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[handles] TracedHandles: Rely on AllocateAtLeast()

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Use AllocateAtLeast() to create a TracedNodeBlock. In todays Blink
this increases capacity from 256 to 284, reducing memory and
preserving the fast path longer.

Limit capacity to '1' for ASAN builds to flush out UAFs.

Bug: v8:13372
Change-Id: Iaa0ca940b59ed58015fcb768b851e6054ac7e152
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3999730
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#84131}
This commit is contained in:
Michael Lippautz 2022-11-08 18:32:17 +01:00 committed by V8 LUCI CQ
parent c37c2561e2
commit b5485fd81f
2 changed files with 119 additions and 57 deletions
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2
include/v8-internal.h
View File

@ -581,7 +581,7 @@ class Internals {
static const int kNodeStateMask = 0x3;
static const int kNodeStateIsWeakValue = 2;
static const int kTracedNodeClassIdOffset = kApiSystemPointerSize + 2;
static const int kTracedNodeClassIdOffset = kApiSystemPointerSize;
static const int kFirstNonstringType = 0x80;
static const int kOddballType = 0x83;

172
src/handles/traced-handles.cc
View File

@ -5,10 +5,13 @@
#include "src/handles/traced-handles.h"
#include <iterator>
#include <limits>
#include "include/v8-internal.h"
#include "include/v8-traced-handle.h"
#include "src/base/logging.h"
#include "src/base/platform/memory.h"
#include "src/base/sanitizer/asan.h"
#include "src/common/globals.h"
#include "src/handles/handles.h"
#include "src/heap/heap-write-barrier-inl.h"
@ -22,14 +25,14 @@ namespace {
class TracedNodeBlock;
// TODO(v8:13372): Avoid constant and instead make use of
// `v8::base::AllocateAtLeast()` to maximize utilization of the memory.
constexpr size_t kBlockSize = 256;
constexpr uint16_t kInvalidFreeListNodeIndex = -1;
class TracedNode final {
public:
#ifdef V8_HOST_ARCH_64_BIT
using IndexType = uint16_t;
#else // !V8_HOST_ARCH_64_BIT
using IndexType = uint8_t;
#endif // !V8_HOST_ARCH_64_BIT
static TracedNode* FromLocation(Address* location) {
return reinterpret_cast<TracedNode*>(location);
}
@ -38,10 +41,9 @@ class TracedNode final {
return reinterpret_cast<const TracedNode*>(location);
}
TracedNode() = default;
void Initialize(uint8_t, uint16_t);
TracedNode(IndexType, IndexType);
uint8_t index() const { return index_; }
IndexType index() const { return index_; }
bool is_root() const { return IsRoot::decode(flags_); }
void set_root(bool v) { flags_ = IsRoot::update(flags_, v); }
@ -63,8 +65,8 @@ class TracedNode final {
flags_ = IsInYoungList::update(flags_, v);
}
uint16_t next_free() const { return next_free_index_; }
void set_next_free(uint16_t next_free_index) {
IndexType next_free() const { return next_free_index_; }
void set_next_free(IndexType next_free_index) {
next_free_index_ = next_free_index;
}
void set_class_id(uint16_t class_id) { class_id_ = class_id; }
@ -114,25 +116,26 @@ class TracedNode final {
using Markbit = IsRoot::Next<bool, 1>;
Address object_ = kNullAddress;
uint8_t index_ = 0;
uint8_t flags_ = 0;
union {
// When a node is not in use, this index is used to build the free list.
uint16_t next_free_index_;
// When a node is in use, the user can specify a class id.
uint16_t class_id_;
// When a node is not in use, this index is used to build the free list.
IndexType next_free_index_;
};
IndexType index_;
uint8_t flags_ = 0;
};
void TracedNode::Initialize(uint8_t index, uint16_t next_free_index) {
TracedNode::TracedNode(IndexType index, IndexType next_free_index)
: next_free_index_(next_free_index), index_(index) {
static_assert(offsetof(TracedNode, class_id_) ==
Internals::kTracedNodeClassIdOffset);
// TracedNode size should stay within 2 words.
static_assert(sizeof(TracedNode) <= (2 * kSystemPointerSize));
DCHECK(!is_in_use());
DCHECK(!is_in_young_list());
DCHECK(!is_root());
DCHECK(!markbit());
index_ = index;
next_free_index_ = next_free_index;
}
// Publishes all internal state to be consumed by other threads.
@ -285,7 +288,8 @@ class TracedNodeBlock final {
: public base::iterator<std::forward_iterator_tag, TracedNode> {
public:
explicit NodeIteratorImpl(TracedNodeBlock* block) : block_(block) {}
NodeIteratorImpl(TracedNodeBlock* block, uint16_t current_index)
NodeIteratorImpl(TracedNodeBlock* block,
TracedNode::IndexType current_index)
: block_(block), current_index_(current_index) {}
NodeIteratorImpl(const NodeIteratorImpl& other) V8_NOEXCEPT
: block_(other.block_),
@ -299,9 +303,7 @@ class TracedNodeBlock final {
return !(*this == rhs);
}
inline NodeIteratorImpl& operator++() {
if (current_index_ < kBlockSize) {
current_index_++;
}
return *this;
}
inline NodeIteratorImpl operator++(int) {
@ -312,7 +314,7 @@ class TracedNodeBlock final {
private:
TracedNodeBlock* block_;
uint16_t current_index_ = 0;
TracedNode::IndexType current_index_ = 0;
};
public:
@ -320,47 +322,100 @@ class TracedNodeBlock final {
using UsableList = DoublyLinkedList<TracedNodeBlock, UsableListNode>;
using Iterator = NodeIteratorImpl;
#if defined(V8_USE_ADDRESS_SANITIZER)
static constexpr size_t kMinCapacity = 1;
static constexpr size_t kMaxCapacity = 1;
#else // !defined(V8_USE_ADDRESS_SANITIZER)
#ifdef V8_HOST_ARCH_64_BIT
static constexpr size_t kMinCapacity = 256;
#else // !V8_HOST_ARCH_64_BIT
static constexpr size_t kMinCapacity = 128;
#endif // !V8_HOST_ARCH_64_BIT
static constexpr size_t kMaxCapacity =
std::numeric_limits<TracedNode::IndexType>::max() - 1;
#endif // !defined(V8_USE_ADDRESS_SANITIZER)
static constexpr TracedNode::IndexType kInvalidFreeListNodeIndex = -1;
static_assert(kMinCapacity <= kMaxCapacity);
static_assert(kInvalidFreeListNodeIndex > kMaxCapacity);
static TracedNodeBlock* Create(TracedHandlesImpl&, OverallList&, UsableList&);
static void Delete(TracedNodeBlock*);
static TracedNodeBlock& From(TracedNode& node);
static const TracedNodeBlock& From(const TracedNode& node);
TracedNodeBlock(TracedHandlesImpl&, OverallList&, UsableList&);
TracedNode* AllocateNode();
void FreeNode(TracedNode*);
TracedNode* at(uint16_t index) { return &nodes_[index]; }
const TracedNode* at(uint16_t index) const {
TracedNode* at(TracedNode::IndexType index) {
return &(reinterpret_cast<TracedNode*>(this + 1)[index]);
}
const TracedNode* at(TracedNode::IndexType index) const {
return const_cast<TracedNodeBlock*>(this)->at(index);
}
const void* nodes_begin_address() const { return at(0); }
const void* nodes_end_address() const { return at(kBlockSize); }
const void* nodes_end_address() const { return at(capacity_); }
TracedHandlesImpl& traced_handles() const { return traced_handles_; }
Iterator begin() { return Iterator(this); }
Iterator end() { return Iterator(this, kBlockSize); }
Iterator end() { return Iterator(this, capacity_); }
bool IsFull() const { return used_ == kBlockSize; }
bool IsFull() const { return used_ == capacity_; }
bool IsEmpty() const { return used_ == 0; }
size_t size_bytes() const {
return sizeof(*this) + capacity_ * sizeof(TracedNode);
}
private:
TracedNode nodes_[kBlockSize];
TracedNodeBlock(TracedHandlesImpl&, OverallList&, UsableList&,
TracedNode::IndexType);
OverallList::ListNode overall_list_node_;
UsableList::ListNode usable_list_node_;
TracedHandlesImpl& traced_handles_;
uint16_t used_ = 0;
uint16_t first_free_node_ = 0;
TracedNode::IndexType used_ = 0;
const TracedNode::IndexType capacity_ = 0;
TracedNode::IndexType first_free_node_ = 0;
};
// static
TracedNodeBlock* TracedNodeBlock::Create(TracedHandlesImpl& traced_handles,
OverallList& overall_list,
UsableList& usable_list) {
static_assert(alignof(TracedNodeBlock) >= alignof(TracedNode));
static_assert(sizeof(TracedNodeBlock) % alignof(TracedNode) == 0,
"TracedNodeBlock size is used to auto-align node FAM storage.");
const size_t min_wanted_size =
sizeof(TracedNodeBlock) +
sizeof(TracedNode) * TracedNodeBlock::kMinCapacity;
const auto raw_result = v8::base::AllocateAtLeast<char>(min_wanted_size);
const size_t capacity = std::min(
(raw_result.count - sizeof(TracedNodeBlock)) / sizeof(TracedNode),
kMaxCapacity);
CHECK_LT(capacity, std::numeric_limits<TracedNode::IndexType>::max());
const auto result = std::make_pair(raw_result.ptr, capacity);
return new (result.first)
TracedNodeBlock(traced_handles, overall_list, usable_list,
static_cast<TracedNode::IndexType>(result.second));
}
// static
void TracedNodeBlock::Delete(TracedNodeBlock* block) { free(block); }
TracedNodeBlock::TracedNodeBlock(TracedHandlesImpl& traced_handles,
OverallList& overall_list,
UsableList& usable_list)
: traced_handles_(traced_handles) {
for (size_t i = 0; i < (kBlockSize - 1); i++) {
nodes_[i].Initialize(i, i + 1);
UsableList& usable_list,
TracedNode::IndexType capacity)
: traced_handles_(traced_handles), capacity_(capacity) {
for (TracedNode::IndexType i = 0; i < (capacity_ - 1); i++) {
new (at(i)) TracedNode(i, i + 1);
}
nodes_[kBlockSize - 1].Initialize(kBlockSize - 1, kInvalidFreeListNodeIndex);
new (at(capacity_ - 1)) TracedNode(capacity_ - 1, kInvalidFreeListNodeIndex);
overall_list.PushFront(this);
usable_list.PushFront(this);
}
@ -368,7 +423,8 @@ TracedNodeBlock::TracedNodeBlock(TracedHandlesImpl& traced_handles,
// static
TracedNodeBlock& TracedNodeBlock::From(TracedNode& node) {
TracedNode* first_node = &node - node.index();
return *reinterpret_cast<TracedNodeBlock*>(first_node);
return *reinterpret_cast<TracedNodeBlock*>(
reinterpret_cast<uintptr_t>(first_node) - sizeof(TracedNodeBlock));
}
// static
@ -377,13 +433,13 @@ const TracedNodeBlock& TracedNodeBlock::From(const TracedNode& node) {
}
TracedNode* TracedNodeBlock::AllocateNode() {
if (used_ == kBlockSize) {
if (used_ == capacity_) {
DCHECK_EQ(first_free_node_, kInvalidFreeListNodeIndex);
return nullptr;
}
DCHECK_NE(first_free_node_, kInvalidFreeListNodeIndex);
auto* node = &nodes_[first_free_node_];
auto* node = at(first_free_node_);
first_free_node_ = node->next_free();
used_++;
DCHECK(!node->is_in_use());
@ -441,13 +497,9 @@ class TracedHandlesImpl final {
void IterateYoung(RootVisitor* visitor);
void IterateYoungRoots(RootVisitor* visitor);
size_t used_node_count() const { return used_; }
size_t total_size_bytes() const {
return sizeof(TracedNode) * kBlockSize *
(blocks_.Size() + empty_blocks_.size() +
empty_block_candidates_.size());
}
size_t used_size_bytes() const { return sizeof(TracedNode) * used_; }
size_t used_node_count() const { return used_nodes_; }
size_t used_size_bytes() const { return sizeof(TracedNode) * used_nodes_; }
size_t total_size_bytes() const { return block_size_bytes_; }
START_ALLOW_USE_DEPRECATED()
@ -472,14 +524,16 @@ class TracedHandlesImpl final {
Isolate* isolate_;
bool is_marking_ = false;
bool is_sweeping_on_mutator_thread_ = false;
size_t used_ = 0;
size_t used_nodes_ = 0;
size_t block_size_bytes_ = 0;
};
TracedNode* TracedHandlesImpl::AllocateNode() {
auto* block = usable_blocks_.Front();
if (!block) {
if (empty_blocks_.empty() && empty_block_candidates_.empty()) {
block = new TracedNodeBlock(*this, blocks_, usable_blocks_);
block = TracedNodeBlock::Create(*this, blocks_, usable_blocks_);
block_size_bytes_ += block->size_bytes();
} else {
// Pick a block from candidates first as such blocks may anyways still be
// referred to from young nodes and thus are not eligible for freeing.
@ -496,7 +550,7 @@ TracedNode* TracedHandlesImpl::AllocateNode() {
}
auto* node = block->AllocateNode();
if (node) {
used_++;
used_nodes_++;
return node;
}
@ -515,23 +569,29 @@ void TracedHandlesImpl::FreeNode(TracedNode* node) {
blocks_.Remove(&block);
empty_block_candidates_.push_back(&block);
}
used_--;
used_nodes_--;
}
TracedHandlesImpl::TracedHandlesImpl(Isolate* isolate) : isolate_(isolate) {}
TracedHandlesImpl::~TracedHandlesImpl() {
size_t block_size_bytes = 0;
while (!blocks_.Empty()) {
auto* block = blocks_.Front();
blocks_.PopFront();
delete block;
block_size_bytes += block->size_bytes();
TracedNodeBlock::Delete(block);
}
for (auto* block : empty_block_candidates_) {
delete block;
block_size_bytes += block->size_bytes();
TracedNodeBlock::Delete(block);
}
for (auto* block : empty_blocks_) {
delete block;
block_size_bytes += block->size_bytes();
TracedNodeBlock::Delete(block);
}
USE(block_size_bytes);
DCHECK_EQ(block_size_bytes, block_size_bytes_);
}
Handle<Object> TracedHandlesImpl::Create(Address value, Address* slot,
@ -693,7 +753,9 @@ void TracedHandlesImpl::DeleteEmptyBlocks() {
for (size_t i = 1; i < empty_blocks_.size(); i++) {
auto* block = empty_blocks_[i];
DCHECK(block->IsEmpty());
delete block;
DCHECK_GE(block_size_bytes_, block->size_bytes());
block_size_bytes_ -= block->size_bytes();
TracedNodeBlock::Delete(block);
}
empty_blocks_.resize(1);
empty_blocks_.shrink_to_fit();