Problem packing repository

For the past 2 weeks, every pull from the mainline kernel repository
has included the following message about "Auto packing" that fails to
complete.

git --version yields "git version 1.6.3.2.198.g6096d"

================================================

Auto packing your repository for optimum performance. You may also
run "git gc" manually. See "git help gc" for more information.
usage: git-pack-objects [{ -q | --progress | --all-progress }]
        [--max-pack-size=N] [--local] [--incremental]
        [--window=N] [--window-memory=N] [--depth=N]
        [--no-reuse-delta] [--no-reuse-object] [--delta-base-offset]
        [--threads=N] [--non-empty] [--revs [--unpacked | --all]*]
[--reflog]
        [--stdout | base-name] [--include-tag]
        [--keep-unreachable | --unpack-unreachable]
        [<ref-list | <object-list]
error: failed to run repack