diff --git a/compiler-rt/lib/scudo/standalone/CMakeLists.txt b/compiler-rt/lib/scudo/standalone/CMakeLists.txt
--- a/compiler-rt/lib/scudo/standalone/CMakeLists.txt
+++ b/compiler-rt/lib/scudo/standalone/CMakeLists.txt
@@ -10,9 +10,6 @@
   -g
   -nostdinc++)
 
-# Too many existing bugs, needs cleanup.
-append_list_if(COMPILER_RT_HAS_WNO_FORMAT -Wno-format SCUDO_CFLAGS)
-
 # Remove -stdlib= which is unused when passing -nostdinc++.
 string(REGEX REPLACE "-stdlib=[a-zA-Z+]*" "" CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})
 
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
@@ -164,9 +164,9 @@
       PoppedBlocks += Region->Stats.PoppedBlocks;
       PushedBlocks += Region->Stats.PushedBlocks;
     }
-    Str->append("Stats: SizeClassAllocator64: %zuM mapped (%zuM rss) in %zu "
+    Str->append("Stats: SizeClassAllocator64: %zuM mapped (%uM rss) in %zu "
                 "allocations; remains %zu\n",
-                TotalMapped >> 20, 0, PoppedBlocks,
+                TotalMapped >> 20, 0U, PoppedBlocks,
                 PoppedBlocks - PushedBlocks);
 
     for (uptr I = 0; I < NumClasses; I++)
diff --git a/compiler-rt/lib/scudo/standalone/secondary.h b/compiler-rt/lib/scudo/standalone/secondary.h
--- a/compiler-rt/lib/scudo/standalone/secondary.h
+++ b/compiler-rt/lib/scudo/standalone/secondary.h
@@ -602,12 +602,11 @@
 
 template <typename Config>
 void MapAllocator<Config>::getStats(ScopedString *Str) const {
-  Str->append(
-      "Stats: MapAllocator: allocated %zu times (%zuK), freed %zu times "
-      "(%zuK), remains %zu (%zuK) max %zuM\n",
-      NumberOfAllocs, AllocatedBytes >> 10, NumberOfFrees, FreedBytes >> 10,
-      NumberOfAllocs - NumberOfFrees, (AllocatedBytes - FreedBytes) >> 10,
-      LargestSize >> 20);
+  Str->append("Stats: MapAllocator: allocated %u times (%zuK), freed %u times "
+              "(%zuK), remains %u (%zuK) max %zuM\n",
+              NumberOfAllocs, AllocatedBytes >> 10, NumberOfFrees,
+              FreedBytes >> 10, NumberOfAllocs - NumberOfFrees,
+              (AllocatedBytes - FreedBytes) >> 10, LargestSize >> 20);
 }
 
 } // namespace scudo
diff --git a/compiler-rt/lib/scudo/standalone/size_class_map.h b/compiler-rt/lib/scudo/standalone/size_class_map.h
--- a/compiler-rt/lib/scudo/standalone/size_class_map.h
+++ b/compiler-rt/lib/scudo/standalone/size_class_map.h
@@ -335,8 +335,8 @@
     const uptr L = S ? getMostSignificantSetBitIndex(S) : 0;
     const uptr Cached = SCMap::getMaxCachedHint(S) * S;
     Buffer.append(
-        "C%02zu => S: %zu diff: +%zu %02zu%% L %zu Cached: %zu %zu; id %zu\n",
-        I, S, D, P, L, SCMap::getMaxCachedHint(S), Cached,
+        "C%02zu => S: %zu diff: +%zu %02zu%% L %zu Cached: %u %zu; id %zu\n", I,
+        S, D, P, L, SCMap::getMaxCachedHint(S), Cached,
         SCMap::getClassIdBySize(S));
     TotalCached += Cached;
     PrevS = S;
diff --git a/compiler-rt/lib/scudo/standalone/tests/CMakeLists.txt b/compiler-rt/lib/scudo/standalone/tests/CMakeLists.txt
--- a/compiler-rt/lib/scudo/standalone/tests/CMakeLists.txt
+++ b/compiler-rt/lib/scudo/standalone/tests/CMakeLists.txt
@@ -17,9 +17,6 @@
   # TODO(kostyak): find a way to make -fsized-deallocation work
   -Wno-mismatched-new-delete)
 
-# Too many existing bugs, needs cleanup.
-append_list_if(COMPILER_RT_HAS_WNO_FORMAT -Wno-format SCUDO_UNITTEST_CFLAGS)
-
 if(COMPILER_RT_DEBUG)
   list(APPEND SCUDO_UNITTEST_CFLAGS -DSCUDO_DEBUG=1)
 endif()
diff --git a/compiler-rt/lib/scudo/standalone/wrappers_c.inc b/compiler-rt/lib/scudo/standalone/wrappers_c.inc
--- a/compiler-rt/lib/scudo/standalone/wrappers_c.inc
+++ b/compiler-rt/lib/scudo/standalone/wrappers_c.inc
@@ -226,7 +226,7 @@
   fputs("<malloc version=\"scudo-1\">\n", stream);
   for (scudo::uptr i = 0; i != max_size; ++i)
     if (sizes[i])
-      fprintf(stream, "<alloc size=\"%lu\" count=\"%lu\"/>\n", i, sizes[i]);
+      fprintf(stream, "<alloc size=\"%zu\" count=\"%zu\"/>\n", i, sizes[i]);
   fputs("</malloc>\n", stream);
   SCUDO_PREFIX(free)(sizes);
   return 0;