//===-- asan_allocator.cc -------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of AddressSanitizer, an address sanity checker.
//
// Implementation of ASan's memory allocator.
// Evey piece of memory (AsanChunk) allocated by the allocator
// has a left redzone of REDZONE bytes and
// a right redzone such that the end of the chunk is aligned by REDZONE
// (i.e. the right redzone is between 0 and REDZONE-1).
// The left redzone is always poisoned.
// The right redzone is poisoned on malloc, the body is poisoned on free.
// Once freed, a chunk is moved to a quarantine (fifo list).
// After quarantine, a chunk is returned to freelists.
//
// The left redzone contains ASan's internal data and the stack trace of
// the malloc call.
// Once freed, the body of the chunk contains the stack trace of the free call.
//
//===----------------------------------------------------------------------===//
#include "asan_allocator.h"
#include "asan_interceptors.h"
#include "asan_internal.h"
#include "asan_lock.h"
#include "asan_mapping.h"
#include "asan_stats.h"
#include "asan_report.h"
#include "asan_thread.h"
#include "asan_thread_registry.h"
#include "sanitizer/asan_interface.h"
#include "sanitizer_common/sanitizer_atomic.h"
#if defined(_WIN32) && !defined(__clang__)
#include <intrin.h>
#endif
namespace __asan {
#define REDZONE ((uptr)(flags()->redzone))
static const uptr kMinAllocSize = REDZONE * 2;
static const u64 kMaxAvailableRam = 128ULL << 30; // 128G
static const uptr kMaxThreadLocalQuarantine = 1 << 20; // 1M
static const uptr kMinMmapSize = (ASAN_LOW_MEMORY) ? 4UL << 17 : 4UL << 20;
static const uptr kMaxSizeForThreadLocalFreeList =
(ASAN_LOW_MEMORY) ? 1 << 15 : 1 << 17;
// Size classes less than kMallocSizeClassStep are powers of two.
// All other size classes are multiples of kMallocSizeClassStep.
static const uptr kMallocSizeClassStepLog = 26;
static const uptr kMallocSizeClassStep = 1UL << kMallocSizeClassStepLog;
static const uptr kMaxAllowedMallocSize =
(__WORDSIZE == 32) ? 3UL << 30 : 8UL << 30;
static inline bool IsAligned(uptr a, uptr alignment) {
return (a & (alignment - 1)) == 0;
}
static inline uptr Log2(uptr x) {
CHECK(IsPowerOfTwo(x));
#if !defined(_WIN32) || defined(__clang__)
return __builtin_ctzl(x);
#elif defined(_WIN64)
unsigned long ret; // NOLINT
_BitScanForward64(&ret, x);
return ret;
#else
unsigned long ret; // NOLINT
_BitScanForward(&ret, x);
return ret;
#endif
}
static inline uptr RoundUpToPowerOfTwo(uptr size) {
CHECK(size);
if (IsPowerOfTwo(size)) return size;
unsigned long up; // NOLINT
#if !defined(_WIN32) || defined(__clang__)
up = __WORDSIZE - 1 - __builtin_clzl(size);
#elif defined(_WIN64)
_BitScanReverse64(&up, size);
#else
_BitScanReverse(&up, size);
#endif
CHECK(size < (1ULL << (up + 1)));
CHECK(size > (1ULL << up));
return 1UL << (up + 1);
}
static inline uptr SizeClassToSize(u8 size_class) {
CHECK(size_class < kNumberOfSizeClasses);
if (size_class <= kMallocSizeClassStepLog) {
return 1UL << size_class;
} else {
return (size_class - kMallocSizeClassStepLog) * kMallocSizeClassStep;
}
}
static inline u8 SizeToSizeClass(uptr size) {
u8 res = 0;
if (size <= kMallocSizeClassStep) {
uptr rounded = RoundUpToPowerOfTwo(size);
res = Log2(rounded);
} else {
res = ((size + kMallocSizeClassStep - 1) / kMallocSizeClassStep)
+ kMallocSizeClassStepLog;
}
CHECK(res < kNumberOfSizeClasses);
CHECK(size <= SizeClassToSize(res));
return res;
}
// Given REDZONE bytes, we need to mark first size bytes
// as addressable and the rest REDZONE-size bytes as unaddressable.
static void PoisonHeapPartialRightRedzone(uptr mem, uptr size) {
CHECK(size <= REDZONE);
CHECK(IsAligned(mem, REDZONE));
CHECK(IsPowerOfTwo(SHADOW_GRANULARITY));
CHECK(IsPowerOfTwo(REDZONE));
CHECK(REDZONE >= SHADOW_GRANULARITY);
PoisonShadowPartialRightRedzone(mem, size, REDZONE,
kAsanHeapRightRedzoneMagic);
}
static u8 *MmapNewPagesAndPoisonShadow(uptr size) {
CHECK(IsAligned(size, kPageSize));
u8 *res = (u8*)MmapOrDie(size, __FUNCTION__);
PoisonShadow((uptr)res, size, kAsanHeapLeftRedzoneMagic);
if (flags()->debug) {
Printf("ASAN_MMAP: [%p, %p)\n", res, res + size);
}
return res;
}
// Every chunk of memory allocated by this allocator can be in one of 3 states:
// CHUNK_AVAILABLE: the chunk is in the free list and ready to be allocated.
// CHUNK_ALLOCATED: the chunk is allocated and not yet freed.
// CHUNK_QUARANTINE: the chunk was freed and put into quarantine zone.
//
// The pseudo state CHUNK_MEMALIGN is used to mark that the address is not
// the beginning of a AsanChunk (in which the actual chunk resides at
// this - this->used_size).
//
// The magic numbers for the enum values are taken randomly.
enum {
CHUNK_AVAILABLE = 0x57,
CHUNK_ALLOCATED = 0x32,
CHUNK_QUARANTINE = 0x19,
CHUNK_MEMALIGN = 0xDC
};
struct ChunkBase {
// First 8 bytes.
uptr chunk_state : 8;
uptr alloc_tid : 24;
uptr size_class : 8;
uptr free_tid : 24;
// Second 8 bytes.
uptr alignment_log : 8;
uptr used_size : FIRST_32_SECOND_64(32, 56); // Size requested by the user.
// This field may overlap with the user area and thus should not
// be used while the chunk is in CHUNK_ALLOCATED state.
AsanChunk *next;
// Typically the beginning of the user-accessible memory is 'this'+REDZONE
// and is also aligned by REDZONE. However, if the memory is allocated
// by memalign, the alignment might be higher and the user-accessible memory
// starts at the first properly aligned address after 'this'.
uptr Beg() { return RoundUpTo((uptr)this + 1, 1 << alignment_log); }
uptr Size() { return SizeClassToSize(size_class); }
u8 SizeClass() { return size_class; }
};
struct AsanChunk: public ChunkBase {
u32 *compressed_alloc_stack() {
return (u32*)((uptr)this + sizeof(ChunkBase));
}
u32 *compressed_free_stack() {
return (u32*)((uptr)this + Max((uptr)REDZONE, (uptr)sizeof(ChunkBase)));
}
// The left redzone after the ChunkBase is given to the alloc stack trace.
uptr compressed_alloc_stack_size() {
if (REDZONE < sizeof(ChunkBase)) return 0;
return (REDZONE - sizeof(ChunkBase)) / sizeof(u32);
}
uptr compressed_free_stack_size() {
if (REDZONE < sizeof(ChunkBase)) return 0;
return (REDZONE) / sizeof(u32);
}
bool AddrIsInside(uptr addr, uptr access_size, uptr *offset) {
if (addr >= Beg() && (addr + access_size) <= (Beg() + used_size)) {
*offset = addr - Beg();
return true;
}
return false;
}
bool AddrIsAtLeft(uptr addr, uptr access_size, uptr *offset) {
if (addr < Beg()) {
*offset = Beg() - addr;
return true;
}
return false;
}
bool AddrIsAtRight(uptr addr, uptr access_size, uptr *offset) {
if (addr + access_size >= Beg() + used_size) {
if (addr <= Beg() + used_size)
*offset = 0;
else
*offset = addr - (Beg() + used_size);
return true;
}
return false;
}
void DescribeAddress(uptr addr, uptr access_size) {
uptr offset;
Printf("%p is located ", (void*)addr);
if (AddrIsInside(addr, access_size, &offset)) {
Printf("%zu bytes inside of", offset);
} else if (AddrIsAtLeft(addr, access_size, &offset)) {
Printf("%zu bytes to the left of", offset);
} else if (AddrIsAtRight(addr, access_size, &offset)) {
Printf("%zu bytes to the right of", offset);
} else {
Printf(" somewhere around (this is AddressSanitizer bug!)");
}
Printf(" %zu-byte region [%p,%p)\n",
used_size, (void*)Beg(), (void*)(Beg() + used_size));
}
};
static AsanChunk *PtrToChunk(uptr ptr) {
AsanChunk *m = (AsanChunk*)(ptr - REDZONE);
if (m->chunk_state == CHUNK_MEMALIGN) {
m = (AsanChunk*)((uptr)m - m->used_size);
}
return m;
}
void AsanChunkFifoList::PushList(AsanChunkFifoList *q) {
CHECK(q->size() > 0);
if (last_) {
CHECK(first_);
CHECK(!last_->next);
last_->next = q->first_;
last_ = q->last_;
} else {
CHECK(!first_);
last_ = q->last_;
first_ = q->first_;
CHECK(first_);
}
CHECK(last_);
CHECK(!last_->next);
size_ += q->size();
q->clear();
}
void AsanChunkFifoList::Push(AsanChunk *n) {
CHECK(n->next == 0);
if (last_) {
CHECK(first_);
CHECK(!last_->next);
last_->next = n;
last_ = n;
} else {
CHECK(!first_);
last_ = first_ = n;
}
size_ += n->Size();
}
// Interesting performance observation: this function takes up to 15% of overal
// allocator time. That's because *first_ has been evicted from cache long time
// ago. Not sure if we can or want to do anything with this.
AsanChunk *AsanChunkFifoList::Pop() {
CHECK(first_);
AsanChunk *res = first_;
first_ = first_->next;
if (first_ == 0)
last_ = 0;
CHECK(size_ >= res->Size());
size_ -= res->Size();
if (last_) {
CHECK(!last_->next);
}
return res;
}
// All pages we ever allocated.
struct PageGroup {
uptr beg;
uptr end;
uptr size_of_chunk;
uptr last_chunk;
bool InRange(uptr addr) {
return addr >= beg && addr < end;
}
};
class MallocInfo {
public:
explicit MallocInfo(LinkerInitialized x) : mu_(x) { }
AsanChunk *AllocateChunks(u8 size_class, uptr n_chunks) {
AsanChunk *m = 0;
AsanChunk **fl = &free_lists_[size_class];
{
ScopedLock lock(&mu_);
for (uptr i = 0; i < n_chunks; i++) {
if (!(*fl)) {
*fl = GetNewChunks(size_class);
}
AsanChunk *t = *fl;
*fl = t->next;
t->next = m;
CHECK(t->chunk_state == CHUNK_AVAILABLE);
m = t;
}
}
return m;
}
void SwallowThreadLocalMallocStorage(AsanThreadLocalMallocStorage *x,
bool eat_free_lists) {
CHECK(flags()->quarantine_size > 0);
ScopedLock lock(&mu_);
AsanChunkFifoList *q = &x->quarantine_;
if (q->size() > 0) {
quarantine_.PushList(q);
while (quarantine_.size() > (uptr)flags()->quarantine_size) {
QuarantinePop();
}
}
if (eat_free_lists) {
for (uptr size_class = 0; size_class < kNumberOfSizeClasses;
size_class++) {
AsanChunk *m = x->free_lists_[size_class];
while (m) {
AsanChunk *t = m->next;
m->next = free_lists_[size_class];
free_lists_[size_class] = m;
m = t;
}
x->free_lists_[size_class] = 0;
}
}
}
void BypassThreadLocalQuarantine(AsanChunk *chunk) {
ScopedLock lock(&mu_);
quarantine_.Push(chunk);
}
AsanChunk *FindMallocedOrFreed(uptr addr, uptr access_size) {
ScopedLock lock(&mu_);
return FindChunkByAddr(addr);
}
uptr AllocationSize(uptr ptr) {
if (!ptr) return 0;
ScopedLock lock(&mu_);
// Make sure this is our chunk and |ptr| actually points to the beginning
// of the allocated memory.
AsanChunk *m = FindChunkByAddr(ptr);
if (!m || m->Beg() != ptr) return 0;
if (m->chunk_state == CHUNK_ALLOCATED) {
return m->used_size;
} else {
return 0;
}
}
void ForceLock() {
mu_.Lock();
}
void ForceUnlock() {
mu_.Unlock();
}
void PrintStatus() {
ScopedLock lock(&mu_);
uptr malloced = 0;
Printf(" MallocInfo: in quarantine: %zu malloced: %zu; ",
quarantine_.size() >> 20, malloced >> 20);
for (uptr j = 1; j < kNumberOfSizeClasses; j++) {
AsanChunk *i = free_lists_[j];
if (!i) continue;
uptr t = 0;
for (; i; i = i->next) {
t += i->Size();
}
Printf("%zu:%zu ", j, t >> 20);
}
Printf("\n");
}
PageGroup *FindPageGroup(uptr addr) {
ScopedLock lock(&mu_);
return FindPageGroupUnlocked(addr);
}
private:
PageGroup *FindPageGroupUnlocked(uptr addr) {
int n = atomic_load(&n_page_groups_, memory_order_relaxed);
// If the page groups are not sorted yet, sort them.
if (n_sorted_page_groups_ < n) {
SortArray((uptr*)page_groups_, n);
n_sorted_page_groups_ = n;
}
// Binary search over the page groups.
int beg = 0, end = n;
while (beg < end) {
int med = (beg + end) / 2;
uptr g = (uptr)page_groups_[med];
if (addr > g) {
// 'g' points to the end of the group, so 'addr'
// may not belong to page_groups_[med] or any previous group.
beg = med + 1;
} else {
// 'addr' may belong to page_groups_[med] or a previous group.
end = med;
}
}
if (beg >= n)
return 0;
PageGroup *g = page_groups_[beg];
CHECK(g);
if (g->InRange(addr))
return g;
return 0;
}
// We have an address between two chunks, and we want to report just one.
AsanChunk *ChooseChunk(uptr addr,
AsanChunk *left_chunk, AsanChunk *right_chunk) {
// Prefer an allocated chunk or a chunk from quarantine.
if (left_chunk->chunk_state == CHUNK_AVAILABLE &&
right_chunk->chunk_state != CHUNK_AVAILABLE)
return right_chunk;
if (right_chunk->chunk_state == CHUNK_AVAILABLE &&
left_chunk->chunk_state != CHUNK_AVAILABLE)
return left_chunk;
// Choose based on offset.
uptr l_offset = 0, r_offset = 0;
CHECK(left_chunk->AddrIsAtRight(addr, 1, &l_offset));
CHECK(right_chunk->AddrIsAtLeft(addr, 1, &r_offset));
if (l_offset < r_offset)
return left_chunk;
return right_chunk;
}
AsanChunk *FindChunkByAddr(uptr addr) {
PageGroup *g = FindPageGroupUnlocked(addr);
if (!g) return 0;
CHECK(g->size_of_chunk);
uptr offset_from_beg = addr - g->beg;
uptr this_chunk_addr = g->beg +
(offset_from_beg / g->size_of_chunk) * g->size_of_chunk;
CHECK(g->InRange(this_chunk_addr));
AsanChunk *m = (AsanChunk*)this_chunk_addr;
CHECK(m->chunk_state == CHUNK_ALLOCATED ||
m->chunk_state == CHUNK_AVAILABLE ||
m->chunk_state == CHUNK_QUARANTINE);
uptr offset = 0;
if (m->AddrIsInside(addr, 1, &offset))
return m;
if (m->AddrIsAtRight(addr, 1, &offset)) {
if (this_chunk_addr == g->last_chunk) // rightmost chunk
return m;
uptr right_chunk_addr = this_chunk_addr + g->size_of_chunk;
CHECK(g->InRange(right_chunk_addr));
return ChooseChunk(addr, m, (AsanChunk*)right_chunk_addr);
} else {
CHECK(m->AddrIsAtLeft(addr, 1, &offset));
if (this_chunk_addr == g->beg) // leftmost chunk
return m;
uptr left_chunk_addr = this_chunk_addr - g->size_of_chunk;
CHECK(g->InRange(left_chunk_addr));
return ChooseChunk(addr, (AsanChunk*)left_chunk_addr, m);
}
}
void QuarantinePop() {
CHECK(quarantine_.size() > 0);
AsanChunk *m = quarantine_.Pop();
CHECK(m);
// if (F_v >= 2) Printf("MallocInfo::pop %p\n", m);
CHECK(m->chunk_state == CHUNK_QUARANTINE);
m->chunk_state = CHUNK_AVAILABLE;
PoisonShadow((uptr)m, m->Size(), kAsanHeapLeftRedzoneMagic);
CHECK(m->alloc_tid >= 0);
CHECK(m->free_tid >= 0);
uptr size_class = m->SizeClass();
m->next = free_lists_[size_class];
free_lists_[size_class] = m;
// Statistics.
AsanStats &thread_stats = asanThreadRegistry().GetCurrentThreadStats();
thread_stats.real_frees++;
thread_stats.really_freed += m->used_size;
thread_stats.really_freed_redzones += m->Size() - m->used_size;
thread_stats.really_freed_by_size[m->SizeClass()]++;
}
// Get a list of newly allocated chunks.
AsanChunk *GetNewChunks(u8 size_class) {
uptr size = SizeClassToSize(size_class);
CHECK(IsPowerOfTwo(kMinMmapSize));
CHECK(size < kMinMmapSize || (size % kMinMmapSize) == 0);
uptr mmap_size = Max(size, kMinMmapSize);
uptr n_chunks = mmap_size / size;
CHECK(n_chunks * size == mmap_size);
if (size < kPageSize) {
// Size is small, just poison the last chunk.
n_chunks--;
} else {
// Size is large, allocate an extra page at right and poison it.
mmap_size += kPageSize;
}
CHECK(n_chunks > 0);
u8 *mem = MmapNewPagesAndPoisonShadow(mmap_size);
// Statistics.
AsanStats &thread_stats = asanThreadRegistry().GetCurrentThreadStats();
thread_stats.mmaps++;
thread_stats.mmaped += mmap_size;
thread_stats.mmaped_by_size[size_class] += n_chunks;
AsanChunk *res = 0;
for (uptr i = 0; i < n_chunks; i++) {
AsanChunk *m = (AsanChunk*)(mem + i * size);
m->chunk_state = CHUNK_AVAILABLE;
m->size_class = size_class;
m->next = res;
res = m;
}
PageGroup *pg = (PageGroup*)(mem + n_chunks * size);
// This memory is already poisoned, no need to poison it again.
pg->beg = (uptr)mem;
pg->end = pg->beg + mmap_size;
pg->size_of_chunk = size;
pg->last_chunk = (uptr)(mem + size * (n_chunks - 1));
int idx = atomic_fetch_add(&n_page_groups_, 1, memory_order_relaxed);
CHECK(idx < (int)ARRAY_SIZE(page_groups_));
page_groups_[idx] = pg;
return res;
}
AsanChunk *free_lists_[kNumberOfSizeClasses];
AsanChunkFifoList quarantine_;
AsanLock mu_;
PageGroup *page_groups_[kMaxAvailableRam / kMinMmapSize];
atomic_uint32_t n_page_groups_;
int n_sorted_page_groups_;
};
static MallocInfo malloc_info(LINKER_INITIALIZED);
void AsanThreadLocalMallocStorage::CommitBack() {
malloc_info.SwallowThreadLocalMallocStorage(this, true);
}
void DescribeHeapAddress(uptr addr, uptr access_size) {
AsanChunk *m = malloc_info.FindMallocedOrFreed(addr, access_size);
if (!m) return;
m->DescribeAddress(addr, access_size);
CHECK(m->alloc_tid >= 0);
AsanThreadSummary *alloc_thread =
asanThreadRegistry().FindByTid(m->alloc_tid);
StackTrace alloc_stack;
StackTrace::UncompressStack(&alloc_stack, m->compressed_alloc_stack(),
m->compressed_alloc_stack_size());
AsanThread *t = asanThreadRegistry().GetCurrent();
CHECK(t);
if (m->free_tid != kInvalidTid) {
AsanThreadSummary *free_thread =
asanThreadRegistry().FindByTid(m->free_tid);
Printf("freed by thread T%d here:\n", free_thread->tid());
StackTrace free_stack;
StackTrace::UncompressStack(&free_stack, m->compressed_free_stack(),
m->compressed_free_stack_size());
PrintStack(&free_stack);
Printf("previously allocated by thread T%d here:\n",
alloc_thread->tid());
PrintStack(&alloc_stack);
DescribeThread(t->summary());
DescribeThread(free_thread);
DescribeThread(alloc_thread);
} else {
Printf("allocated by thread T%d here:\n", alloc_thread->tid());
PrintStack(&alloc_stack);
DescribeThread(t->summary());
DescribeThread(alloc_thread);
}
}
static u8 *Allocate(uptr alignment, uptr size, StackTrace *stack) {
__asan_init();
CHECK(stack);
if (size == 0) {
size = 1; // TODO(kcc): do something smarter
}
CHECK(IsPowerOfTwo(alignment));
uptr rounded_size = RoundUpTo(size, REDZONE);
uptr needed_size = rounded_size + REDZONE;
if (alignment > REDZONE) {
needed_size += alignment;
}
CHECK(IsAligned(needed_size, REDZONE));
if (size > kMaxAllowedMallocSize || needed_size > kMaxAllowedMallocSize) {
Report("WARNING: AddressSanitizer failed to allocate %p bytes\n",
(void*)size);
return 0;
}
u8 size_class = SizeToSizeClass(needed_size);
uptr size_to_allocate = SizeClassToSize(size_class);
CHECK(size_to_allocate >= kMinAllocSize);
CHECK(size_to_allocate >= needed_size);
CHECK(IsAligned(size_to_allocate, REDZONE));
if (flags()->verbosity >= 3) {
Printf("Allocate align: %zu size: %zu class: %u real: %zu\n",
alignment, size, size_class, size_to_allocate);
}
AsanThread *t = asanThreadRegistry().GetCurrent();
AsanStats &thread_stats = asanThreadRegistry().GetCurrentThreadStats();
// Statistics
thread_stats.mallocs++;
thread_stats.malloced += size;
thread_stats.malloced_redzones += size_to_allocate - size;
thread_stats.malloced_by_size[size_class]++;
AsanChunk *m = 0;
if (!t || size_to_allocate >= kMaxSizeForThreadLocalFreeList) {
// get directly from global storage.
m = malloc_info.AllocateChunks(size_class, 1);
thread_stats.malloc_large++;
} else {
// get from the thread-local storage.
AsanChunk **fl = &t->malloc_storage().free_lists_[size_class];
if (!*fl) {
uptr n_new_chunks = kMaxSizeForThreadLocalFreeList / size_to_allocate;
*fl = malloc_info.AllocateChunks(size_class, n_new_chunks);
thread_stats.malloc_small_slow++;
}
m = *fl;
*fl = (*fl)->next;
}
CHECK(m);
CHECK(m->chunk_state == CHUNK_AVAILABLE);
m->chunk_state = CHUNK_ALLOCATED;
m->next = 0;
CHECK(m->Size() == size_to_allocate);
uptr addr = (uptr)m + REDZONE;
CHECK(addr <= (uptr)m->compressed_free_stack());
if (alignment > REDZONE && (addr & (alignment - 1))) {
addr = RoundUpTo(addr, alignment);
CHECK((addr & (alignment - 1)) == 0);
AsanChunk *p = (AsanChunk*)(addr - REDZONE);
p->chunk_state = CHUNK_MEMALIGN;
p->used_size = (uptr)p - (uptr)m;
m->alignment_log = Log2(alignment);
CHECK(m->Beg() == addr);
} else {
m->alignment_log = Log2(REDZONE);
}
CHECK(m == PtrToChunk(addr));
m->used_size = size;
CHECK(m->Beg() == addr);
m->alloc_tid = t ? t->tid() : 0;
m->free_tid = kInvalidTid;
StackTrace::CompressStack(stack, m->compressed_alloc_stack(),
m->compressed_alloc_stack_size());
PoisonShadow(addr, rounded_size, 0);
if (size < rounded_size) {
PoisonHeapPartialRightRedzone(addr + rounded_size - REDZONE,
size & (REDZONE - 1));
}
if (size <= (uptr)(flags()->max_malloc_fill_size)) {
REAL(memset)((void*)addr, 0, rounded_size);
}
return (u8*)addr;
}
static void Deallocate(u8 *ptr, StackTrace *stack) {
if (!ptr) return;
CHECK(stack);
if (flags()->debug) {
CHECK(malloc_info.FindPageGroup((uptr)ptr));
}
// Printf("Deallocate %p\n", ptr);
AsanChunk *m = PtrToChunk((uptr)ptr);
// Flip the chunk_state atomically to avoid race on double-free.
u8 old_chunk_state = atomic_exchange((atomic_uint8_t*)m, CHUNK_QUARANTINE,
memory_order_acq_rel);
if (old_chunk_state == CHUNK_QUARANTINE) {
ReportDoubleFree((uptr)ptr, stack);
} else if (old_chunk_state != CHUNK_ALLOCATED) {
ReportFreeNotMalloced((uptr)ptr, stack);
}
CHECK(old_chunk_state == CHUNK_ALLOCATED);
// With REDZONE==16 m->next is in the user area, otherwise it should be 0.
CHECK(REDZONE <= 16 || !m->next);
CHECK(m->free_tid == kInvalidTid);
CHECK(m->alloc_tid >= 0);
AsanThread *t = asanThreadRegistry().GetCurrent();
m->free_tid = t ? t->tid() : 0;
StackTrace::CompressStack(stack, m->compressed_free_stack(),
m->compressed_free_stack_size());
uptr rounded_size = RoundUpTo(m->used_size, REDZONE);
PoisonShadow((uptr)ptr, rounded_size, kAsanHeapFreeMagic);
// Statistics.
AsanStats &thread_stats = asanThreadRegistry().GetCurrentThreadStats();
thread_stats.frees++;
thread_stats.freed += m->used_size;
thread_stats.freed_by_size[m->SizeClass()]++;
CHECK(m->chunk_state == CHUNK_QUARANTINE);
if (t) {
AsanThreadLocalMallocStorage *ms = &t->malloc_storage();
ms->quarantine_.Push(m);
if (ms->quarantine_.size() > kMaxThreadLocalQuarantine) {
malloc_info.SwallowThreadLocalMallocStorage(ms, false);
}
} else {
malloc_info.BypassThreadLocalQuarantine(m);
}
}
static u8 *Reallocate(u8 *old_ptr, uptr new_size,
StackTrace *stack) {
CHECK(old_ptr && new_size);
// Statistics.
AsanStats &thread_stats = asanThreadRegistry().GetCurrentThreadStats();
thread_stats.reallocs++;
thread_stats.realloced += new_size;
AsanChunk *m = PtrToChunk((uptr)old_ptr);
CHECK(m->chunk_state == CHUNK_ALLOCATED);
uptr old_size = m->used_size;
uptr memcpy_size = Min(new_size, old_size);
u8 *new_ptr = Allocate(0, new_size, stack);
if (new_ptr) {
CHECK(REAL(memcpy) != 0);
REAL(memcpy)(new_ptr, old_ptr, memcpy_size);
Deallocate(old_ptr, stack);
}
return new_ptr;
}
} // namespace __asan
// Default (no-op) implementation of malloc hooks.
extern "C" {
SANITIZER_WEAK_ATTRIBUTE SANITIZER_INTERFACE_ATTRIBUTE
void __asan_malloc_hook(void *ptr, uptr size) {
(void)ptr;
(void)size;
}
SANITIZER_WEAK_ATTRIBUTE SANITIZER_INTERFACE_ATTRIBUTE
void __asan_free_hook(void *ptr) {
(void)ptr;
}
} // extern "C"
namespace __asan {
SANITIZER_INTERFACE_ATTRIBUTE
void *asan_memalign(uptr alignment, uptr size, StackTrace *stack) {
void *ptr = (void*)Allocate(alignment, size, stack);
__asan_malloc_hook(ptr, size);
return ptr;
}
SANITIZER_INTERFACE_ATTRIBUTE
void asan_free(void *ptr, StackTrace *stack) {
__asan_free_hook(ptr);
Deallocate((u8*)ptr, stack);
}
SANITIZER_INTERFACE_ATTRIBUTE
void *asan_malloc(uptr size, StackTrace *stack) {
void *ptr = (void*)Allocate(0, size, stack);
__asan_malloc_hook(ptr, size);
return ptr;
}
void *asan_calloc(uptr nmemb, uptr size, StackTrace *stack) {
void *ptr = (void*)Allocate(0, nmemb * size, stack);
if (ptr)
REAL(memset)(ptr, 0, nmemb * size);
__asan_malloc_hook(ptr, nmemb * size);
return ptr;
}
void *asan_realloc(void *p, uptr size, StackTrace *stack) {
if (p == 0) {
void *ptr = (void*)Allocate(0, size, stack);
__asan_malloc_hook(ptr, size);
return ptr;
} else if (size == 0) {
__asan_free_hook(p);
Deallocate((u8*)p, stack);
return 0;
}
return Reallocate((u8*)p, size, stack);
}
void *asan_valloc(uptr size, StackTrace *stack) {
void *ptr = (void*)Allocate(kPageSize, size, stack);
__asan_malloc_hook(ptr, size);
return ptr;
}
void *asan_pvalloc(uptr size, StackTrace *stack) {
size = RoundUpTo(size, kPageSize);
if (size == 0) {
// pvalloc(0) should allocate one page.
size = kPageSize;
}
void *ptr = (void*)Allocate(kPageSize, size, stack);
__asan_malloc_hook(ptr, size);
return ptr;
}
int asan_posix_memalign(void **memptr, uptr alignment, uptr size,
StackTrace *stack) {
void *ptr = Allocate(alignment, size, stack);
CHECK(IsAligned((uptr)ptr, alignment));
__asan_malloc_hook(ptr, size);
*memptr = ptr;
return 0;
}
uptr asan_malloc_usable_size(void *ptr, StackTrace *stack) {
CHECK(stack);
if (ptr == 0) return 0;
uptr usable_size = malloc_info.AllocationSize((uptr)ptr);
if (flags()->check_malloc_usable_size && (usable_size == 0)) {
ReportMallocUsableSizeNotOwned((uptr)ptr, stack);
}
return usable_size;
}
uptr asan_mz_size(const void *ptr) {
return malloc_info.AllocationSize((uptr)ptr);
}
void asan_mz_force_lock() {
malloc_info.ForceLock();
}
void asan_mz_force_unlock() {
malloc_info.ForceUnlock();
}
// ---------------------- Fake stack-------------------- {{{1
FakeStack::FakeStack() {
CHECK(REAL(memset) != 0);
REAL(memset)(this, 0, sizeof(*this));
}
bool FakeStack::AddrIsInSizeClass(uptr addr, uptr size_class) {
uptr mem = allocated_size_classes_[size_class];
uptr size = ClassMmapSize(size_class);
bool res = mem && addr >= mem && addr < mem + size;
return res;
}
uptr FakeStack::AddrIsInFakeStack(uptr addr) {
for (uptr i = 0; i < kNumberOfSizeClasses; i++) {
if (AddrIsInSizeClass(addr, i)) return allocated_size_classes_[i];
}
return 0;
}
// We may want to compute this during compilation.
inline uptr FakeStack::ComputeSizeClass(uptr alloc_size) {
uptr rounded_size = RoundUpToPowerOfTwo(alloc_size);
uptr log = Log2(rounded_size);
CHECK(alloc_size <= (1UL << log));
if (!(alloc_size > (1UL << (log-1)))) {
Printf("alloc_size %zu log %zu\n", alloc_size, log);
}
CHECK(alloc_size > (1UL << (log-1)));
uptr res = log < kMinStackFrameSizeLog ? 0 : log - kMinStackFrameSizeLog;
CHECK(res < kNumberOfSizeClasses);
CHECK(ClassSize(res) >= rounded_size);
return res;
}
void FakeFrameFifo::FifoPush(FakeFrame *node) {
CHECK(node);
node->next = 0;
if (first_ == 0 && last_ == 0) {
first_ = last_ = node;
} else {
CHECK(first_);
CHECK(last_);
last_->next = node;
last_ = node;
}
}
FakeFrame *FakeFrameFifo::FifoPop() {
CHECK(first_ && last_ && "Exhausted fake stack");
FakeFrame *res = 0;
if (first_ == last_) {
res = first_;
first_ = last_ = 0;
} else {
res = first_;
first_ = first_->next;
}
return res;
}
void FakeStack::Init(uptr stack_size) {
stack_size_ = stack_size;
alive_ = true;
}
void FakeStack::Cleanup() {
alive_ = false;
for (uptr i = 0; i < kNumberOfSizeClasses; i++) {
uptr mem = allocated_size_classes_[i];
if (mem) {
PoisonShadow(mem, ClassMmapSize(i), 0);
allocated_size_classes_[i] = 0;
UnmapOrDie((void*)mem, ClassMmapSize(i));
}
}
}
uptr FakeStack::ClassMmapSize(uptr size_class) {
return RoundUpToPowerOfTwo(stack_size_);
}
void FakeStack::AllocateOneSizeClass(uptr size_class) {
CHECK(ClassMmapSize(size_class) >= kPageSize);
uptr new_mem = (uptr)MmapOrDie(
ClassMmapSize(size_class), __FUNCTION__);
// Printf("T%d new_mem[%zu]: %p-%p mmap %zu\n",
// asanThreadRegistry().GetCurrent()->tid(),
// size_class, new_mem, new_mem + ClassMmapSize(size_class),
// ClassMmapSize(size_class));
uptr i;
for (i = 0; i < ClassMmapSize(size_class);
i += ClassSize(size_class)) {
size_classes_[size_class].FifoPush((FakeFrame*)(new_mem + i));
}
CHECK(i == ClassMmapSize(size_class));
allocated_size_classes_[size_class] = new_mem;
}
uptr FakeStack::AllocateStack(uptr size, uptr real_stack) {
if (!alive_) return real_stack;
CHECK(size <= kMaxStackMallocSize && size > 1);
uptr size_class = ComputeSizeClass(size);
if (!allocated_size_classes_[size_class]) {
AllocateOneSizeClass(size_class);
}
FakeFrame *fake_frame = size_classes_[size_class].FifoPop();
CHECK(fake_frame);
fake_frame->size_minus_one = size - 1;
fake_frame->real_stack = real_stack;
while (FakeFrame *top = call_stack_.top()) {
if (top->real_stack > real_stack) break;
call_stack_.LifoPop();
DeallocateFrame(top);
}
call_stack_.LifoPush(fake_frame);
uptr ptr = (uptr)fake_frame;
PoisonShadow(ptr, size, 0);
return ptr;
}
void FakeStack::DeallocateFrame(FakeFrame *fake_frame) {
CHECK(alive_);
uptr size = fake_frame->size_minus_one + 1;
uptr size_class = ComputeSizeClass(size);
CHECK(allocated_size_classes_[size_class]);
uptr ptr = (uptr)fake_frame;
CHECK(AddrIsInSizeClass(ptr, size_class));
CHECK(AddrIsInSizeClass(ptr + size - 1, size_class));
size_classes_[size_class].FifoPush(fake_frame);
}
void FakeStack::OnFree(uptr ptr, uptr size, uptr real_stack) {
FakeFrame *fake_frame = (FakeFrame*)ptr;
CHECK(fake_frame->magic = kRetiredStackFrameMagic);
CHECK(fake_frame->descr != 0);
CHECK(fake_frame->size_minus_one == size - 1);
PoisonShadow(ptr, size, kAsanStackAfterReturnMagic);
}
} // namespace __asan
// ---------------------- Interface ---------------- {{{1
using namespace __asan; // NOLINT
uptr __asan_stack_malloc(uptr size, uptr real_stack) {
if (!flags()->use_fake_stack) return real_stack;
AsanThread *t = asanThreadRegistry().GetCurrent();
if (!t) {
// TSD is gone, use the real stack.
return real_stack;
}
uptr ptr = t->fake_stack().AllocateStack(size, real_stack);
// Printf("__asan_stack_malloc %p %zu %p\n", ptr, size, real_stack);
return ptr;
}
void __asan_stack_free(uptr ptr, uptr size, uptr real_stack) {
if (!flags()->use_fake_stack) return;
if (ptr != real_stack) {
FakeStack::OnFree(ptr, size, real_stack);
}
}
// ASan allocator doesn't reserve extra bytes, so normally we would
// just return "size".
uptr __asan_get_estimated_allocated_size(uptr size) {
if (size == 0) return 1;
return Min(size, kMaxAllowedMallocSize);
}
bool __asan_get_ownership(const void *p) {
return malloc_info.AllocationSize((uptr)p) > 0;
}
uptr __asan_get_allocated_size(const void *p) {
if (p == 0) return 0;
uptr allocated_size = malloc_info.AllocationSize((uptr)p);
// Die if p is not malloced or if it is already freed.
if (allocated_size == 0) {
GET_STACK_TRACE_HERE(kStackTraceMax);
ReportAsanGetAllocatedSizeNotOwned((uptr)p, &stack);
}
return allocated_size;
}