• Konstantin Khlebnikov's avatar
    ovl: check dentry positiveness in ovl_cleanup_whiteouts() · 84889d49
    Konstantin Khlebnikov authored
    This patch fixes kernel crash at removing directory which contains
    whiteouts from lower layers.
    
    Cache of directory content passed as "list" contains entries from all
    layers, including whiteouts from lower layers. So, lookup in upper dir
    (moved into work at this stage) will return negative entry. Plus this
    cache is filled long before and we can race with external removal.
    
    Example:
     mkdir -p lower0/dir lower1/dir upper work overlay
     touch lower0/dir/a lower0/dir/b
     mknod lower1/dir/a c 0 0
     mount -t overlay none overlay -o lowerdir=lower1:lower0,upperdir=upper,workdir=work
     rm -fr overlay/dir
    Signed-off-by: default avatarKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
    Signed-off-by: default avatarMiklos Szeredi <miklos@szeredi.hu>
    Cc: <stable@vger.kernel.org> # 3.18+
    84889d49
readdir.c 12.4 KB