BUG_ON would be better.

This issue was detected with the help of Coccinelle.
Reported-by: NZeal robot <zealci@zte.com.cn>
Reviewed-by: NLukas Czerner <lczerner@redhat.com>
Signed-off-by: Nxu xin <xu.xin16@zte.com.cn>
Link: https://lore.kernel.org/r/20211228073252.580296-1-xu.xin16@zte.com.cnSigned-off-by: NTheodore Ts'o <tytso@mit.edu>