Description of problem:

On trying to install Fedora Core 6 Test 3 over a pre-existing Gentoo 
distribution (with a JFS data partition), at the stage where Fedora Core 
attempts to detect previous Linux installations, the screen will revert to 
text (if in a graphical install) and display several lines of random 
characters, followed by a line stating that ginstall has segfaulted.

The same problem occurs when using the Fedora Core 6 Test 3 boot CD in rescue 
mode, at the same point, with the same error, if I tell it to detect an 
existing Linux partition. A rough guess, based on the status bar, is that the 
detect routine crashes specifically when it hits the root partition.

Other information that may be useful:

The version of Gentoo is the most recent
The disk layout is boot partition (ext3), swap space, root partition (ext3) 
and data partition (jfs)
There are no free partition slots and there is no free disk space
The machine is a Dell Dimension with a Pentium IV and has a motherboard with 
the Intel i810 graphics chip built in

Version-Release number of selected component (if applicable):

Fedora Core 6 Test 3 boot CD.

How reproducible:

It occurs every time I attempt to use FC6t3 to either conduct a rescue (with 
detect)

Steps to Reproduce:
-2. Install the current version of Gentoo, creating four partitions, 
designating the first as /boot, the second as swap, the third as / and the 
fourth as unused. Swap is 2.5xRAM. The sum of the four partitions should 
occupy 100% of the disk.
-1. Format the fourth partition as JFS.

1. Boot from the Fedora Core 6 test 3 CD.
2. Either select install, or select rescue then select detect existing 
partitions.
  
Actual results:
The installer will print garbage and segfault. A soft reboot will not work.


Expected results:
The Linux detector should probably ignore any alien OS or alien distribution 
where the relevant configuration files differ from Red Hat/Fedora Core.

Additional info:
Fedora Core 6 test 1 installed successfully on the same machine with no 
errors.
Fedora Core 6 test 2 failed to handle the i810 graphics card (this bug has 
been fixed in test 3)
Fedora Core 6 test 2 installed successfully on a Dell Dimension which uses a 
Radeon graphics card and does not have the Intel i810 (so it is not exactly 
the same motherboard), but is otherwise identical to the machine on which a 
problem has been demonstrated, including having an alien Linux distribution 
previously installed.