reproduce:
        git remote add hch-xfs git://git.infradead.org/users/hch/xfs
        git fetch --no-tags hch-xfs xfs-buf-hash
        git checkout 86793f36204d34531f49d904f9d92590dc965c23
        # choose either of the following two methods to reproduce the issue
        # 1. reproduce by kismet
           # install kmax per https://github.com/paulgazz/kmax/blob/master/README.md
           kismet --linux-ksrc=linux --selectees CONFIG_PROVE_LOCKING --selectors CONFIG_DEBUG_NET_SMALL_RTNL -a=openrisc
        # 2. reproduce by make
           cd linux
           # download the config file from the "config:" link in the report, and save it as .config
           make ARCH=openrisc olddefconfig