Merge "[WIP] Fix a rosalloc verification crash."

2 files changed, 10 insertions, 5 deletions

diff --git a/runtime/gc/collector/semi_space.cc b/runtime/gc/collector/semi_space.cc
index cb9f111058..681bfaac83 100644
--- a/runtime/gc/collector/semi_space.cc
+++ b/runtime/gc/collector/semi_space.cc
@@ -251,10 +251,13 @@ void SemiSpace::MarkingPhase() {
   // Note: Freed bytes can be negative if we copy form a compacted space to a free-list backed
   // space.
   RecordFree(ObjectBytePair(from_objects - to_objects, from_bytes - to_bytes));
-  // Clear and protect the from space.
+  // Clear the from space. Protect it with PROT_READ here and if
+  // kProtectFromSpace is true, will protect it with PROT_NONE later
+  // in FinishPhase() so the rosalloc verification works (can read the
+  // metadata magic number.)
   from_space_->Clear();
-  VLOG(heap) << "Protecting from_space_: " << *from_space_;
-  from_space_->GetMemMap()->Protect(kProtectFromSpace ? PROT_NONE : PROT_READ);
+  VLOG(heap) << "Protecting from_space_ with PROT_READ : " << *from_space_;
+  from_space_->GetMemMap()->Protect(PROT_READ);
   heap_->PreSweepingGcVerification(this);
   if (swap_semi_spaces_) {
     heap_->SwapSemiSpaces();
@@ -749,6 +752,10 @@ void SemiSpace::SetFromSpace(space::ContinuousMemMapAllocSpace* from_space) {
 
 void SemiSpace::FinishPhase() {
   TimingLogger::ScopedTiming t(__FUNCTION__, GetTimings());
+  if (kProtectFromSpace) {
+    VLOG(heap) << "Protecting from_space_ with PROT_NONE : " << *from_space_;
+    from_space_->GetMemMap()->Protect(PROT_NONE);
+  }
   // Null the "to" and "from" spaces since compacting from one to the other isn't valid until
   // further action is done by the heap.
   to_space_ = nullptr;
diff --git a/runtime/gc/heap.cc b/runtime/gc/heap.cc
index db287d3436..618f1cc220 100644
--- a/runtime/gc/heap.cc
+++ b/runtime/gc/heap.cc
@@ -1592,8 +1592,6 @@ HomogeneousSpaceCompactResult Heap::PerformHomogeneousSpaceCompact() {
   // Make sure that we will have enough room to copy.
   CHECK_GE(to_space->GetFootprintLimit(), from_space->GetFootprintLimit());
   Compact(to_space, from_space, kGcCauseHomogeneousSpaceCompact);
-  // Leave as prot read so that we can still run ROSAlloc verification on this space.
-  from_space->GetMemMap()->Protect(PROT_READ);
   const uint64_t space_size_after_compaction = to_space->Size();
   main_space_ = to_space;
   main_space_backup_.reset(from_space);