reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git/commit/?id=8819d80f6f450d6e21212edc91d44554e4506df6
        git remote add jfern https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git
        git fetch --no-tags jfern rcu/irq-exit-v2-no-task
        git checkout 8819d80f6f450d6e21212edc91d44554e4506df6
        # 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/