reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git/commit/?id=e6977554ceb7b5fc6330f01ac4e7551a0b0109de
        git remote add rostedt-trace https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
        git fetch --no-tags rostedt-trace trace/ring-buffer-prealloc
        git checkout e6977554ceb7b5fc6330f01ac4e7551a0b0109de
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash kernel/trace/