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Created attachment 525570 [details]
strace of the script on 64bit

Description of problem:

On RHEL 6.1 64bit the following ksh never comes back:

#!/bin/ksh
f_cmd () {
	CMD="$1"
	OUT="$(eval "$CMD" 2>&1)"
	echo "$OUT"
}
f_cmd "dd if=/dev/zero bs=128001 count=1 | cat | cat >/dev/null"

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

ksh-20100621-6.el6.x86_64

How reproducible:

always

Steps to Reproduce:
1. run the script from above on a 64bit RHEL 6.1 machine
  
Actual results:

The script never exits

Expected results:

Script should exit after executing the commands

Additional info:

The problem only occurs on 64bit architecture, not on 32bit. Also, current fedora 64bit does not show the problem.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHBA-2011-1647.html