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[asan] Modify ASan metadata atomically. 

We need this to avoid races when ASan and LSan are used together.

llvm-svn: 182252
This commit is contained in:
Sergey Matveev 2013-05-20 11:25:18 +00:00
parent 3c20829559
commit 6a6c5b6dee
1 changed files with 5 additions and 3 deletions
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8
compiler-rt/lib/asan/asan_allocator2.cc
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@ -265,7 +265,7 @@ struct QuarantineCallback {
void Recycle(AsanChunk *m) {
CHECK_EQ(m->chunk_state, CHUNK_QUARANTINE);
m->chunk_state = CHUNK_AVAILABLE;
atomic_store((atomic_uint8_t*)m, CHUNK_AVAILABLE, memory_order_relaxed);
CHECK_NE(m->alloc_tid, kInvalidTid);
CHECK_NE(m->free_tid, kInvalidTid);
PoisonShadow(m->Beg(),
@ -362,7 +362,6 @@ static void *Allocate(uptr size, uptr alignment, StackTrace *stack,
CHECK_LE(user_end, alloc_end);
uptr chunk_beg = user_beg - kChunkHeaderSize;
AsanChunk *m = reinterpret_cast<AsanChunk *>(chunk_beg);
m->chunk_state = CHUNK_ALLOCATED;
m->alloc_type = alloc_type;
m->rz_log = rz_log;
u32 alloc_tid = t ? t->tid() : 0;
@ -419,6 +418,8 @@ static void *Allocate(uptr size, uptr alignment, StackTrace *stack,
uptr fill_size = Min(size, (uptr)fl.max_malloc_fill_size);
REAL(memset)(res, fl.malloc_fill_byte, fill_size);
}
// Must be the last mutation of metadata in this function.
atomic_store((atomic_uint8_t *)m, CHUNK_ALLOCATED, memory_order_release);
ASAN_MALLOC_HOOK(res, size);
return res;
}
@ -432,8 +433,9 @@ static void Deallocate(void *ptr, StackTrace *stack, AllocType alloc_type) {
u8 old_chunk_state = CHUNK_ALLOCATED;
// Flip the chunk_state atomically to avoid race on double-free.
// Must be the first mutation of metadata in this function.
if (!atomic_compare_exchange_strong((atomic_uint8_t*)m, &old_chunk_state,
CHUNK_QUARANTINE, memory_order_relaxed)) {
CHUNK_QUARANTINE, memory_order_acquire)) {
if (old_chunk_state == CHUNK_QUARANTINE)
ReportDoubleFree((uptr)ptr, stack);
else