art
imgdiag
imgdiag.cc
/* * Copyright (C) 2014 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include "android-base/stringprintf.h" #include "art_field-inl.h" #include "art_method-inl.h" #include "base/array_ref.h" #include "base/os.h" #include "base/string_view_cpp20.h" #include "base/unix_file/fd_file.h" #include "class_linker.h" #include "gc/heap.h" #include "gc/space/image_space.h" #include "image-inl.h" #include "mirror/class-inl.h" #include "mirror/object-inl.h" #include "oat.h" #include "oat_file.h" #include "oat_file_manager.h" #include "scoped_thread_state_change-inl.h" #include "backtrace/BacktraceMap.h" #include "cmdline.h" #include
#include
#include
namespace art { using android::base::StringPrintf; namespace { constexpr size_t kMaxAddressPrint = 5; enum class ProcessType { kZygote, kRemote }; enum class RemoteProcesses { kImageOnly, kZygoteOnly, kImageAndZygote }; struct MappingData { // The count of pages that are considered dirty by the OS. size_t dirty_pages = 0; // The count of pages that differ by at least one byte. size_t different_pages = 0; // The count of differing bytes. size_t different_bytes = 0; // The count of differing four-byte units. size_t different_int32s = 0; // The count of pages that have mapping count == 1. size_t private_pages = 0; // The count of private pages that are also dirty. size_t private_dirty_pages = 0; // The count of pages that are marked dirty but do not differ. size_t false_dirty_pages = 0; // Set of the local virtual page indices that are dirty. std::set
dirty_page_set; }; static std::string GetClassDescriptor(mirror::Class* klass) REQUIRES_SHARED(Locks::mutator_lock_) { CHECK(klass != nullptr); std::string descriptor; const char* descriptor_str = klass->GetDescriptor(&descriptor /*out*/); return std::string(descriptor_str); } static std::string PrettyFieldValue(ArtField* field, mirror::Object* object) REQUIRES_SHARED(Locks::mutator_lock_) { std::ostringstream oss; switch (field->GetTypeAsPrimitiveType()) { case Primitive::kPrimNot: { oss << object->GetFieldObject
( field->GetOffset()); break; } case Primitive::kPrimBoolean: { oss << static_cast
(object->GetFieldBoolean
(field->GetOffset())); break; } case Primitive::kPrimByte: { oss << static_cast
(object->GetFieldByte
(field->GetOffset())); break; } case Primitive::kPrimChar: { oss << object->GetFieldChar
(field->GetOffset()); break; } case Primitive::kPrimShort: { oss << object->GetFieldShort
(field->GetOffset()); break; } case Primitive::kPrimInt: { oss << object->GetField32
(field->GetOffset()); break; } case Primitive::kPrimLong: { oss << object->GetField64
(field->GetOffset()); break; } case Primitive::kPrimFloat: { oss << object->GetField32
(field->GetOffset()); break; } case Primitive::kPrimDouble: { oss << object->GetField64
(field->GetOffset()); break; } case Primitive::kPrimVoid: { oss << "void"; break; } } return oss.str(); } template
static std::vector
> SortByValueDesc( const std::map
map, std::function
value_mapper = [](const D& d) { return static_cast
(d); }) { // Store value->key so that we can use the default sort from pair which // sorts by value first and then key std::vector
> value_key_vector; for (const auto& kv_pair : map) { value_key_vector.push_back(std::make_pair(value_mapper(kv_pair.second), kv_pair.first)); } // Sort in reverse (descending order) std::sort(value_key_vector.rbegin(), value_key_vector.rend()); return value_key_vector; } // Fixup a remote pointer that we read from a foreign boot.art to point to our own memory. // Returned pointer will point to inside of remote_contents. template
static ObjPtr
FixUpRemotePointer(ObjPtr
remote_ptr, ArrayRef
remote_contents, const backtrace_map_t& boot_map) REQUIRES_SHARED(Locks::mutator_lock_) { if (remote_ptr == nullptr) { return nullptr; } uintptr_t remote = reinterpret_cast
(remote_ptr.Ptr()); // In the case the remote pointer is out of range, it probably belongs to another image. // Just return null for this case. if (remote < boot_map.start || remote >= boot_map.end) { return nullptr; } off_t boot_offset = remote - boot_map.start; return reinterpret_cast
(&remote_contents[boot_offset]); } template
static ObjPtr
RemoteContentsPointerToLocal(ObjPtr
remote_ptr, ArrayRef
remote_contents, const ImageHeader& image_header) REQUIRES_SHARED(Locks::mutator_lock_) { if (remote_ptr == nullptr) { return nullptr; } uint8_t* remote = reinterpret_cast
(remote_ptr.Ptr()); ptrdiff_t boot_offset = remote - &remote_contents[0]; const uint8_t* local_ptr = reinterpret_cast
(&image_header) + boot_offset; return reinterpret_cast
(const_cast
(local_ptr)); } template
size_t EntrySize(T* entry); template<> size_t EntrySize(mirror::Object* object) REQUIRES_SHARED(Locks::mutator_lock_) { return object->SizeOf(); } template<> size_t EntrySize(ArtMethod* art_method) REQUIRES_SHARED(Locks::mutator_lock_) { return sizeof(*art_method); } // entry1 and entry2 might be relocated, this means we must use the runtime image's entry // (image_entry) to avoid crashes. template
static bool EntriesDiffer(T* image_entry, T* entry1, T* entry2) REQUIRES_SHARED(Locks::mutator_lock_) { // Use the image entry since entry1 and entry2 might both be remote and relocated. return memcmp(entry1, entry2, EntrySize(image_entry)) != 0; } template
struct RegionCommon { public: RegionCommon(std::ostream* os, ArrayRef
remote_contents, ArrayRef
zygote_contents, const backtrace_map_t& boot_map, const ImageHeader& image_header) : os_(*os), remote_contents_(remote_contents), zygote_contents_(zygote_contents), boot_map_(boot_map), image_header_(image_header), different_entries_(0), dirty_entry_bytes_(0), false_dirty_entry_bytes_(0) { CHECK(!remote_contents.empty()); } void DumpSamplesAndOffsetCount() { os_ << " sample object addresses: "; for (size_t i = 0; i < dirty_entries_.size() && i < kMaxAddressPrint; ++i) { T* entry = dirty_entries_[i]; os_ << reinterpret_cast
(entry) << ", "; } os_ << "\n"; os_ << " dirty byte +offset:count list = "; std::vector
> field_dirty_count_sorted = SortByValueDesc
(field_dirty_count_); for (const std::pair
& pair : field_dirty_count_sorted) { off_t offset = pair.second; size_t count = pair.first; os_ << "+" << offset << ":" << count << ", "; } os_ << "\n"; } size_t GetDifferentEntryCount() const { return different_entries_; } size_t GetDirtyEntryBytes() const { return dirty_entry_bytes_; } size_t GetFalseDirtyEntryCount() const { return false_dirty_entries_.size(); } size_t GetFalseDirtyEntryBytes() const { return false_dirty_entry_bytes_; } size_t GetZygoteDirtyEntryCount() const { return zygote_dirty_entries_.size(); } protected: bool IsEntryOnDirtyPage(T* entry, const std::set
& dirty_pages) const REQUIRES_SHARED(Locks::mutator_lock_) { size_t size = EntrySize(entry); size_t page_off = 0; size_t current_page_idx; uintptr_t entry_address = reinterpret_cast
(entry); // Iterate every page this entry belongs to do { current_page_idx = entry_address / kPageSize + page_off; if (dirty_pages.find(current_page_idx) != dirty_pages.end()) { // This entry is on a dirty page return true; } page_off++; } while ((current_page_idx * kPageSize) < RoundUp(entry_address + size, kObjectAlignment)); return false; } void AddZygoteDirtyEntry(T* entry) REQUIRES_SHARED(Locks::mutator_lock_) { zygote_dirty_entries_.insert(entry); } void AddImageDirtyEntry(T* entry) REQUIRES_SHARED(Locks::mutator_lock_) { image_dirty_entries_.insert(entry); } void AddFalseDirtyEntry(T* entry) REQUIRES_SHARED(Locks::mutator_lock_) { false_dirty_entries_.push_back(entry); false_dirty_entry_bytes_ += EntrySize(entry); } // The output stream to write to. std::ostream& os_; // The byte contents of the remote (image) process' image. ArrayRef
remote_contents_; // The byte contents of the zygote process' image. ArrayRef
zygote_contents_; const backtrace_map_t& boot_map_; const ImageHeader& image_header_; // Count of entries that are different. size_t different_entries_; // Local entries that are dirty (differ in at least one byte). size_t dirty_entry_bytes_; std::vector
dirty_entries_; // Local entries that are clean, but located on dirty pages. size_t false_dirty_entry_bytes_; std::vector
false_dirty_entries_; // Image dirty entries // If zygote_pid_only_ == true, these are shared dirty entries in the zygote. // If zygote_pid_only_ == false, these are private dirty entries in the application. std::set
image_dirty_entries_; // Zygote dirty entries (probably private dirty). // We only add entries here if they differed in both the image and the zygote, so // they are probably private dirty. std::set
zygote_dirty_entries_; std::map
field_dirty_count_; private: DISALLOW_COPY_AND_ASSIGN(RegionCommon); }; template
class RegionSpecializedBase : public RegionCommon
{ }; // Region analysis for mirror::Objects class ImgObjectVisitor : public ObjectVisitor { public: using ComputeDirtyFunc = std::function
& dirty_pages)>; ImgObjectVisitor(ComputeDirtyFunc dirty_func, const uint8_t* begin_image_ptr, const std::set
& dirty_pages) : dirty_func_(std::move(dirty_func)), begin_image_ptr_(begin_image_ptr), dirty_pages_(dirty_pages) { } ~ImgObjectVisitor() override { } void Visit(mirror::Object* object) override REQUIRES_SHARED(Locks::mutator_lock_) { // Sanity check that we are reading a real mirror::Object CHECK(object->GetClass() != nullptr) << "Image object at address " << object << " has null class"; if (kUseBakerReadBarrier) { object->AssertReadBarrierState(); } dirty_func_(object, begin_image_ptr_, dirty_pages_); } private: const ComputeDirtyFunc dirty_func_; const uint8_t* begin_image_ptr_; const std::set
& dirty_pages_; }; template<> class RegionSpecializedBase
: public RegionCommon
{ public: RegionSpecializedBase(std::ostream* os, ArrayRef
remote_contents, ArrayRef
zygote_contents, const backtrace_map_t& boot_map, const ImageHeader& image_header, bool dump_dirty_objects) : RegionCommon
(os, remote_contents, zygote_contents, boot_map, image_header), os_(*os), dump_dirty_objects_(dump_dirty_objects) { } // Define a common public type name for use by RegionData. using VisitorClass = ImgObjectVisitor; void VisitEntries(VisitorClass* visitor, uint8_t* base, PointerSize pointer_size) REQUIRES_SHARED(Locks::mutator_lock_) { RegionCommon
::image_header_.VisitObjects(visitor, base, pointer_size); } void VisitEntry(mirror::Object* entry) REQUIRES_SHARED(Locks::mutator_lock_) { // Unconditionally store the class descriptor in case we need it later mirror::Class* klass = entry->GetClass(); class_data_[klass].descriptor = GetClassDescriptor(klass); } void AddCleanEntry(mirror::Object* entry) REQUIRES_SHARED(Locks::mutator_lock_) { class_data_[entry->GetClass()].AddCleanObject(); } void AddFalseDirtyEntry(mirror::Object* entry) REQUIRES_SHARED(Locks::mutator_lock_) { RegionCommon
::AddFalseDirtyEntry(entry); class_data_[entry->GetClass()].AddFalseDirtyObject(entry); } void AddDirtyEntry(mirror::Object* entry, mirror::Object* entry_remote) REQUIRES_SHARED(Locks::mutator_lock_) { size_t entry_size = EntrySize(entry); ++different_entries_; dirty_entry_bytes_ += entry_size; // Log dirty count and objects for class objects only. mirror::Class* klass = entry->GetClass(); if (klass->IsClassClass()) { // Increment counts for the fields that are dirty const uint8_t* current = reinterpret_cast
(entry); const uint8_t* current_remote = reinterpret_cast
(entry_remote); for (size_t i = 0; i < entry_size; ++i) { if (current[i] != current_remote[i]) { field_dirty_count_[i]++; } } dirty_entries_.push_back(entry); } class_data_[klass].AddDirtyObject(entry, entry_remote); } void DiffEntryContents(mirror::Object* entry, uint8_t* remote_bytes, const uint8_t* base_ptr, bool log_dirty_objects) REQUIRES_SHARED(Locks::mutator_lock_) { const char* tabs = " "; // Attempt to find fields for all dirty bytes. mirror::Class* klass = entry->GetClass(); if (entry->IsClass()) { os_ << tabs << "Class " << mirror::Class::PrettyClass(entry->AsClass()) << " " << entry << "\n"; } else { os_ << tabs << "Instance of " << mirror::Class::PrettyClass(klass) << " " << entry << "\n"; } std::unordered_set
dirty_instance_fields; std::unordered_set
dirty_static_fields; // Examine the bytes comprising the Object, computing which fields are dirty // and recording them for later display. If the Object is an array object, // compute the dirty entries. mirror::Object* remote_entry = reinterpret_cast
(remote_bytes); for (size_t i = 0, count = entry->SizeOf(); i < count; ++i) { if (base_ptr[i] != remote_bytes[i]) { ArtField* field = ArtField::FindInstanceFieldWithOffset*exact*/false>(klass, i); if (field != nullptr) { dirty_instance_fields.insert(field); } else if (entry->IsClass()) { field = ArtField::FindStaticFieldWithOffset*exact*/false>(entry->AsClass(), i); if (field != nullptr) { dirty_static_fields.insert(field); } } if (field == nullptr) { if (klass->IsArrayClass()) { ObjPtr
component_type = klass->GetComponentType(); Primitive::Type primitive_type = component_type->GetPrimitiveType(); size_t component_size = Primitive::ComponentSize(primitive_type); size_t data_offset = mirror::Array::DataOffset(component_size).Uint32Value(); DCHECK_ALIGNED_PARAM(data_offset, component_size); if (i >= data_offset) { os_ << tabs << "Dirty array element " << (i - data_offset) / component_size << "\n"; // Skip the remaining bytes of this element to prevent spam. DCHECK(IsPowerOfTwo(component_size)); i |= component_size - 1; continue; } } os_ << tabs << "No field for byte offset " << i << "\n"; } } } // Dump different fields. if (!dirty_instance_fields.empty()) { os_ << tabs << "Dirty instance fields " << dirty_instance_fields.size() << "\n"; for (ArtField* field : dirty_instance_fields) { os_ << tabs << ArtField::PrettyField(field) << " original=" << PrettyFieldValue(field, entry) << " remote=" << PrettyFieldValue(field, remote_entry) << "\n"; } } if (!dirty_static_fields.empty()) { if (dump_dirty_objects_ && log_dirty_objects) { dirty_objects_.insert(entry); } os_ << tabs << "Dirty static fields " << dirty_static_fields.size() << "\n"; for (ArtField* field : dirty_static_fields) { os_ << tabs << ArtField::PrettyField(field) << " original=" << PrettyFieldValue(field, entry) << " remote=" << PrettyFieldValue(field, remote_entry) << "\n"; } } os_ << "\n"; } void DumpDirtyObjects() REQUIRES_SHARED(Locks::mutator_lock_) { for (mirror::Object* obj : dirty_objects_) { if (obj->IsClass()) { os_ << "Private dirty object: " << obj->AsClass()->PrettyDescriptor() << "\n"; } } } void DumpDirtyEntries() REQUIRES_SHARED(Locks::mutator_lock_) { // vector of pairs (size_t count, Class*) auto dirty_object_class_values = SortByValueDesc
( class_data_, [](const ClassData& d) { return d.dirty_object_count; }); os_ << "\n" << " Dirty object count by class:\n"; for (const auto& vk_pair : dirty_object_class_values) { size_t dirty_object_count = vk_pair.first; mirror::Class* klass = vk_pair.second; ClassData& class_data = class_data_[klass]; size_t object_sizes = class_data.dirty_object_size_in_bytes; float avg_dirty_bytes_per_class = class_data.dirty_object_byte_count * 1.0f / object_sizes; float avg_object_size = object_sizes * 1.0f / dirty_object_count; const std::string& descriptor = class_data.descriptor; os_ << " " << mirror::Class::PrettyClass(klass) << " (" << "objects: " << dirty_object_count << ", " << "avg dirty bytes: " << avg_dirty_bytes_per_class << ", " << "avg object size: " << avg_object_size << ", " << "class descriptor: '" << descriptor << "'" << ")\n"; if (strcmp(descriptor.c_str(), "Ljava/lang/Class;") == 0) { DumpSamplesAndOffsetCount(); os_ << " field contents:\n"; for (mirror::Object* object : class_data.dirty_objects) { // remote class object ObjPtr
remote_klass = ObjPtr
::DownCast
(object); // local class object ObjPtr
local_klass = RemoteContentsPointerToLocal(remote_klass, RegionCommon
::remote_contents_, RegionCommon
::image_header_); os_ << " " << reinterpret_cast
(object) << " "; os_ << " class_status (remote): " << remote_klass->GetStatus() << ", "; os_ << " class_status (local): " << local_klass->GetStatus(); os_ << "\n"; } } } } void DumpFalseDirtyEntries() REQUIRES_SHARED(Locks::mutator_lock_) { // vector of pairs (size_t count, Class*) auto false_dirty_object_class_values = SortByValueDesc
( class_data_, [](const ClassData& d) { return d.false_dirty_object_count; }); os_ << "\n" << " False-dirty object count by class:\n"; for (const auto& vk_pair : false_dirty_object_class_values) { size_t object_count = vk_pair.first; mirror::Class* klass = vk_pair.second; ClassData& class_data = class_data_[klass]; size_t object_sizes = class_data.false_dirty_byte_count; float avg_object_size = object_sizes * 1.0f / object_count; const std::string& descriptor = class_data.descriptor; os_ << " " << mirror::Class::PrettyClass(klass) << " (" << "objects: " << object_count << ", " << "avg object size: " << avg_object_size << ", " << "total bytes: " << object_sizes << ", " << "class descriptor: '" << descriptor << "'" << ")\n"; } } void DumpCleanEntries() REQUIRES_SHARED(Locks::mutator_lock_) { // vector of pairs (size_t count, Class*) auto clean_object_class_values = SortByValueDesc
( class_data_, [](const ClassData& d) { return d.clean_object_count; }); os_ << "\n" << " Clean object count by class:\n"; for (const auto& vk_pair : clean_object_class_values) { os_ << " " << mirror::Class::PrettyClass(vk_pair.second) << " (" << vk_pair.first << ")\n"; } } private: // Aggregate and detail class data from an image diff. struct ClassData { size_t dirty_object_count = 0; // Track only the byte-per-byte dirtiness (in bytes) size_t dirty_object_byte_count = 0; // Track the object-by-object dirtiness (in bytes) size_t dirty_object_size_in_bytes = 0; size_t clean_object_count = 0; std::string descriptor; size_t false_dirty_byte_count = 0; size_t false_dirty_object_count = 0; std::vector
false_dirty_objects; // Remote pointers to dirty objects std::vector
dirty_objects; void AddCleanObject() REQUIRES_SHARED(Locks::mutator_lock_) { ++clean_object_count; } void AddDirtyObject(mirror::Object* object, mirror::Object* object_remote) REQUIRES_SHARED(Locks::mutator_lock_) { ++dirty_object_count; dirty_object_byte_count += CountDirtyBytes(object, object_remote); dirty_object_size_in_bytes += EntrySize(object); dirty_objects.push_back(object_remote); } void AddFalseDirtyObject(mirror::Object* object) REQUIRES_SHARED(Locks::mutator_lock_) { ++false_dirty_object_count; false_dirty_objects.push_back(object); false_dirty_byte_count += EntrySize(object); } private: // Go byte-by-byte and figure out what exactly got dirtied static size_t CountDirtyBytes(mirror::Object* object1, mirror::Object* object2) REQUIRES_SHARED(Locks::mutator_lock_) { const uint8_t* cur1 = reinterpret_cast
(object1); const uint8_t* cur2 = reinterpret_cast
(object2); size_t dirty_bytes = 0; size_t object_size = EntrySize(object1); for (size_t i = 0; i < object_size; ++i) { if (cur1[i] != cur2[i]) { dirty_bytes++; } } return dirty_bytes; } }; std::ostream& os_; bool dump_dirty_objects_; std::unordered_set
dirty_objects_; std::map
class_data_; DISALLOW_COPY_AND_ASSIGN(RegionSpecializedBase); }; // Region analysis for ArtMethods. class ImgArtMethodVisitor { public: using ComputeDirtyFunc = std::function
&)>; ImgArtMethodVisitor(ComputeDirtyFunc dirty_func, const uint8_t* begin_image_ptr, const std::set
& dirty_pages) : dirty_func_(std::move(dirty_func)), begin_image_ptr_(begin_image_ptr), dirty_pages_(dirty_pages) { } void operator()(ArtMethod& method) const { dirty_func_(&method, begin_image_ptr_, dirty_pages_); } private: const ComputeDirtyFunc dirty_func_; const uint8_t* begin_image_ptr_; const std::set
& dirty_pages_; }; // Struct and functor for computing offsets of members of ArtMethods. // template
struct MemberInfo { template
void operator() (const ArtMethod* method, const T* member_address, const std::string& name) { // Check that member_address is a pointer inside *method. DCHECK(reinterpret_cast
(method) <= reinterpret_cast
(member_address)); DCHECK(reinterpret_cast
(member_address) + sizeof(T) <= reinterpret_cast
(method) + sizeof(ArtMethod)); size_t offset = reinterpret_cast
(member_address) - reinterpret_cast
(method); offset_to_name_size_.insert({offset, NameAndSize(sizeof(T), name)}); } struct NameAndSize { size_t size_; std::string name_; NameAndSize(size_t size, const std::string& name) : size_(size), name_(name) { } NameAndSize() : size_(0), name_("INVALID") { } }; std::map
offset_to_name_size_; }; template<> class RegionSpecializedBase
: public RegionCommon
{ public: RegionSpecializedBase(std::ostream* os, ArrayRef
remote_contents, ArrayRef
zygote_contents, const backtrace_map_t& boot_map, const ImageHeader& image_header, bool dump_dirty_objects ATTRIBUTE_UNUSED) : RegionCommon
(os, remote_contents, zygote_contents, boot_map, image_header), os_(*os) { // Prepare the table for offset to member lookups. ArtMethod* art_method = reinterpret_cast
(&remote_contents[0]); art_method->VisitMembers(member_info_); // Prepare the table for address to symbolic entry point names. BuildEntryPointNames(); class_linker_ = Runtime::Current()->GetClassLinker(); } // Define a common public type name for use by RegionData. using VisitorClass = ImgArtMethodVisitor; void VisitEntries(VisitorClass* visitor, uint8_t* base, PointerSize pointer_size) REQUIRES_SHARED(Locks::mutator_lock_) { RegionCommon
::image_header_.VisitPackedArtMethods(*visitor, base, pointer_size); } void VisitEntry(ArtMethod* method ATTRIBUTE_UNUSED) REQUIRES_SHARED(Locks::mutator_lock_) { } void AddCleanEntry(ArtMethod* method ATTRIBUTE_UNUSED) { } void AddFalseDirtyEntry(ArtMethod* method) REQUIRES_SHARED(Locks::mutator_lock_) { RegionCommon
::AddFalseDirtyEntry(method); } void AddDirtyEntry(ArtMethod* method, ArtMethod* method_remote) REQUIRES_SHARED(Locks::mutator_lock_) { size_t entry_size = EntrySize(method); ++different_entries_; dirty_entry_bytes_ += entry_size; // Increment counts for the fields that are dirty const uint8_t* current = reinterpret_cast
(method); const uint8_t* current_remote = reinterpret_cast
(method_remote); // ArtMethods always log their dirty count and entries. for (size_t i = 0; i < entry_size; ++i) { if (current[i] != current_remote[i]) { field_dirty_count_[i]++; } } dirty_entries_.push_back(method); } void DiffEntryContents(ArtMethod* method, uint8_t* remote_bytes, const uint8_t* base_ptr, bool log_dirty_objects ATTRIBUTE_UNUSED) REQUIRES_SHARED(Locks::mutator_lock_) { const char* tabs = " "; os_ << tabs << "ArtMethod " << ArtMethod::PrettyMethod(method) << "\n"; std::unordered_set
dirty_members; // Examine the members comprising the ArtMethod, computing which members are dirty. for (const std::pair
& p : member_info_.offset_to_name_size_) { const size_t offset = p.first; if (memcmp(base_ptr + offset, remote_bytes + offset, p.second.size_) != 0) { dirty_members.insert(p.first); } } // Dump different fields. if (!dirty_members.empty()) { os_ << tabs << "Dirty members " << dirty_members.size() << "\n"; for (size_t offset : dirty_members) { const MemberInfo::NameAndSize& member_info = member_info_.offset_to_name_size_[offset]; os_ << tabs << member_info.name_ << " original=" << StringFromBytes(base_ptr + offset, member_info.size_) << " remote=" << StringFromBytes(remote_bytes + offset, member_info.size_) << "\n"; } } os_ << "\n"; } void DumpDirtyObjects() REQUIRES_SHARED(Locks::mutator_lock_) { } void DumpDirtyEntries() REQUIRES_SHARED(Locks::mutator_lock_) { DumpSamplesAndOffsetCount(); os_ << " offset to field map:\n"; for (const std::pair
& p : member_info_.offset_to_name_size_) { const size_t offset = p.first; const size_t size = p.second.size_; os_ << StringPrintf(" %zu-%zu: ", offset, offset + size - 1) << p.second.name_ << std::endl; } os_ << " field contents:\n"; for (ArtMethod* method : dirty_entries_) { // remote method auto art_method = reinterpret_cast
(method); // remote class ObjPtr
remote_declaring_class = FixUpRemotePointer(art_method->GetDeclaringClass(), RegionCommon
::remote_contents_, RegionCommon
::boot_map_); // local class ObjPtr
declaring_class = RemoteContentsPointerToLocal(remote_declaring_class, RegionCommon
::remote_contents_, RegionCommon
::image_header_); DumpOneArtMethod(art_method, declaring_class, remote_declaring_class); } } void DumpFalseDirtyEntries() REQUIRES_SHARED(Locks::mutator_lock_) { os_ << "\n" << " False-dirty ArtMethods\n"; os_ << " field contents:\n"; for (ArtMethod* method : false_dirty_entries_) { // local class ObjPtr
declaring_class = method->GetDeclaringClass(); DumpOneArtMethod(method, declaring_class, nullptr); } } void DumpCleanEntries() REQUIRES_SHARED(Locks::mutator_lock_) { } private: std::ostream& os_; MemberInfo member_info_; std::map
entry_point_names_; ClassLinker* class_linker_; // Compute a map of addresses to names in the boot OAT file(s). void BuildEntryPointNames() { OatFileManager& oat_file_manager = Runtime::Current()->GetOatFileManager(); std::vector
boot_oat_files = oat_file_manager.GetBootOatFiles(); for (const OatFile* oat_file : boot_oat_files) { const OatHeader& oat_header = oat_file->GetOatHeader(); const void* jdl = oat_header.GetJniDlsymLookup(); if (jdl != nullptr) { entry_point_names_[jdl] = "JniDlsymLookup (from boot oat file)"; } const void* qgjt = oat_header.GetQuickGenericJniTrampoline(); if (qgjt != nullptr) { entry_point_names_[qgjt] = "QuickGenericJniTrampoline (from boot oat file)"; } const void* qrt = oat_header.GetQuickResolutionTrampoline(); if (qrt != nullptr) { entry_point_names_[qrt] = "QuickResolutionTrampoline (from boot oat file)"; } const void* qict = oat_header.GetQuickImtConflictTrampoline(); if (qict != nullptr) { entry_point_names_[qict] = "QuickImtConflictTrampoline (from boot oat file)"; } const void* q2ib = oat_header.GetQuickToInterpreterBridge(); if (q2ib != nullptr) { entry_point_names_[q2ib] = "QuickToInterpreterBridge (from boot oat file)"; } } } std::string StringFromBytes(const uint8_t* bytes, size_t size) { switch (size) { case 1: return StringPrintf("%" PRIx8, *bytes); case 2: return StringPrintf("%" PRIx16, *reinterpret_cast
(bytes)); case 4: case 8: { // Compute an address if the bytes might contain one. uint64_t intval; if (size == 4) { intval = *reinterpret_cast
(bytes); } else { intval = *reinterpret_cast
(bytes); } const void* addr = reinterpret_cast
(intval); // Match the address against those that have Is* methods in the ClassLinker. if (class_linker_->IsQuickToInterpreterBridge(addr)) { return "QuickToInterpreterBridge"; } else if (class_linker_->IsQuickGenericJniStub(addr)) { return "QuickGenericJniStub"; } else if (class_linker_->IsQuickResolutionStub(addr)) { return "QuickResolutionStub"; } else if (class_linker_->IsJniDlsymLookupStub(addr)) { return "JniDlsymLookupStub"; } // Match the address against those that we saved from the boot OAT files. if (entry_point_names_.find(addr) != entry_point_names_.end()) { return entry_point_names_[addr]; } return StringPrintf("%" PRIx64, intval); } default: LOG(WARNING) << "Don't know how to convert " << size << " bytes to integer"; return "
"; } } void DumpOneArtMethod(ArtMethod* art_method, ObjPtr
declaring_class, ObjPtr
remote_declaring_class) REQUIRES_SHARED(Locks::mutator_lock_) { PointerSize pointer_size = InstructionSetPointerSize(Runtime::Current()->GetInstructionSet()); os_ << " " << reinterpret_cast
(art_method) << " "; os_ << " entryPointFromJni: " << reinterpret_cast
(art_method->GetDataPtrSize(pointer_size)) << ", "; os_ << " entryPointFromQuickCompiledCode: " << reinterpret_cast
( art_method->GetEntryPointFromQuickCompiledCodePtrSize(pointer_size)) << ", "; os_ << " isNative? " << (art_method->IsNative() ? "yes" : "no") << ", "; // Null for runtime metionds. if (declaring_class != nullptr) { os_ << " class_status (local): " << declaring_class->GetStatus(); } if (remote_declaring_class != nullptr) { os_ << ", class_status (remote): " << remote_declaring_class->GetStatus(); } os_ << "\n"; } DISALLOW_COPY_AND_ASSIGN(RegionSpecializedBase); }; template
class RegionData : public RegionSpecializedBase
{ public: RegionData(std::ostream* os, ArrayRef
remote_contents, ArrayRef
zygote_contents, const backtrace_map_t& boot_map, const ImageHeader& image_header, bool dump_dirty_objects) : RegionSpecializedBase
(os, remote_contents, zygote_contents, boot_map, image_header, dump_dirty_objects), os_(*os) { CHECK(!remote_contents.empty()); } // Walk over the type T entries in theregion between begin_image_ptr and end_image_ptr, // collecting and reporting data regarding dirty, difference, etc. void ProcessRegion(const MappingData& mapping_data, RemoteProcesses remotes, const uint8_t* begin_image_ptr) REQUIRES_SHARED(Locks::mutator_lock_) { typename RegionSpecializedBase
::VisitorClass visitor( [this](T* entry, const uint8_t* begin_image_ptr, const std::set
& dirty_page_set) REQUIRES_SHARED(Locks::mutator_lock_) { this->ComputeEntryDirty(entry, begin_image_ptr, dirty_page_set); }, begin_image_ptr, mapping_data.dirty_page_set); PointerSize pointer_size = InstructionSetPointerSize(Runtime::Current()->GetInstructionSet()); RegionSpecializedBase
::VisitEntries(&visitor, const_cast
(begin_image_ptr), pointer_size); // Looking at only dirty pages, figure out how many of those bytes belong to dirty entries. // TODO: fix this now that there are multiple regions in a mapping. float true_dirtied_percent = RegionCommon
::GetDirtyEntryBytes() * 1.0f / (mapping_data.dirty_pages * kPageSize); // Entry specific statistics. os_ << RegionCommon
::GetDifferentEntryCount() << " different entries, \n " << RegionCommon
::GetDirtyEntryBytes() << " different entry [bytes], \n " << RegionCommon
::GetFalseDirtyEntryCount() << " false dirty entries,\n " << RegionCommon
::GetFalseDirtyEntryBytes() << " false dirty entry [bytes], \n " << true_dirtied_percent << " different entries-vs-total in a dirty page;\n " << "\n"; const uint8_t* base_ptr = begin_image_ptr; switch (remotes) { case RemoteProcesses::kZygoteOnly: os_ << " Zygote shared dirty entries: "; break; case RemoteProcesses::kImageAndZygote: os_ << " Application dirty entries (private dirty): "; // If we are dumping private dirty, diff against the zygote map to make it clearer what // fields caused the page to be private dirty. base_ptr = RegionCommon
::zygote_contents_.data(); break; case RemoteProcesses::kImageOnly: os_ << " Application dirty entries (unknown whether private or shared dirty): "; break; } DiffDirtyEntries(ProcessType::kRemote, begin_image_ptr, RegionCommon
::remote_contents_, base_ptr, /*log_dirty_objects=*/true); // Print shared dirty after since it's less important. if (RegionCommon
::GetZygoteDirtyEntryCount() != 0) { // We only reach this point if both pids were specified. Furthermore, // entries are only displayed here if they differed in both the image // and the zygote, so they are probably private dirty. CHECK(remotes == RemoteProcesses::kImageAndZygote); os_ << "\n" << " Zygote dirty entries (probably shared dirty): "; DiffDirtyEntries(ProcessType::kZygote, begin_image_ptr, RegionCommon
::zygote_contents_, begin_image_ptr, /*log_dirty_objects=*/false); } RegionSpecializedBase
::DumpDirtyObjects(); RegionSpecializedBase
::DumpDirtyEntries(); RegionSpecializedBase
::DumpFalseDirtyEntries(); RegionSpecializedBase
::DumpCleanEntries(); } private: std::ostream& os_; void DiffDirtyEntries(ProcessType process_type, const uint8_t* begin_image_ptr, ArrayRef
contents, const uint8_t* base_ptr, bool log_dirty_objects) REQUIRES_SHARED(Locks::mutator_lock_) { os_ << RegionCommon
::dirty_entries_.size() << "\n"; const std::set
& entries = (process_type == ProcessType::kZygote) ? RegionCommon
::zygote_dirty_entries_: RegionCommon
::image_dirty_entries_; for (T* entry : entries) { uint8_t* entry_bytes = reinterpret_cast
(entry); ptrdiff_t offset = entry_bytes - begin_image_ptr; uint8_t* remote_bytes = &contents[offset]; RegionSpecializedBase
::DiffEntryContents(entry, remote_bytes, &base_ptr[offset], log_dirty_objects); } } void ComputeEntryDirty(T* entry, const uint8_t* begin_image_ptr, const std::set
& dirty_pages) REQUIRES_SHARED(Locks::mutator_lock_) { // Set up pointers in the remote and the zygote for comparison. uint8_t* current = reinterpret_cast
(entry); ptrdiff_t offset = current - begin_image_ptr; T* entry_remote = reinterpret_cast
(const_cast
(&RegionCommon
::remote_contents_[offset])); const bool have_zygote = !RegionCommon
::zygote_contents_.empty(); const uint8_t* current_zygote = have_zygote ? &RegionCommon
::zygote_contents_[offset] : nullptr; T* entry_zygote = reinterpret_cast
(const_cast
(current_zygote)); // Visit and classify entries at the current location. RegionSpecializedBase
::VisitEntry(entry); // Test private dirty first. bool is_dirty = false; if (have_zygote) { bool private_dirty = EntriesDiffer(entry, entry_zygote, entry_remote); if (private_dirty) { // Private dirty, app vs zygote. is_dirty = true; RegionCommon
::AddImageDirtyEntry(entry); } if (EntriesDiffer(entry, entry_zygote, entry)) { // Shared dirty, zygote vs image. is_dirty = true; RegionCommon
::AddZygoteDirtyEntry(entry); } } else if (EntriesDiffer(entry, entry_remote, entry)) { // Shared or private dirty, app vs image. is_dirty = true; RegionCommon
::AddImageDirtyEntry(entry); } if (is_dirty) { // TODO: Add support dirty entries in zygote and image. RegionSpecializedBase
::AddDirtyEntry(entry, entry_remote); } else { RegionSpecializedBase
::AddCleanEntry(entry); if (RegionCommon
::IsEntryOnDirtyPage(entry, dirty_pages)) { // This entry was either never mutated or got mutated back to the same value. // TODO: Do I want to distinguish a "different" vs a "dirty" page here? RegionSpecializedBase
::AddFalseDirtyEntry(entry); } } } DISALLOW_COPY_AND_ASSIGN(RegionData); }; } // namespace class ImgDiagDumper { public: explicit ImgDiagDumper(std::ostream* os, pid_t image_diff_pid, pid_t zygote_diff_pid, bool dump_dirty_objects) : os_(os), image_diff_pid_(image_diff_pid), zygote_diff_pid_(zygote_diff_pid), dump_dirty_objects_(dump_dirty_objects), zygote_pid_only_(false) {} bool Init() { std::ostream& os = *os_; if (image_diff_pid_ < 0 && zygote_diff_pid_ < 0) { os << "Either --image-diff-pid or --zygote-diff-pid (or both) must be specified.\n"; return false; } // To avoid the combinations of command-line argument use cases: // If the user invoked with only --zygote-diff-pid, shuffle that to // image_diff_pid_, invalidate zygote_diff_pid_, and remember that // image_diff_pid_ is now special. if (image_diff_pid_ < 0) { image_diff_pid_ = zygote_diff_pid_; zygote_diff_pid_ = -1; zygote_pid_only_ = true; } { struct stat sts; std::string proc_pid_str = StringPrintf("/proc/%ld", static_cast
(image_diff_pid_)); // NOLINT [runtime/int] if (stat(proc_pid_str.c_str(), &sts) == -1) { os << "Process does not exist"; return false; } } auto open_proc_maps = [&os](pid_t pid, /*out*/ std::unique_ptr
* proc_maps) { // Open /proc/
/maps to view memory maps. proc_maps->reset(BacktraceMap::Create(pid)); if (*proc_maps == nullptr) { os << "Could not read backtrace maps for " << pid; return false; } return true; }; auto open_file = [&os] (const char* file_name, /*out*/ std::unique_ptr
* file) { file->reset(OS::OpenFileForReading(file_name)); if (*file == nullptr) { os << "Failed to open " << file_name << " for reading"; return false; } return true; }; auto open_mem_file = [&open_file](pid_t pid, /*out*/ std::unique_ptr
* mem_file) { // Open /proc/
/mem and for reading remote contents. std::string mem_file_name = StringPrintf("/proc/%ld/mem", static_cast
(pid)); // NOLINT [runtime/int] return open_file(mem_file_name.c_str(), mem_file); }; auto open_pagemap_file = [&open_file](pid_t pid, /*out*/ std::unique_ptr
* pagemap_file) { // Open /proc/
/pagemap. std::string pagemap_file_name = StringPrintf( "/proc/%ld/pagemap", static_cast
(pid)); // NOLINT [runtime/int] return open_file(pagemap_file_name.c_str(), pagemap_file); }; // Open files for inspecting image memory. std::unique_ptr
image_proc_maps; std::unique_ptr
image_mem_file; std::unique_ptr
image_pagemap_file; if (!open_proc_maps(image_diff_pid_, &image_proc_maps) || !open_mem_file(image_diff_pid_, &image_mem_file) || !open_pagemap_file(image_diff_pid_, &image_pagemap_file)) { return false; } // If zygote_diff_pid_ != -1, open files for inspecting zygote memory. std::unique_ptr
zygote_proc_maps; std::unique_ptr
zygote_mem_file; std::unique_ptr
zygote_pagemap_file; if (zygote_diff_pid_ != -1) { if (!open_proc_maps(zygote_diff_pid_, &zygote_proc_maps) || !open_mem_file(zygote_diff_pid_, &zygote_mem_file) || !open_pagemap_file(zygote_diff_pid_, &zygote_pagemap_file)) { return false; } } std::unique_ptr
clean_pagemap_file; std::unique_ptr
kpageflags_file; std::unique_ptr
kpagecount_file; if (!open_file("/proc/self/pagemap", &clean_pagemap_file) || !open_file("/proc/kpageflags", &kpageflags_file) || !open_file("/proc/kpagecount", &kpagecount_file)) { return false; } // Note: the boot image is not really clean but close enough. // For now, log pages found to be dirty. // TODO: Rewrite imgdiag to load boot image without creating a runtime. // FIXME: The following does not reliably detect dirty pages. Runtime* runtime = Runtime::Current(); CHECK(!runtime->ShouldRelocate()); size_t total_dirty_pages = 0u; for (gc::space::ImageSpace* space : runtime->GetHeap()->GetBootImageSpaces()) { const ImageHeader& image_header = space->GetImageHeader(); const uint8_t* image_begin = image_header.GetImageBegin(); const uint8_t* image_end = AlignUp(image_begin + image_header.GetImageSize(), kPageSize); size_t virtual_page_idx_begin = reinterpret_cast
(image_begin) / kPageSize; size_t virtual_page_idx_end = reinterpret_cast
(image_end) / kPageSize; size_t num_virtual_pages = virtual_page_idx_end - virtual_page_idx_begin; std::string error_msg; std::vector
page_frame_numbers(num_virtual_pages); if (!GetPageFrameNumbers(clean_pagemap_file.get(), virtual_page_idx_begin, ArrayRef
(page_frame_numbers), &error_msg)) { os << "Failed to get page frame numbers for image space " << space->GetImageLocation() << ", error: " << error_msg; return false; } std::vector
page_flags(num_virtual_pages); if (!GetPageFlagsOrCounts(kpageflags_file.get(), ArrayRef
(page_frame_numbers), ArrayRef
(page_flags), &error_msg)) { os << "Failed to get page flags for image space " << space->GetImageLocation() << ", error: " << error_msg; return false; } size_t num_dirty_pages = 0u; std::optional
first_dirty_page; for (size_t i = 0u, size = page_flags.size(); i != size; ++i) { if (UNLIKELY((page_flags[i] & kPageFlagsDirtyMask) != 0u)) { ++num_dirty_pages; if (!first_dirty_page.has_value()) { first_dirty_page = i; } } } if (num_dirty_pages != 0u) { DCHECK(first_dirty_page.has_value()); os << "Found " << num_dirty_pages << " dirty pages for " << space->GetImageLocation() << ", first dirty page: " << first_dirty_page.value_or(0u); total_dirty_pages += num_dirty_pages; } } // Commit the mappings and files. image_proc_maps_ = std::move(image_proc_maps); image_mem_file_ = std::move(*image_mem_file); image_pagemap_file_ = std::move(*image_pagemap_file); if (zygote_diff_pid_ != -1) { zygote_proc_maps_ = std::move(zygote_proc_maps); zygote_mem_file_ = std::move(*zygote_mem_file); zygote_pagemap_file_ = std::move(*zygote_pagemap_file); } clean_pagemap_file_ = std::move(*clean_pagemap_file); kpageflags_file_ = std::move(*kpageflags_file); kpagecount_file_ = std::move(*kpagecount_file); return true; } bool Dump(const ImageHeader& image_header, const std::string& image_location) REQUIRES_SHARED(Locks::mutator_lock_) { std::ostream& os = *os_; os << "IMAGE LOCATION: " << image_location << "\n\n"; os << "MAGIC: " << image_header.GetMagic() << "\n\n"; os << "IMAGE BEGIN: " << reinterpret_cast
(image_header.GetImageBegin()) << "\n\n"; PrintPidLine("IMAGE", image_diff_pid_); os << "\n\n"; PrintPidLine("ZYGOTE", zygote_diff_pid_); bool ret = true; if (image_diff_pid_ >= 0 || zygote_diff_pid_ >= 0) { ret = DumpImageDiff(image_header, image_location); os << "\n\n"; } os << std::flush; return ret; } private: bool DumpImageDiff(const ImageHeader& image_header, const std::string& image_location) REQUIRES_SHARED(Locks::mutator_lock_) { return DumpImageDiffMap(image_header, image_location); } bool ComputeDirtyBytes(const ImageHeader& image_header, const uint8_t* image_begin, const backtrace_map_t& boot_map, ArrayRef
remote_contents, MappingData* mapping_data /*out*/) { std::ostream& os = *os_; size_t virtual_page_idx = 0; // Virtual page number (for an absolute memory address) size_t page_idx = 0; // Page index relative to 0 size_t previous_page_idx = 0; // Previous page index relative to 0 // Iterate through one page at a time. Boot map begin/end already implicitly aligned. for (uintptr_t begin = boot_map.start; begin != boot_map.end; begin += kPageSize) { ptrdiff_t offset = begin - boot_map.start; // We treat the image header as part of the memory map for now // If we wanted to change this, we could pass base=start+sizeof(ImageHeader) // But it might still be interesting to see if any of the ImageHeader data mutated const uint8_t* local_ptr = reinterpret_cast
(&image_header) + offset; const uint8_t* remote_ptr = &remote_contents[offset]; if (memcmp(local_ptr, remote_ptr, kPageSize) != 0) { mapping_data->different_pages++; // Count the number of 32-bit integers that are different. for (size_t i = 0; i < kPageSize / sizeof(uint32_t); ++i) { const uint32_t* remote_ptr_int32 = reinterpret_cast
(remote_ptr); const uint32_t* local_ptr_int32 = reinterpret_cast
(local_ptr); if (remote_ptr_int32[i] != local_ptr_int32[i]) { mapping_data->different_int32s++; } } } } std::vector
private_dirty_pages_for_section(ImageHeader::kSectionCount, 0u); // Iterate through one byte at a time. ptrdiff_t page_off_begin = image_header.GetImageBegin() - image_begin; for (uintptr_t begin = boot_map.start; begin != boot_map.end; ++begin) { previous_page_idx = page_idx; ptrdiff_t offset = begin - boot_map.start; // We treat the image header as part of the memory map for now // If we wanted to change this, we could pass base=start+sizeof(ImageHeader) // But it might still be interesting to see if any of the ImageHeader data mutated const uint8_t* local_ptr = reinterpret_cast
(&image_header) + offset; const uint8_t* remote_ptr = &remote_contents[offset]; virtual_page_idx = reinterpret_cast
(local_ptr) / kPageSize; // Calculate the page index, relative to the 0th page where the image begins page_idx = (offset + page_off_begin) / kPageSize; if (*local_ptr != *remote_ptr) { // Track number of bytes that are different mapping_data->different_bytes++; } // Independently count the # of dirty pages on the remote side size_t remote_virtual_page_idx = begin / kPageSize; if (previous_page_idx != page_idx) { uint64_t page_count = 0xC0FFEE; // TODO: virtual_page_idx needs to be from the same process std::string error_msg; int dirtiness = (IsPageDirty(&image_pagemap_file_, // Image-diff-pid procmap &clean_pagemap_file_, // Self procmap &kpageflags_file_, &kpagecount_file_, remote_virtual_page_idx, // potentially "dirty" page virtual_page_idx, // true "clean" page &page_count, &error_msg)); if (dirtiness < 0) { os << error_msg; return false; } else if (dirtiness > 0) { mapping_data->dirty_pages++; mapping_data->dirty_page_set.insert(mapping_data->dirty_page_set.end(), virtual_page_idx); } bool is_dirty = dirtiness > 0; bool is_private = page_count == 1; if (page_count == 1) { mapping_data->private_pages++; } if (is_dirty && is_private) { mapping_data->private_dirty_pages++; for (size_t i = 0; i < ImageHeader::kSectionCount; ++i) { const ImageHeader::ImageSections section = static_cast
(i); if (image_header.GetImageSection(section).Contains(offset)) { ++private_dirty_pages_for_section[i]; } } } } } mapping_data->false_dirty_pages = mapping_data->dirty_pages - mapping_data->different_pages; // Print low-level (bytes, int32s, pages) statistics. os << mapping_data->different_bytes << " differing bytes,\n " << mapping_data->different_int32s << " differing int32s,\n " << mapping_data->different_pages << " differing pages,\n " << mapping_data->dirty_pages << " pages are dirty;\n " << mapping_data->false_dirty_pages << " pages are false dirty;\n " << mapping_data->private_pages << " pages are private;\n " << mapping_data->private_dirty_pages << " pages are Private_Dirty\n " << "\n"; size_t total_private_dirty_pages = std::accumulate(private_dirty_pages_for_section.begin(), private_dirty_pages_for_section.end(), 0u); os << "Image sections (total private dirty pages " << total_private_dirty_pages << ")\n"; for (size_t i = 0; i < ImageHeader::kSectionCount; ++i) { const ImageHeader::ImageSections section = static_cast
(i); os << section << " " << image_header.GetImageSection(section) << " private dirty pages=" << private_dirty_pages_for_section[i] << "\n"; } os << "\n"; return true; } // Look at /proc/$pid/mem and only diff the things from there bool DumpImageDiffMap(const ImageHeader& image_header, const std::string& image_location) REQUIRES_SHARED(Locks::mutator_lock_) { std::ostream& os = *os_; std::string error_msg; std::string image_location_base_name = GetImageLocationBaseName(image_location); // FIXME: BacktraceMap should provide a const_iterator so that we can take `maps` as const&. auto find_boot_map = [&os, &image_location_base_name](BacktraceMap& maps, const char* tag) -> std::optional
{ // Find the memory map for the current boot image component. for (const backtrace_map_t* map : maps) { if (EndsWith(map->name, image_location_base_name)) { if ((map->flags & PROT_WRITE) != 0) { return *map; } // In actuality there's more than 1 map, but the second one is read-only. // The one we care about is the write-able map. // The readonly maps are guaranteed to be identical, so its not interesting to compare // them. } } os << "Could not find map for " << image_location_base_name << " in " << tag; return std::nullopt; }; // Find the current boot image mapping. std::optional
maybe_boot_map = find_boot_map(*image_proc_maps_, "image"); if (maybe_boot_map == std::nullopt) { return false; } backtrace_map_t boot_map = maybe_boot_map.value_or(backtrace_map_t{}); // Sanity check boot_map_. CHECK(boot_map.end >= boot_map.start); // The size of the boot image mapping. size_t boot_map_size = boot_map.end - boot_map.start; // If zygote_diff_pid_ != -1, check that the zygote boot map is the same. if (zygote_diff_pid_ != -1) { std::optional
maybe_zygote_boot_map = find_boot_map(*zygote_proc_maps_, "zygote"); if (maybe_zygote_boot_map == std::nullopt) { return false; } backtrace_map_t zygote_boot_map = maybe_zygote_boot_map.value_or(backtrace_map_t{}); if (zygote_boot_map.start != boot_map.start || zygote_boot_map.end != boot_map.end) { os << "Zygote boot map does not match image boot map: " << "zygote begin " << reinterpret_cast
(zygote_boot_map.start) << ", zygote end " << reinterpret_cast
(zygote_boot_map.end) << ", image begin " << reinterpret_cast
(boot_map.start) << ", image end " << reinterpret_cast
(boot_map.end); return false; } } // Walk the bytes and diff against our boot image os << "\nObserving boot image header at address " << reinterpret_cast
(&image_header) << "\n\n"; const uint8_t* image_begin_unaligned = image_header.GetImageBegin(); const uint8_t* image_end_unaligned = image_begin_unaligned + image_header.GetImageSize(); // Adjust range to nearest page const uint8_t* image_begin = AlignDown(image_begin_unaligned, kPageSize); const uint8_t* image_end = AlignUp(image_end_unaligned, kPageSize); size_t image_size = image_end - image_begin; if (image_size != boot_map_size) { os << "Remote boot map size does not match local boot map size: " << "local size " << image_size << ", remote size " << boot_map_size; return false; } auto read_contents = [&](File* mem_file, /*out*/ MemMap* map, /*out*/ ArrayRef
* contents) { DCHECK_ALIGNED(boot_map.start, kPageSize); DCHECK_ALIGNED(boot_map_size, kPageSize); std::string name = "Contents of " + mem_file->GetPath(); std::string local_error_msg; // We need to use low 4 GiB memory so that we can walk the objects using standard // functions that use ObjPtr<> which is checking that it fits into lower 4 GiB. *map = MemMap::MapAnonymous(name.c_str(), boot_map_size, PROT_READ | PROT_WRITE, /* low_4gb= */ true, &local_error_msg); if (!map->IsValid()) { os << "Failed to allocate anonymous mapping for " << boot_map_size << " bytes.\n"; return false; } if (!mem_file->PreadFully(map->Begin(), boot_map_size, boot_map.start)) { os << "Could not fully read file " << image_mem_file_.GetPath(); return false; } *contents = ArrayRef
(map->Begin(), boot_map_size); return true; }; // The contents of /proc/
/mem. MemMap remote_contents_map; ArrayRef
remote_contents; if (!read_contents(&image_mem_file_, &remote_contents_map, &remote_contents)) { return false; } // The contents of /proc/
/mem. MemMap zygote_contents_map; ArrayRef
zygote_contents; if (zygote_diff_pid_ != -1) { if (!read_contents(&zygote_mem_file_, &zygote_contents_map, &zygote_contents)) { return false; } } // TODO: We need to update the entire diff to work with the ASLR. b/77856493 // Since the images may be relocated, just check the sizes. if (static_cast
(image_end - image_begin) != boot_map.end - boot_map.start) { os << "Remote boot map is a different size than local boot map: " << "local begin " << reinterpret_cast
(image_begin) << ", local end " << reinterpret_cast
(image_end) << ", remote begin " << reinterpret_cast
(boot_map.start) << ", remote end " << reinterpret_cast
(boot_map.end); return false; // For more validation should also check the ImageHeader from the file } MappingData mapping_data; os << "Mapping at [" << reinterpret_cast
(boot_map.start) << ", " << reinterpret_cast
(boot_map.end) << ") had:\n "; if (!ComputeDirtyBytes(image_header, image_begin, boot_map, remote_contents, &mapping_data)) { return false; } RemoteProcesses remotes; if (zygote_pid_only_) { remotes = RemoteProcesses::kZygoteOnly; } else if (zygote_diff_pid_ > 0) { remotes = RemoteProcesses::kImageAndZygote; } else { remotes = RemoteProcesses::kImageOnly; } // Check all the mirror::Object entries in the image. RegionData
object_region_data(os_, remote_contents, zygote_contents, boot_map, image_header, dump_dirty_objects_); object_region_data.ProcessRegion(mapping_data, remotes, image_begin_unaligned); // Check all the ArtMethod entries in the image. RegionData
artmethod_region_data(os_, remote_contents, zygote_contents, boot_map, image_header, dump_dirty_objects_); artmethod_region_data.ProcessRegion(mapping_data, remotes, image_begin_unaligned); return true; } // Note: On failure, `*page_frame_number` shall be clobbered. static bool GetPageFrameNumber(File* page_map_file, size_t virtual_page_index, /*out*/ uint64_t* page_frame_number, /*out*/ std::string* error_msg) { CHECK(page_frame_number != nullptr); return GetPageFrameNumbers(page_map_file, virtual_page_index, ArrayRef
(page_frame_number, 1u), error_msg); } // Note: On failure, `page_frame_numbers[.]` shall be clobbered. static bool GetPageFrameNumbers(File* page_map_file, size_t virtual_page_index, /*out*/ ArrayRef
page_frame_numbers, /*out*/ std::string* error_msg) { CHECK(page_map_file != nullptr); CHECK_NE(page_frame_numbers.size(), 0u); CHECK(page_frame_numbers.data() != nullptr); CHECK(error_msg != nullptr); // Read 64-bit entries from /proc/$pid/pagemap to get the physical page frame numbers. if (!page_map_file->PreadFully(page_frame_numbers.data(), page_frame_numbers.size() * kPageMapEntrySize, virtual_page_index * kPageMapEntrySize)) { *error_msg = StringPrintf("Failed to read the virtual page index entries from %s, error: %s", page_map_file->GetPath().c_str(), strerror(errno)); return false; } // Extract page frame numbers from pagemap entries. for (uint64_t& page_frame_number : page_frame_numbers) { page_frame_number &= kPageFrameNumberMask; } return true; } // Note: On failure, `page_flags_or_counts[.]` shall be clobbered. static bool GetPageFlagsOrCounts(File* kpage_file, ArrayRef
page_frame_numbers, /*out*/ ArrayRef
page_flags_or_counts, /*out*/ std::string* error_msg) { static_assert(kPageFlagsEntrySize == kPageCountEntrySize, "entry size check"); CHECK_NE(page_frame_numbers.size(), 0u); CHECK_EQ(page_flags_or_counts.size(), page_frame_numbers.size()); CHECK(kpage_file != nullptr); CHECK(page_frame_numbers.data() != nullptr); CHECK(page_flags_or_counts.data() != nullptr); CHECK(error_msg != nullptr); size_t size = page_frame_numbers.size(); size_t i = 0; while (i != size) { size_t start = i; ++i; while (i != size && page_frame_numbers[i] - page_frame_numbers[start] == i - start) { ++i; } // Read 64-bit entries from /proc/kpageflags or /proc/kpagecount. if (!kpage_file->PreadFully(page_flags_or_counts.data() + start, (i - start) * kPageMapEntrySize, page_frame_numbers[start] * kPageFlagsEntrySize)) { *error_msg = StringPrintf("Failed to read the page flags or counts from %s, error: %s", kpage_file->GetPath().c_str(), strerror(errno)); return false; } } return true; } static int IsPageDirty(File* page_map_file, File* clean_pagemap_file, File* kpageflags_file, File* kpagecount_file, size_t virtual_page_idx, size_t clean_virtual_page_idx, // Out parameters: uint64_t* page_count, std::string* error_msg) { CHECK(page_map_file != nullptr); CHECK(clean_pagemap_file != nullptr); CHECK_NE(page_map_file, clean_pagemap_file); CHECK(kpageflags_file != nullptr); CHECK(kpagecount_file != nullptr); CHECK(page_count != nullptr); CHECK(error_msg != nullptr); // Constants are from https://www.kernel.org/doc/Documentation/vm/pagemap.txt uint64_t page_frame_number = 0; if (!GetPageFrameNumber(page_map_file, virtual_page_idx, &page_frame_number, error_msg)) { return -1; } uint64_t page_frame_number_clean = 0; if (!GetPageFrameNumber(clean_pagemap_file, clean_virtual_page_idx, &page_frame_number_clean, error_msg)) { return -1; } // Read 64-bit entry from /proc/kpageflags to get the dirty bit for a page uint64_t kpage_flags_entry = 0; if (!kpageflags_file->PreadFully(&kpage_flags_entry, kPageFlagsEntrySize, page_frame_number * kPageFlagsEntrySize)) { *error_msg = StringPrintf("Failed to read the page flags from %s", kpageflags_file->GetPath().c_str()); return -1; } // Read 64-bit entyry from /proc/kpagecount to get mapping counts for a page if (!kpagecount_file->PreadFully(page_count /*out*/, kPageCountEntrySize, page_frame_number * kPageCountEntrySize)) { *error_msg = StringPrintf("Failed to read the page count from %s", kpagecount_file->GetPath().c_str()); return -1; } // There must be a page frame at the requested address. CHECK_EQ(kpage_flags_entry & kPageFlagsNoPageMask, 0u); // The page frame must be memory mapped CHECK_NE(kpage_flags_entry & kPageFlagsMmapMask, 0u); // Page is dirty, i.e. has diverged from file, if the 4th bit is set to 1 bool flags_dirty = (kpage_flags_entry & kPageFlagsDirtyMask) != 0; // page_frame_number_clean must come from the *same* process // but a *different* mmap than page_frame_number if (flags_dirty) { // FIXME: This check sometimes fails and the reason is not understood. b/123852774 if (page_frame_number != page_frame_number_clean) { LOG(ERROR) << "Check failed: page_frame_number != page_frame_number_clean " << "(page_frame_number=" << page_frame_number << ", page_frame_number_clean=" << page_frame_number_clean << ")" << " count: " << *page_count << " flags: 0x" << std::hex << kpage_flags_entry; } } return page_frame_number != page_frame_number_clean; } void PrintPidLine(const std::string& kind, pid_t pid) { if (pid < 0) { *os_ << kind << " DIFF PID: disabled\n\n"; } else { *os_ << kind << " DIFF PID (" << pid << "): "; } } // Return suffix of the file path after the last /. (e.g. /foo/bar -> bar, bar -> bar) static std::string BaseName(const std::string& str) { size_t idx = str.rfind('/'); if (idx == std::string::npos) { return str; } return str.substr(idx + 1); } // Return the image location, stripped of any directories, e.g. "boot.art" or "core.art" static std::string GetImageLocationBaseName(const std::string& image_location) { return BaseName(std::string(image_location)); } static constexpr size_t kPageMapEntrySize = sizeof(uint64_t); // bits 0-54 [in /proc/$pid/pagemap] static constexpr uint64_t kPageFrameNumberMask = (1ULL << 55) - 1; static constexpr size_t kPageFlagsEntrySize = sizeof(uint64_t); static constexpr size_t kPageCountEntrySize = sizeof(uint64_t); static constexpr uint64_t kPageFlagsDirtyMask = (1ULL << 4); // in /proc/kpageflags static constexpr uint64_t kPageFlagsNoPageMask = (1ULL << 20); // in /proc/kpageflags static constexpr uint64_t kPageFlagsMmapMask = (1ULL << 11); // in /proc/kpageflags std::ostream* os_; pid_t image_diff_pid_; // Dump image diff against boot.art if pid is non-negative pid_t zygote_diff_pid_; // Dump image diff against zygote boot.art if pid is non-negative bool dump_dirty_objects_; // Adds dumping of objects that are dirty. bool zygote_pid_only_; // The user only specified a pid for the zygote. // BacktraceMap used for finding the memory mapping of the image file. std::unique_ptr