diff --git a/lldb/include/lldb/Host/File.h b/lldb/include/lldb/Host/File.h
--- a/lldb/include/lldb/Host/File.h
+++ b/lldb/include/lldb/Host/File.h
@@ -389,9 +389,7 @@
 
   ~NativeFile() override { Close(); }
 
-  bool IsValid() const override {
-    return DescriptorIsValid() || StreamIsValid();
-  }
+  bool IsValid() const override;
 
   Status Read(void *buf, size_t &num_bytes) override;
   Status Write(const void *buf, size_t &num_bytes) override;
@@ -417,15 +415,37 @@
   static bool classof(const File *file) { return file->isA(&ID); }
 
 protected:
-  bool DescriptorIsValid() const {
+  struct ValueGuard {
+    ValueGuard(std::mutex &m, bool b) : guard(m, std::adopt_lock), value(b) {}
+    std::lock_guard<std::mutex> guard;
+    bool value;
+    operator bool() { return value; }
+  };
+
+  bool DescriptorIsValidUnlocked() const {
+
     return File::DescriptorIsValid(m_descriptor);
   }
-  bool StreamIsValid() const { return m_stream != kInvalidStream; }
 
-  // Member variables
+  bool StreamIsValidUnlocked() const { return m_stream != kInvalidStream; }
+
+  ValueGuard DescriptorIsValid() const {
+    m_descriptor_mutex.lock();
+    return ValueGuard(m_descriptor_mutex, DescriptorIsValidUnlocked());
+  }
+
+  ValueGuard StreamIsValid() const {
+    m_stream_mutex.lock();
+    return ValueGuard(m_stream_mutex, StreamIsValidUnlocked());
+  }
+
   int m_descriptor;
   bool m_own_descriptor = false;
+  mutable std::mutex m_descriptor_mutex;
+
   FILE *m_stream;
+  mutable std::mutex m_stream_mutex;
+
   OpenOptions m_options{};
   bool m_own_stream = false;
   std::mutex offset_access_mutex;
diff --git a/lldb/source/Host/common/File.cpp b/lldb/source/Host/common/File.cpp
--- a/lldb/source/Host/common/File.cpp
+++ b/lldb/source/Host/common/File.cpp
@@ -219,7 +219,7 @@
 size_t File::PrintfVarArg(const char *format, va_list args) {
   llvm::SmallString<0> s;
   if (VASprintf(s, format, args)) {
-    size_t written = s.size();;
+    size_t written = s.size();
     Write(s.data(), written);
     return written;
   }
@@ -247,15 +247,21 @@
   return file_stats.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO);
 }
 
+bool NativeFile::IsValid() const {
+  std::scoped_lock lock(m_descriptor_mutex, m_stream_mutex);
+  return DescriptorIsValidUnlocked() || StreamIsValidUnlocked();
+}
+
 Expected<File::OpenOptions> NativeFile::GetOptions() const { return m_options; }
 
 int NativeFile::GetDescriptor() const {
-  if (DescriptorIsValid())
+  if (ValueGuard descriptor_guard = DescriptorIsValid()) {
     return m_descriptor;
+  }
 
   // Don't open the file descriptor if we don't need to, just get it from the
   // stream if we have one.
-  if (StreamIsValid()) {
+  if (ValueGuard stream_guard = StreamIsValid()) {
 #if defined(_WIN32)
     return _fileno(m_stream);
 #else
@@ -272,8 +278,9 @@
 }
 
 FILE *NativeFile::GetStream() {
-  if (!StreamIsValid()) {
-    if (DescriptorIsValid()) {
+  ValueGuard stream_guard = StreamIsValid();
+  if (!stream_guard) {
+    if (ValueGuard descriptor_guard = DescriptorIsValid()) {
       auto mode = GetStreamOpenModeFromOptions(m_options);
       if (!mode)
         llvm::consumeError(mode.takeError());
@@ -282,9 +289,9 @@
 // We must duplicate the file descriptor if we don't own it because when you
 // call fdopen, the stream will own the fd
 #ifdef _WIN32
-          m_descriptor = ::_dup(GetDescriptor());
+          m_descriptor = ::_dup(m_descriptor);
 #else
-          m_descriptor = dup(GetDescriptor());
+          m_descriptor = dup(m_descriptor);
 #endif
           m_own_descriptor = true;
         }
@@ -306,8 +313,11 @@
 }
 
 Status NativeFile::Close() {
+  std::scoped_lock lock(m_descriptor_mutex, m_stream_mutex);
+
   Status error;
-  if (StreamIsValid()) {
+
+  if (StreamIsValidUnlocked()) {
     if (m_own_stream) {
       if (::fclose(m_stream) == EOF)
         error.SetErrorToErrno();
@@ -322,15 +332,17 @@
       }
     }
   }
-  if (DescriptorIsValid() && m_own_descriptor) {
+
+  if (DescriptorIsValidUnlocked() && m_own_descriptor) {
     if (::close(m_descriptor) != 0)
       error.SetErrorToErrno();
   }
-  m_descriptor = kInvalidDescriptor;
+
   m_stream = kInvalidStream;
-  m_options = OpenOptions(0);
   m_own_stream = false;
+  m_descriptor = kInvalidDescriptor;
   m_own_descriptor = false;
+  m_options = OpenOptions(0);
   m_is_interactive = eLazyBoolCalculate;
   m_is_real_terminal = eLazyBoolCalculate;
   return error;
@@ -374,7 +386,7 @@
 
 off_t NativeFile::SeekFromStart(off_t offset, Status *error_ptr) {
   off_t result = 0;
-  if (DescriptorIsValid()) {
+  if (ValueGuard descriptor_guard = DescriptorIsValid()) {
     result = ::lseek(m_descriptor, offset, SEEK_SET);
 
     if (error_ptr) {
@@ -383,7 +395,10 @@
       else
         error_ptr->Clear();
     }
-  } else if (StreamIsValid()) {
+    return result;
+  }
+
+  if (ValueGuard stream_guard = StreamIsValid()) {
     result = ::fseek(m_stream, offset, SEEK_SET);
 
     if (error_ptr) {
@@ -392,15 +407,17 @@
       else
         error_ptr->Clear();
     }
-  } else if (error_ptr) {
-    error_ptr->SetErrorString("invalid file handle");
+    return result;
   }
+
+  if (error_ptr)
+    error_ptr->SetErrorString("invalid file handle");
   return result;
 }
 
 off_t NativeFile::SeekFromCurrent(off_t offset, Status *error_ptr) {
   off_t result = -1;
-  if (DescriptorIsValid()) {
+  if (ValueGuard descriptor_guard = DescriptorIsValid()) {
     result = ::lseek(m_descriptor, offset, SEEK_CUR);
 
     if (error_ptr) {
@@ -409,7 +426,10 @@
       else
         error_ptr->Clear();
     }
-  } else if (StreamIsValid()) {
+    return result;
+  }
+
+  if (ValueGuard stream_guard = StreamIsValid()) {
     result = ::fseek(m_stream, offset, SEEK_CUR);
 
     if (error_ptr) {
@@ -418,15 +438,17 @@
       else
         error_ptr->Clear();
     }
-  } else if (error_ptr) {
-    error_ptr->SetErrorString("invalid file handle");
+    return result;
   }
+
+  if (error_ptr)
+    error_ptr->SetErrorString("invalid file handle");
   return result;
 }
 
 off_t NativeFile::SeekFromEnd(off_t offset, Status *error_ptr) {
   off_t result = -1;
-  if (DescriptorIsValid()) {
+  if (ValueGuard descriptor_guard = DescriptorIsValid()) {
     result = ::lseek(m_descriptor, offset, SEEK_END);
 
     if (error_ptr) {
@@ -435,7 +457,10 @@
       else
         error_ptr->Clear();
     }
-  } else if (StreamIsValid()) {
+    return result;
+  }
+
+  if (ValueGuard stream_guard = StreamIsValid()) {
     result = ::fseek(m_stream, offset, SEEK_END);
 
     if (error_ptr) {
@@ -444,26 +469,32 @@
       else
         error_ptr->Clear();
     }
-  } else if (error_ptr) {
-    error_ptr->SetErrorString("invalid file handle");
   }
+
+  if (error_ptr)
+    error_ptr->SetErrorString("invalid file handle");
   return result;
 }
 
 Status NativeFile::Flush() {
   Status error;
-  if (StreamIsValid()) {
+  if (ValueGuard stream_guard = StreamIsValid()) {
     if (llvm::sys::RetryAfterSignal(EOF, ::fflush, m_stream) == EOF)
       error.SetErrorToErrno();
-  } else if (!DescriptorIsValid()) {
-    error.SetErrorString("invalid file handle");
+    return error;
+  }
+
+  {
+    ValueGuard descriptor_guard = DescriptorIsValid();
+    if (!descriptor_guard)
+      error.SetErrorString("invalid file handle");
   }
   return error;
 }
 
 Status NativeFile::Sync() {
   Status error;
-  if (DescriptorIsValid()) {
+  if (ValueGuard descriptor_guard = DescriptorIsValid()) {
 #ifdef _WIN32
     int err = FlushFileBuffers((HANDLE)_get_osfhandle(m_descriptor));
     if (err == 0)
@@ -518,14 +549,18 @@
 #endif
 
   ssize_t bytes_read = -1;
-  if (DescriptorIsValid()) {
-    bytes_read = llvm::sys::RetryAfterSignal(-1, ::read, m_descriptor, buf, num_bytes);
+  if (ValueGuard descriptor_guard = DescriptorIsValid()) {
+    bytes_read =
+        llvm::sys::RetryAfterSignal(-1, ::read, m_descriptor, buf, num_bytes);
     if (bytes_read == -1) {
       error.SetErrorToErrno();
       num_bytes = 0;
     } else
       num_bytes = bytes_read;
-  } else if (StreamIsValid()) {
+    return error;
+  }
+
+  if (ValueGuard file_lock = StreamIsValid()) {
     bytes_read = ::fread(buf, 1, num_bytes, m_stream);
 
     if (bytes_read == 0) {
@@ -536,10 +571,11 @@
       num_bytes = 0;
     } else
       num_bytes = bytes_read;
-  } else {
-    num_bytes = 0;
-    error.SetErrorString("invalid file handle");
+    return error;
   }
+
+  num_bytes = 0;
+  error.SetErrorString("invalid file handle");
   return error;
 }
 
@@ -577,7 +613,7 @@
 #endif
 
   ssize_t bytes_written = -1;
-  if (DescriptorIsValid()) {
+  if (ValueGuard descriptor_guard = DescriptorIsValid()) {
     bytes_written =
         llvm::sys::RetryAfterSignal(-1, ::write, m_descriptor, buf, num_bytes);
     if (bytes_written == -1) {
@@ -585,7 +621,10 @@
       num_bytes = 0;
     } else
       num_bytes = bytes_written;
-  } else if (StreamIsValid()) {
+    return error;
+  }
+
+  if (ValueGuard stream_guard = StreamIsValid()) {
     bytes_written = ::fwrite(buf, 1, num_bytes, m_stream);
 
     if (bytes_written == 0) {
@@ -596,12 +635,11 @@
       num_bytes = 0;
     } else
       num_bytes = bytes_written;
-
-  } else {
-    num_bytes = 0;
-    error.SetErrorString("invalid file handle");
+    return error;
   }
 
+  num_bytes = 0;
+  error.SetErrorString("invalid file handle");
   return error;
 }