diff --git a/compiler-rt/lib/scudo/standalone/primary32.h b/compiler-rt/lib/scudo/standalone/primary32.h
--- a/compiler-rt/lib/scudo/standalone/primary32.h
+++ b/compiler-rt/lib/scudo/standalone/primary32.h
@@ -109,12 +109,46 @@
     }
 
     ScopedLock L(ByteMapMutex);
-    for (uptr I = MinRegionIndex; I < MaxRegionIndex; I++)
+    for (uptr I = MinRegionIndex; I <= MaxRegionIndex; I++)
       if (PossibleRegions[I])
         unmap(reinterpret_cast<void *>(I * RegionSize), RegionSize);
     PossibleRegions.unmapTestOnly();
   }
 
+  // When all blocks are freed, it has to be the same size as `AllocatedUser`.
+  void verifyAllBlocksAreReleasedTestOnly() {
+    // `BatchGroup` and `TransferBatch` also use the blocks from BatchClass.
+    uptr BatchClassUsedInFreeLists = 0;
+    for (uptr I = 0; I < NumClasses; I++) {
+      // We have to count BatchClassUsedInFreeLists in other regions first.
+      if (I == SizeClassMap::BatchClassId)
+        continue;
+      SizeClassInfo *Sci = getSizeClassInfo(I);
+      ScopedLock L1(Sci->Mutex);
+      uptr TotalBlocks = 0;
+      for (BatchGroup &BG : Sci->FreeListInfo.BlockList) {
+        // `BG::Batches` are `TransferBatches`. +1 for `BatchGroup`.
+        BatchClassUsedInFreeLists += BG.Batches.size() + 1;
+        for (const auto &It : BG.Batches)
+          TotalBlocks += It.getCount();
+      }
+
+      const uptr BlockSize = getSizeByClassId(I);
+      DCHECK_EQ(TotalBlocks, Sci->AllocatedUser / BlockSize);
+    }
+
+    SizeClassInfo *Sci = getSizeClassInfo(SizeClassMap::BatchClassId);
+    ScopedLock L1(Sci->Mutex);
+    uptr TotalBlocks = 0;
+    for (BatchGroup &BG : Sci->FreeListInfo.BlockList)
+      for (const auto &It : BG.Batches)
+        TotalBlocks += It.getCount();
+
+    const uptr BlockSize = getSizeByClassId(SizeClassMap::BatchClassId);
+    DCHECK_EQ(TotalBlocks + BatchClassUsedInFreeLists,
+              Sci->AllocatedUser / BlockSize);
+  }
+
   CompactPtrT compactPtr(UNUSED uptr ClassId, uptr Ptr) const {
     return static_cast<CompactPtrT>(Ptr);
   }
diff --git a/compiler-rt/lib/scudo/standalone/primary64.h b/compiler-rt/lib/scudo/standalone/primary64.h
--- a/compiler-rt/lib/scudo/standalone/primary64.h
+++ b/compiler-rt/lib/scudo/standalone/primary64.h
@@ -152,6 +152,41 @@
     PrimaryBase = 0U;
   }
 
+  // When all blocks are freed, it has to be the same size as `AllocatedUser`.
+  void verifyAllBlocksAreReleasedTestOnly() {
+    // `BatchGroup` and `TransferBatch` also use the blocks from BatchClass.
+    uptr BatchClassUsedInFreeLists = 0;
+    for (uptr I = 0; I < NumClasses; I++) {
+      // We have to count BatchClassUsedInFreeLists in other regions first.
+      if (I == SizeClassMap::BatchClassId)
+        continue;
+      RegionInfo *Region = getRegionInfo(I);
+      ScopedLock ML(Region->MMLock);
+      ScopedLock FL(Region->FLLock);
+      const uptr BlockSize = getSizeByClassId(I);
+      uptr TotalBlocks = 0;
+      for (BatchGroup &BG : Region->FreeListInfo.BlockList) {
+        // `BG::Batches` are `TransferBatches`. +1 for `BatchGroup`.
+        BatchClassUsedInFreeLists += BG.Batches.size() + 1;
+        for (const auto &It : BG.Batches)
+          TotalBlocks += It.getCount();
+      }
+
+      DCHECK_EQ(TotalBlocks, Region->MemMapInfo.AllocatedUser / BlockSize);
+    }
+
+    RegionInfo *Region = getRegionInfo(SizeClassMap::BatchClassId);
+    ScopedLock ML(Region->MMLock);
+    ScopedLock FL(Region->FLLock);
+    const uptr BlockSize = getSizeByClassId(SizeClassMap::BatchClassId);
+    uptr TotalBlocks = 0;
+    for (BatchGroup &BG : Region->FreeListInfo.BlockList)
+      for (const auto &It : BG.Batches)
+        TotalBlocks += It.getCount();
+    DCHECK_EQ(TotalBlocks + BatchClassUsedInFreeLists,
+              Region->MemMapInfo.AllocatedUser / BlockSize);
+  }
+
   TransferBatch *popBatch(CacheT *C, uptr ClassId) {
     DCHECK_LT(ClassId, NumClasses);
     RegionInfo *Region = getRegionInfo(ClassId);
diff --git a/compiler-rt/lib/scudo/standalone/tests/primary_test.cpp b/compiler-rt/lib/scudo/standalone/tests/primary_test.cpp
--- a/compiler-rt/lib/scudo/standalone/tests/primary_test.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/primary_test.cpp
@@ -116,7 +116,10 @@
 
 template <template <typename> class BaseConfig, typename SizeClassMapT>
 struct TestAllocator : public SizeClassAllocator<BaseConfig, SizeClassMapT> {
-  ~TestAllocator() { this->unmapTestOnly(); }
+  ~TestAllocator() {
+    this->verifyAllBlocksAreReleasedTestOnly();
+    this->unmapTestOnly();
+  }
 
   void *operator new(size_t size) {
     void *p = nullptr;
@@ -286,7 +289,7 @@
   std::condition_variable Cv;
   bool Ready = false;
   std::thread Threads[32];
-  for (scudo::uptr I = 0; I < ARRAY_SIZE(Threads); I++)
+  for (scudo::uptr I = 0; I < ARRAY_SIZE(Threads); I++) {
     Threads[I] = std::thread([&]() {
       static thread_local typename Primary::CacheT Cache;
       Cache.init(nullptr, Allocator.get());
@@ -312,6 +315,7 @@
       }
       Cache.destroy(nullptr);
     });
+  }
   {
     std::unique_lock<std::mutex> Lock(Mutex);
     Ready = true;
@@ -386,4 +390,10 @@
   EXPECT_LE(*std::max_element(Blocks.begin(), Blocks.end()) -
                 *std::min_element(Blocks.begin(), Blocks.end()),
             GroupSizeMem * 2);
+
+  while (!Blocks.empty()) {
+    Cache.deallocate(ClassId, reinterpret_cast<void *>(Blocks.back()));
+    Blocks.pop_back();
+  }
+  Cache.drain();
 }