Cannot bind ctrl-u to a readline function in bash.

[Woody Thrower]

It appears that bash cannot bind ctrl-u either by using the "bind" command,
or by reading .inputrc at startup.

This bind command does not work:
$ bind '"\C-u": history-search-backward'

This bind command does work:
$ bind '"\C-u": "foo"'

The following inputrc line does not work, even if the inputrc is explicitly
read via 'bind -f':
"\C-u": history-search-backward

Other lines in the same inputrc do work.

Interestingly, re-read-init-file (ctrl-x, ctrl-r by default) will
successfully bind Ctrl-U as defined in the inputrc.

Here's my bash version information:
$ bash --version
GNU bash, version 3.2.25(1)-release (x86_64-pc-linux-gnu)
Copyright (C) 2005 Free Software Foundation, Inc.