cppgc: Allow ASAN-safe memset in SetMemoryInaccessible()

The application may itself change ASAN poisoning which conflicts with
the memset() right before poisoning memory.

This is relevant for destructors but also when invoking Resize() on an
object that uses ASAN container annotations. Annotations are hard to
adjust for the embedder as it is not clear upfront whether the call will
succeed.

Bug: chromium:1056170
Change-Id: I7f719e4130ba6149494a45f220a341658970bc6f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2878733
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74431}

BUILD.gn

@@ -5009,6 +5009,7 @@ v8_source_set("cppgc_base") {
     "src/heap/cppgc/marking-visitor.h",
     "src/heap/cppgc/marking-worklists.cc",
     "src/heap/cppgc/marking-worklists.h",
+    "src/heap/cppgc/memory.cc",
     "src/heap/cppgc/memory.h",
     "src/heap/cppgc/metric-recorder.h",
     "src/heap/cppgc/name-trait.cc",

src/heap/cppgc/memory.cc

@@ -0,0 +1,22 @@
+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/heap/cppgc/memory.h"
+
+#include <cstddef>
+
+#include "src/heap/cppgc/globals.h"
+
+namespace cppgc {
+namespace internal {
+
+void NoSanitizeMemset(void* address, char c, size_t bytes) {
+  volatile Address base = reinterpret_cast<Address>(address);
+  for (size_t i = 0; i < bytes; ++i) {
+    base[i] = c;
+  }
+}
+
+}  // namespace internal
+}  // namespace cppgc

src/heap/cppgc/memory.h

@@ -16,6 +16,9 @@
 namespace cppgc {
 namespace internal {
 
+V8_NOINLINE DISABLE_ASAN void NoSanitizeMemset(void* address, char c,
+                                               size_t bytes);
+
 inline void ZapMemory(void* address, size_t size) {
   // The lowest bit of the zapped value should be 0 so that zapped object are
   // never viewed as fully constructed objects.
@@ -53,7 +56,7 @@ V8_INLINE void SetMemoryInaccessible(void* address, size_t size) {
 
 #elif defined(V8_USE_ADDRESS_SANITIZER)
 
-  memset(address, 0, size);
+  NoSanitizeMemset(address, 0, size);
   ASAN_POISON_MEMORY_REGION(address, size);
 
 #elif DEBUG

src/heap/cppgc/sweeper.cc

@@ -161,9 +161,6 @@ class DeferredFinalizationBuilder final {
       result_.unfinalized_objects.push_back({header});
       found_finalizer_ = true;
     } else {
-      // Unmarked memory may have been poisoned. In the non-concurrent case this
-      // is taken care of by finalizing a header.
-      ASAN_UNPOISON_MEMORY_REGION(header, size);
       SetMemoryInaccessible(header, size);
     }
   }

test/unittests/heap/cppgc/sanitizer-unittest.cc

@@ -4,6 +4,7 @@
 
 #include "include/cppgc/allocation.h"
 #include "src/base/macros.h"
+#include "src/base/sanitizer/asan.h"
 #include "test/unittests/heap/cppgc/tests.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -32,5 +33,27 @@ TEST_F(LsanTest, LeakDetectionDoesNotFindMemoryRetainedFromManaged) {
 
 #endif  // LEAK_SANITIZER
 
+#ifdef V8_USE_ADDRESS_SANITIZER
+
+using AsanTest = testing::TestWithHeap;
+
+class ObjectPoisoningInDestructor final
+    : public GarbageCollected<ObjectPoisoningInDestructor> {
+ public:
+  ~ObjectPoisoningInDestructor() {
+    ASAN_POISON_MEMORY_REGION(this, sizeof(ObjectPoisoningInDestructor));
+  }
+  void Trace(cppgc::Visitor*) const {}
+
+  void* dummy{0};
+};
+
+TEST_F(AsanTest, ObjectPoisoningInDestructor) {
+  MakeGarbageCollected<ObjectPoisoningInDestructor>(GetAllocationHandle());
+  PreciseGC();
+}
+
+#endif  // V8_USE_ADDRESS_SANITIZER
+
 }  // namespace internal
 }  // namespace cppgc