diff --git a/lld/ELF/InputSection.h b/lld/ELF/InputSection.h
--- a/lld/ELF/InputSection.h
+++ b/lld/ELF/InputSection.h
@@ -157,8 +157,7 @@
   }
 
   ArrayRef<uint8_t> data() const {
-    if (uncompressedSize >= 0)
-      uncompress();
+    uncompress();
     return rawData;
   }
 
diff --git a/lld/ELF/InputSection.cpp b/lld/ELF/InputSection.cpp
--- a/lld/ELF/InputSection.cpp
+++ b/lld/ELF/InputSection.cpp
@@ -118,17 +118,24 @@
 void InputSectionBase::uncompress() const {
   size_t size = uncompressedSize;
   char *uncompressedBuf;
+  static std::mutex mu;
   {
-    static std::mutex mu;
     std::lock_guard<std::mutex> lock(mu);
+    if (uncompressedSize < 0)
+      return;
     uncompressedBuf = bAlloc().Allocate<char>(size);
   }
 
   if (Error e = zlib::uncompress(toStringRef(rawData), uncompressedBuf, size))
     fatal(toString(this) +
           ": uncompress failed: " + llvm::toString(std::move(e)));
-  rawData = makeArrayRef((uint8_t *)uncompressedBuf, size);
-  uncompressedSize = -1;
+
+  {
+    std::lock_guard<std::mutex> lock(mu);
+    if (uncompressedSize >= 0)
+      rawData = makeArrayRef((uint8_t *)uncompressedBuf, size);
+    uncompressedSize = -1;
+  }
 }
 
 template <class ELFT> RelsOrRelas<ELFT> InputSectionBase::relsOrRelas() const {