Linux??core? ?????????????????????????????????

0.please set ulimit -c unlimited
# ulimit -c unlimited

1.please follow this page steps basically

1-1.edit the following line /etc/profile
# No core files by default
#ulimit -S -c 0 > /dev/null 2>&1
ulimit -c unlimited > /dev/null 2>&1

1-2.change /etc/sysconfig/init
add the following line in the end of init

1-3.change /etc/sysctl.conf
add the following:
# cat /etc/sysctl.conf
# Kernel sysctl configuration file for Red Hat Linux
# For binary values, 0 is disabled, 1 is enabled. See sysctl(8) and
# sysctl.conf(5) for more details.
fs.suid_dumpable = 1
kernel.core_pattern = /tmp/core
# Controls whether core dumps will append the PID to the core filename
# Useful for debugging multi-threaded applications
kernel.core_uses_pid = 1

Finally to make effective the change of sysctl.conf
# sysctl -p

after sysctl -p,
You may want to check the core file can be generated.
If you have a line "kernel.core_pattern = /tmp/core in sysctl.conf
the core file is generated under /tmp directory.

The users should try to generate a core file by sending "kill -11 PID"
after setting up the all above. I think this is important and if they can
not see the core file under expected place, they should ask core-dumpable steps
to the Redhat support.

Read More about [How to enable core dumps on RHEL5.4...