Description of problem:
Testing https://bugzilla.novell.com/show_bug.cgi?id=798541

$ perl -e 'print "1","A"x50000000,"\r\n\r\n"' > /tmp/test.txt
$ join -i /tmp/test.txt /tmp/test.txt
Segmentation fault (core dumped)

$ rpm -q coreutils
coreutils-8.15-9.fc17.x86_64

Version-Release number of selected component:
coreutils-8.15-9.fc17

Additional info:
backtrace_rating: 4
cmdline:        join -i /tmp/test.txt /tmp/test.txt
crash_function: keycmp
executable:     /usr/bin/join
kernel:         3.7.3-101.fc17.x86_64
uid:            1000

Truncated backtrace:
Thread no. 1 (2 frames)
 #0 keycmp at join.c:527
 #1 system_join at join.c:913