Comment 6 for bug 1654708

Some more details....

A posix function in kernel has changed between 4.4.0-57 and 4.4.0-59

./linux-headers-4.4.0-53/include/linux/posix_acl.h:extern int posix_acl_valid(const struct posix_acl *);
./linux-headers-4.4.0-57/include/linux/posix_acl.h:extern int posix_acl_valid(const struct posix_acl *);
./linux-headers-4.4.0-59/include/linux/posix_acl.h:extern int posix_acl_valid(struct user_namespace *, const struct posix_acl *);
./linux-headers-4.4.0-62/include/linux/posix_acl.h:extern int posix_acl_valid(struct user_namespace *, const struct posix_acl *);

The zfs kernel modul is not updated to match these changes.
see: https://fossies.org/diffs/zfs/0.6.5.7_vs_0.6.5.8/module/zfs/zpl_xattr.c-diff.html

I have tried the following:

Replaced all occurrences
   error = posix_acl_valid(acl);
with
   error = posix_acl_valid(ip, acl);
in file:
    /usr/src/zfs-0.6.5.6/module/zfs/zpl_xattr.c

 dkms remove -m zfs -v 0.6.5.6 -k 4.4.0-62-generic
 dkms install --force -m zfs -v 0.6.5.6 -k 4.4.0-62-generic
does compiles now.

System seems to work.