diff --git a/runtime/gc/collector_type.h b/runtime/gc/collector_type.h
index 7014357..eef4fba 100644
--- a/runtime/gc/collector_type.h
+++ b/runtime/gc/collector_type.h
@@ -55,6 +55,8 @@
   kCollectorTypeClassLinker,
   // JIT Code cache fake collector.
   kCollectorTypeJitCodeCache,
+  // Hprof fake collector.
+  kCollectorTypeHprof,
   // Fake collector for installing/removing a system-weak holder.
   kCollectorTypeAddRemoveSystemWeakHolder,
 };
diff --git a/runtime/gc/gc_cause.cc b/runtime/gc/gc_cause.cc
index 7ff845d..9e34346 100644
--- a/runtime/gc/gc_cause.cc
+++ b/runtime/gc/gc_cause.cc
@@ -39,6 +39,7 @@
     case kGcCauseClassLinker: return "ClassLinker";
     case kGcCauseJitCodeCache: return "JitCodeCache";
     case kGcCauseAddRemoveSystemWeakHolder: return "SystemWeakHolder";
+    case kGcCauseHprof: return "Hprof";
   }
   LOG(FATAL) << "Unreachable";
   UNREACHABLE();
diff --git a/runtime/gc/gc_cause.h b/runtime/gc/gc_cause.h
index f54f0e4..9b285b1 100644
--- a/runtime/gc/gc_cause.h
+++ b/runtime/gc/gc_cause.h
@@ -53,6 +53,8 @@
   kGcCauseJitCodeCache,
   // Not a real GC cause, used to add or remove system-weak holders.
   kGcCauseAddRemoveSystemWeakHolder,
+  // Not a real GC cause, used to hprof running in the middle of GC.
+  kGcCauseHprof,
 };
 
 const char* PrettyCause(GcCause cause);
diff --git a/runtime/gc/heap.cc b/runtime/gc/heap.cc
index 0a45fce..a78de37 100644
--- a/runtime/gc/heap.cc
+++ b/runtime/gc/heap.cc
@@ -987,7 +987,9 @@
     // Continuous spaces don't necessarily have bitmaps.
     accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap();
     accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap();
-    if (live_bitmap != nullptr) {
+    // The region space bitmap is not added since VisitObjects visits the region space objects with
+    // special handling.
+    if (live_bitmap != nullptr && !space->IsRegionSpace()) {
       CHECK(mark_bitmap != nullptr);
       live_bitmap_->AddContinuousSpaceBitmap(live_bitmap);
       mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap);
@@ -1028,7 +1030,7 @@
     // Continuous spaces don't necessarily have bitmaps.
     accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap();
     accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap();
-    if (live_bitmap != nullptr) {
+    if (live_bitmap != nullptr && !space->IsRegionSpace()) {
       DCHECK(mark_bitmap != nullptr);
       live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap);
       mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap);
diff --git a/runtime/hprof/hprof.cc b/runtime/hprof/hprof.cc
index 133502e..e59c4bb 100644
--- a/runtime/hprof/hprof.cc
+++ b/runtime/hprof/hprof.cc
@@ -50,6 +50,7 @@
 #include "gc_root.h"
 #include "gc/accounting/heap_bitmap.h"
 #include "gc/allocation_record.h"
+#include "gc/scoped_gc_critical_section.h"
 #include "gc/heap.h"
 #include "gc/space/space.h"
 #include "globals.h"
@@ -463,6 +464,7 @@
     }
 
     bool okay;
+    visited_objects_.clear();
     if (direct_to_ddms_) {
       if (kDirectStream) {
         okay = DumpToDdmsDirect(overall_size, max_length, CHUNK_TYPE("HPDS"));
@@ -911,6 +913,9 @@
   // bits.
   std::unordered_set<uint64_t> simple_roots_;
 
+  // To make sure we don't dump the same object multiple times. b/34967844
+  std::unordered_set<mirror::Object*> visited_objects_;
+
   friend class GcRootVisitor;
   DISALLOW_COPY_AND_ASSIGN(Hprof);
 };
@@ -1093,6 +1098,7 @@
   if (obj->IsClass() && obj->AsClass()->IsRetired()) {
     return;
   }
+  DCHECK(visited_objects_.insert(obj).second) << "Already visited " << obj;
 
   ++total_objects_;
 
@@ -1444,22 +1450,15 @@
 // Otherwise, "filename" is used to create an output file.
 void DumpHeap(const char* filename, int fd, bool direct_to_ddms) {
   CHECK(filename != nullptr);
-
   Thread* self = Thread::Current();
-  gc::Heap* heap = Runtime::Current()->GetHeap();
-  if (heap->IsGcConcurrentAndMoving()) {
-    // Need to take a heap dump while GC isn't running. See the
-    // comment in Heap::VisitObjects().
-    heap->IncrementDisableMovingGC(self);
-  }
-  {
-    ScopedSuspendAll ssa(__FUNCTION__, true /* long suspend */);
-    Hprof hprof(filename, fd, direct_to_ddms);
-    hprof.Dump();
-  }
-  if (heap->IsGcConcurrentAndMoving()) {
-    heap->DecrementDisableMovingGC(self);
-  }
+  // Need to take a heap dump while GC isn't running. See the comment in Heap::VisitObjects().
+  // Also we need the critical section to avoid visiting the same object twice. See b/34967844
+  gc::ScopedGCCriticalSection gcs(self,
+                                  gc::kGcCauseHprof,
+                                  gc::kCollectorTypeHprof);
+  ScopedSuspendAll ssa(__FUNCTION__, true /* long suspend */);
+  Hprof hprof(filename, fd, direct_to_ddms);
+  hprof.Dump();
 }
 
 }  // namespace hprof