Index: lib/sanitizer_common/sanitizer_coverage_fuchsia.cc
===================================================================
--- lib/sanitizer_common/sanitizer_coverage_fuchsia.cc
+++ lib/sanitizer_common/sanitizer_coverage_fuchsia.cc
@@ -49,7 +49,7 @@
 
 // Collects trace-pc guard coverage.
 // This class relies on zero-initialization.
-class TracePcGuardController {
+class TracePcGuardController final {
  public:
   // For each PC location being tracked, there is a u32 reserved in global
   // data called the "guard".  At startup, we assign each guard slot a
@@ -113,11 +113,11 @@
   // We can always spare the 32G of address space.
   static constexpr size_t MappingSize = sizeof(uptr) << 32;
 
-  BlockingMutex setup_lock_;
-  uptr *array_;
-  u32 next_index_;
-  zx_handle_t vmo_;
-  char vmo_name_[ZX_MAX_NAME_LEN];
+  BlockingMutex setup_lock_{LINKER_INITIALIZED};
+  uptr *array_{};
+  u32 next_index_{};
+  zx_handle_t vmo_{};
+  char vmo_name_[ZX_MAX_NAME_LEN]{};
 
   size_t DataSize() const { return next_index_ * sizeof(uintptr_t); }