su -s <TAB> completion depends on "chsh -l" present in the
util-linux implementation of chsh. But SUSE uses chsh from shadow
package that does not include this feature. Use /etc/shells
instead.

--- util-linux/bash-completion/su
+++ util-linux/bash-completion/su
@@ -14,7 +14,7 @@ _su_module()
 			return 0
 			;;
 		'-s'|'--shell')
-			COMPREPLY=( $(compgen -W "$(chsh -l)" -- $cur) )
+			COMPREPLY=( $(compgen -W "$(</etc/shells)" -- $cur) )
 			return 0
 			;;
 		'-h'|'--help'|'-V'|'--version')