glthread: fix a crash with incorrect glShaderSource parameters

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3948>

diff --git a/src/mesa/main/marshal.c b/src/mesa/main/marshal.c
index 9c9d67208784e3a2c613f853daa3e6c8c4287f7b..b2935f63753aa0486ea172b94ab6ca36155e6717 100644 (file)
--- a/src/mesa/main/marshal.c
+++ b/src/mesa/main/marshal.c
@@ -111,7 +111,7 @@ _mesa_marshal_ShaderSource(GLuint shader, GLsizei count,
       measure_ShaderSource_strings(count, string, length, length_tmp);
    size_t total_cmd_size = fixed_cmd_size + length_size + total_string_length;
 
-   if (total_cmd_size <= MARSHAL_MAX_CMD_SIZE) {
+   if (total_cmd_size <= MARSHAL_MAX_CMD_SIZE && count > 0) {
       struct marshal_cmd_ShaderSource *cmd =
          _mesa_glthread_allocate_command(ctx, DISPATCH_CMD_ShaderSource,
                                          total_cmd_size);