Oilpan: In ASan, poison all unmarked objects before start sweeping

Source/platform/heap/Heap.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 560 matching lines @@
     for (BasePage* page = m_firstPage; page; page = page->next()) {
         page->setTerminating();
     }
 }
 
 void BaseHeap::prepareForSweep()
 {
     ASSERT(!threadState()->isInGC());
     ASSERT(!m_firstUnsweptPage);
 
+#if defined(ADDRESS_SANITIZER)
+    for (BasePage* page = m_firstPage; page; page = page->next()) {
+        page->poisonUnmarkedObjects();
+    }
+#endif
+
     // Move all pages to a list of unswept pages.
     m_firstUnsweptPage = m_firstPage;
     m_firstPage = nullptr;
 }
 
 Address BaseHeap::lazySweep(size_t allocationSize, size_t gcInfoIndex)
 {
     // If there are no pages to be swept, return immediately.
     if (!m_firstUnsweptPage)
         return nullptr;
@@ skipping 908 matching lines @@
         }
         header->checkHeader();
 
         if (!header->isMarked()) {
             size_t size = header->size();
             // This is a fast version of header->payloadSize().
             size_t payloadSize = size - sizeof(HeapObjectHeader);
             Address payload = header->payload();
             // For ASan we unpoison the specific object when calling the
             // finalizer and poison it again when done to allow the object's own
-            // finalizer to operate on the object, but not have other finalizers
-            // be allowed to access it.
+            // finalizer to operate on the object. Given all other unmarked
+            // objects are poisoned, ASan will detech an error if the finalizer

[sof, 2015/04/28 09:15:25]

nit: s/detech/detect/

+            // touches any other on-heap object that die at the same GC cycle.
             ASAN_UNPOISON_MEMORY_REGION(payload, payloadSize);
             header->finalize(payload, payloadSize);
             // This memory will be added to the freelist. Maintain the invariant
             // that memory on the freelist is zero filled.
             FILL_ZERO_IF_PRODUCTION(headerAddress, size);
             ASAN_POISON_MEMORY_REGION(payload, payloadSize);
             headerAddress += size;
             continue;
         }
 
@@ skipping 29 matching lines @@
             markedObjectSize += header->size();
         } else {
             header->markDead();
         }
         headerAddress += header->size();
     }
     if (markedObjectSize)
         Heap::increaseMarkedObjectSize(markedObjectSize);
 }
 
+#if defined(ADDRESS_SANITIZER)
+void NormalPage::poisonUnmarkedObjects()
+{
+    for (Address headerAddress = payload(); headerAddress < payloadEnd();) {
+        HeapObjectHeader* header = reinterpret_cast<HeapObjectHeader*>(headerAddress);
+        ASSERT(header->size() < blinkPagePayloadSize());
+        // Check if a free list entry first since we cannot call
+        // isMarked on a free list entry.
+        if (header->isFree()) {
+            headerAddress += header->size();
+            continue;
+        }
+        header->checkHeader();
+        if (!header->isMarked()) {
+            ASAN_POISON_MEMORY_REGION(header->payload(), header->payloadSize());
+        }
+        headerAddress += header->size();
+    }
+}
+#endif
+
 void NormalPage::populateObjectStartBitMap()
 {
     memset(&m_objectStartBitMap, 0, objectStartBitMapSize);
     Address start = payload();
     for (Address headerAddress = start; headerAddress < payloadEnd();) {
         HeapObjectHeader* header = reinterpret_cast<HeapObjectHeader*>(headerAddress);
         size_t objectOffset = headerAddress - start;
         ASSERT(!(objectOffset & allocationMask));
         size_t objectStartNumber = objectOffset / allocationGranularity;
         size_t mapIndex = objectStartNumber / 8;
@@ skipping 246 matching lines @@
 {
     HeapObjectHeader* header = heapObjectHeader();
     if (header->isMarked()) {
         header->unmark();
         Heap::increaseMarkedObjectSize(size());
     } else {
         header->markDead();
     }
 }
 
+#if defined(ADDRESS_SANITIZER)
+void LargeObjectPage::poisonUnmarkedObjects()
+{
+    HeapObjectHeader* header = heapObjectHeader();
+    if (!header->isMarked())
+        ASAN_POISON_MEMORY_REGION(header->payload(), header->payloadSize());
+}
+#endif
+
 void LargeObjectPage::checkAndMarkPointer(Visitor* visitor, Address address)
 {
     ASSERT(contains(address));
     if (!containedInObjectPayload(address) || heapObjectHeader()->isDead())
         return;
 #if ENABLE(GC_PROFILING)
     visitor->setHostInfo(&address, "stack");
 #endif
     markPointer(visitor, heapObjectHeader());
 }
@@ skipping 852 matching lines @@
 size_t Heap::s_allocatedObjectSize = 0;
 size_t Heap::s_allocatedSpace = 0;
 size_t Heap::s_markedObjectSize = 0;
 // We don't want to use 0 KB for the initial value because it may end up
 // triggering the first GC of some thread too prematurely.
 size_t Heap::s_estimatedLiveObjectSize = 512 * 1024;
 size_t Heap::s_externalObjectSizeAtLastGC = 0;
 double Heap::s_estimatedMarkingTimePerByte = 0.0;
 
 } // namespace blink