Bash uses 100% CPU time (when started by "su")

[Thomas Loeber]

Configuration Information:
Machine: i686
OS: linux-gnu
Compiler: i686-pc-linux-gnu-gcc
Compilation CFLAGS: -DPROGRAM='bash' -DCONF_HOSTTYPE='i686' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i686-pc-linux-gnu' 
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL 
-DHAVE_CONFIG_H -I. -I. -I./include -I./lib -march=athlon-xp -O2 
-fomit-frame-pointer -pipe
uname output: Linux schlumpfine 2.6.19-gentoo-r5 #3 PREEMPT Sun Feb 11 11:26:54 
CET 2007 i686 AMD Athlon(tm) XP 2600+ AuthenticAMD GNU/Linux
Machine Type: i686-pc-linux-gnu

Bash Version: 3.1
Patch Level: 17
Release Status: release

Description:
When using bash and then starting a second bash by using "su", the bash
started by "su" will use 100% CPU time if it is in reverse-i-search
mode and the first bash process is killed with SIGHUP (using "kill" or
e. g. by closing the xterm window).

This also happens with Bash 3.2_p9 and Readline 5.2_p1.
I'm using su from shadow version 4.0.18.1.

Repeat-By:
1) log in to a console or open an xterm/konsole/...
2) echo $$ (keep this in mind as PID#1)
3) su $USER
4) echo $$ (keep this in mind as PID#2)
5) Hit Ctrl+R (bash is in reverse-i-search mode now)
6) On a different console type: kill -HUP <PID#1>
7) The bash with PID#2 now runs endlessly with 100% CPU usage
8) kill -9 <PID#2>