[vm/gc] Hold lock before accessing PageSpace::large_pages_

mkustermann · commit-bot@chromium.org · commit fac682c5efb9 · 2019-08-02T15:26:01.000Z
Change-Id: I08c4d125e929f0c1824204b813920ac8a7cf1f59 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/111721 Reviewed-by: Ryan Macnak <rmacnak@google.com> Commit-Queue: Martin Kustermann <kustermann@google.com>
diff --git a/runtime/vm/heap/pages.cc b/runtime/vm/heap/pages.cc
@@ -346,15 +346,19 @@ HeapPage* PageSpace::AllocateLargePage(intptr_t size, HeapPage::PageType type) {
   Heap::RegionName(heap_, is_exec ? Heap::kCode : Heap::kOld, vm_name,
                    kVmNameSize);
   HeapPage* page = HeapPage::Allocate(page_size_in_words, type, vm_name);
-  if (page == NULL) {
-    IncreaseCapacityInWords(-page_size_in_words);
-    return NULL;
+  {
+    MutexLocker ml(&pages_lock_);
+    if (page == nullptr) {
+      IncreaseCapacityInWordsLocked(-page_size_in_words);
+      return nullptr;
+    }
+    page->set_next(large_pages_);
+    large_pages_ = page;
+
+    // Only one object in this page (at least until String::MakeExternal or
+    // Array::MakeFixedLength is called).
+    page->set_object_end(page->object_start() + size);
   }
-  page->set_next(large_pages_);
-  large_pages_ = page;
-  // Only one object in this page (at least until String::MakeExternal or
-  // Array::MakeFixedLength is called).
-  page->set_object_end(page->object_start() + size);
   return page;
 }
 
