diff --git a/src/mesa/main/framebuffer.c b/src/mesa/main/framebuffer.c
index af3c595..eb29bc5 100644
--- a/src/mesa/main/framebuffer.c
+++ b/src/mesa/main/framebuffer.c
@@ -878,8 +878,13 @@ _mesa_dest_buffer_exists(struct gl_context *ctx, GLenum format)
 GLenum
 _mesa_get_color_read_format(struct gl_context *ctx)
 {
-   const GLenum data_type = _mesa_get_format_datatype(
+   GLenum data_type;
+   if (ctx->ReadBuffer != NULL &&  ctx->ReadBuffer->_ColorReadBuffer != NULL) {
+		   data_type = _mesa_get_format_datatype(
                                ctx->ReadBuffer->_ColorReadBuffer->Format);
+   } else {
+	   return 0;
+   }
 
    switch (ctx->ReadBuffer->_ColorReadBuffer->Format) {
    case MESA_FORMAT_ARGB8888:
@@ -902,8 +907,13 @@ _mesa_get_color_read_format(struct gl_context *ctx)
 GLenum
 _mesa_get_color_read_type(struct gl_context *ctx)
 {
-   const GLenum data_type = _mesa_get_format_datatype(
-                               ctx->ReadBuffer->_ColorReadBuffer->Format);
+   GLenum data_type;
+   if (ctx->ReadBuffer != NULL &&  ctx->ReadBuffer->_ColorReadBuffer != NULL) {
+	  data_type = _mesa_get_format_datatype(
+			  ctx->ReadBuffer->_ColorReadBuffer->Format);
+   } else {
+	   return 0;
+   }
 
    switch (ctx->ReadBuffer->_ColorReadBuffer->Format) {
    case MESA_FORMAT_RGB565: