diff --git a/runtime/gc/allocator/rosalloc.cc b/runtime/gc/allocator/rosalloc.cc
index d26635f..c66e80d 100644
--- a/runtime/gc/allocator/rosalloc.cc
+++ b/runtime/gc/allocator/rosalloc.cc
@@ -2112,30 +2112,40 @@
     // result in occasionally not releasing pages which we could release.
     byte pm = page_map_[i];
     switch (pm) {
+      case kPageMapReleased:
+        // Fall through.
       case kPageMapEmpty: {
-        // Only lock if we have an empty page since we want to prevent other threads racing in.
+        // This is currently the start of a free page run.
+        // Acquire the lock to prevent other threads racing in and modifying the page map.
         MutexLock mu(self, lock_);
         // Check that it's still empty after we acquired the lock since another thread could have
         // raced in and placed an allocation here.
-        pm = page_map_[i];
-        if (LIKELY(pm == kPageMapEmpty)) {
-          // The start of a free page run. Release pages.
+        if (IsFreePage(i)) {
+          // Free page runs can start with a released page if we coalesced a released page free
+          // page run with an empty page run.
           FreePageRun* fpr = reinterpret_cast<FreePageRun*>(base_ + i * kPageSize);
-          DCHECK(free_page_runs_.find(fpr) != free_page_runs_.end());
-          size_t fpr_size = fpr->ByteSize(this);
-          DCHECK(IsAligned<kPageSize>(fpr_size));
-          byte* start = reinterpret_cast<byte*>(fpr);
-          reclaimed_bytes += ReleasePageRange(start, start + fpr_size);
-          i += fpr_size / kPageSize;
-          DCHECK_LE(i, page_map_size_);
+          // There is a race condition where FreePage can coalesce fpr with the previous
+          // free page run before we acquire lock_. In that case free_page_runs_.find will not find
+          // a run starting at fpr. To handle this race, we skip reclaiming the page range and go
+          // to the next page.
+          if (free_page_runs_.find(fpr) != free_page_runs_.end()) {
+            size_t fpr_size = fpr->ByteSize(this);
+            DCHECK(IsAligned<kPageSize>(fpr_size));
+            byte* start = reinterpret_cast<byte*>(fpr);
+            reclaimed_bytes += ReleasePageRange(start, start + fpr_size);
+            size_t pages = fpr_size / kPageSize;
+            CHECK_GT(pages, 0U) << "Infinite loop probable";
+            i += pages;
+            DCHECK_LE(i, page_map_size_);
+            break;
+          }
         }
-        break;
+        // Fall through.
       }
       case kPageMapLargeObject:      // Fall through.
       case kPageMapLargeObjectPart:  // Fall through.
       case kPageMapRun:              // Fall through.
       case kPageMapRunPart:          // Fall through.
-      case kPageMapReleased:         // Fall through since it is already released.
         ++i;
         break;  // Skip.
       default: