From https://git.kernel.org/pub/scm/linux/kernel/git/will/kvmtool
   d410d9a..1117dbc  master     -> origin/master
GIT_DIR=/home/alex/lsrc/tests/buildroot.git/dl/kvmtool/git/.git git fetch origin -t -f 
GIT_DIR=/home/alex/lsrc/tests/buildroot.git/dl/kvmtool/git/.git git submodule --quiet foreach 'printf "Deregistering submodule \"%s\"\n" "${path}" && cd .. && rm -rf "${path##*/}"' 
GIT_DIR=/home/alex/lsrc/tests/buildroot.git/dl/kvmtool/git/.git git checkout -f -q '1117dbc8ceb21abc6e8cd9861450695995852290' 
warning: refname '1117dbc8ceb21abc6e8cd9861450695995852290' is ambiguous.
Git normally never creates a ref that ends with 40 hex characters
because it will be ignored when you just specify 40-hex. These refs
may be created by mistake. For example,

  git switch -c $br $(git rev-parse ...)

where "$br" is somehow empty and a 40-hex ref is created. Please
examine these refs and maybe delete them. Turn this message off by
running "git config advice.objectNameWarning false"
GIT_DIR=/home/alex/lsrc/tests/buildroot.git/dl/kvmtool/git/.git git clean -ffdx 
ERROR: No hash found for kvmtool-1117dbc8ceb21abc6e8cd9861450695995852290-git4.tar.gz
make[1]: *** [package/pkg-generic.mk:179: /home/alex/lsrc/tests/buildroot.git/builds/arm64/build/kvmtool-1117dbc8ceb21abc6e8cd9861450695995852290/.stamp_downloaded] Error 1
make: *** [Makefile:23: _all] Error 2