reproduce (this is a W=1 build):
        git checkout 65058e9e9b20619f920397f529072e853dd43811
        b4 shazam https://lore.kernel.org/r/20260326-umount-kills-nfsv4-state-v5-1-d2ce071b3570@oracle.com

        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash fs/nfsd/