Mount CD/DVD caused reboot/hanged server.
 

Problem:
=======
Whenever I mount CD manually or automatically, the system either hanged or reboot by itself...depending on which server I am doing it on
I did a "grep -i" for error/fail/warning and there are no error in the /var/log/messages file for either one of them
...
The only different between the two servers is the memory: one has 8G and one has 4G.

Latest version of CentOS5. Updated with latest patch since yesterday.

============= Hardwares Info ===============

Dell T105 x86_64 Quad Core 1CPU - 8Gb RAM (server hanged) db01
Dell T105 x86_84 Duo Core 1CPU - 4Gb RAM (server rebooted) ap01

[root@ap01 ~]# uname -a
Linux ap01 2.6.18-92.1.22.el5 #1 SMP Tue Dec 16 11:57:43 EST 2008 x86_64 x86_64 x86_64 GNU/Linux


[root@ap01 mnt]# mkdir /mnt/cdrom
[root@ap01 mnt]# ls -la
total 20
drwxr-xr-x 3 root root 4096 Jan 14 08:44 .
drwxr-xr-x 27 root root 4096 Jan 14 08:26 ..
drwxr-xr-x 2 root root 4096 Jan 14 08:44 cdrom

[root@ap01 mnt]# mount -r /dev/cdrom /mnt/cdrom
mount: No medium found
[root@ap01 mnt]# eject
...
... put in the CentOS5 DVD
...
[root@ap01 mnt]# mount -r /dev/cdrom /mnt/cdrom
...
rebooted right away. I used the same CentOS 5 DVD I used for the install.
My Windows and Unbutu server can read this same DVD.

Both of the servers can also read it because they went into install mode as soon as it booted up.

[root@ap01 log]# eject -n
eject: device is `/dev/scd0'

[root@ap01 log]# dmesg|grep CD
Type: CD-ROM ANSI SCSI revision: 05
Uniform CD-ROM driver Revision: 3.20
sr 2:0:0:0: Attached scsi CD-ROM sr0


[root@ap01 ~]# cat /etc/fstab
/dev/VolGroup00/LogVol01 / ext3 defaults 1 1
LABEL=/boot /boot ext3 defaults 1 2
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
/dev/VolGroup00/LogVol00 swap swap defaults 0 0

[root@ap01 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol01
444G 13G 408G 4% /
/dev/sda1 99M 19M 76M 20% /boot
tmpfs 2.0G 0 2.0G 0% /dev/shm

[root@ap01 ~]# ls -la /dev |more
total 8
drwxr-xr-x 13 root root 3560 Jan 14 08:17 .
drwxr-xr-x 27 root root 4096 Jan 14 08:13 ..
drwxr-xr-x 3 root root 60 Jan 14 08:13 bus
lrwxrwxrwx 1 root root 4 Jan 14 08:13 cdrom -> scd0
lrwxrwxrwx 1 root root 4 Jan 14 08:13 cdrom-sr0 -> scd0
crw------- 1 root root 5, 1 Jan 14 08:13 console
lrwxrwxrwx 1 root root 11 Jan 14 08:13 core -> /proc/kcore
drwxr-xr-x 4 root root 80 Jan 14 08:13 cpu
drwxr-xr-x 6 root root 120 Jan 14 08:13 disk
lrwxrwxrwx 1 root root 13 Jan 14 08:13 fd -> /proc/self/fd
crw-rw-rw- 1 root root 1, 7 Jan 14 08:13 full
srwxrwxrwx 1 root root 0 Jan 14 08:17 gpmctl
...
brw------- 1 root root 253, 0 Jan 14 08:13 root
crw-r--r-- 1 root root 10, 135 Jan 14 08:13 rtc
brw-rw---- 1 root disk 11, 0 Jan 14 08:13 scd0
brw-r----- 1 root disk 8, 0 Jan 14 08:13 sda
brw-r----- 1 root disk 8, 1 Jan 14 08:13 sda1
brw-r----- 1 root disk 8, 2 Jan 14 08:13 sda2
brw-r----- 1 root disk 8, 16 Jan 14 08:13 sdb
brw-r----- 1 root disk 8, 17 Jan 14 08:13 sdb1
crw------- 1 root root 21, 0 Jan 14 08:13 sg0
crw------- 1 root root 21, 1 Jan 14 08:13 sg1
crw------- 1 root root 21, 2 Jan 14 08:13 sg2
drwxrwxrwt 2 root root 40 Jan 14 08:13 shm
crw------- 1 root root 10, 231 Jan 14 08:13 snapshot
lrwxrwxrwx 1 root root 15 Jan 14 08:13 stderr -> /proc/self/fd/2
lrwxrwxrwx 1 root root 15 Jan 14 08:13 stdin -> /proc/self/fd/0
lrwxrwxrwx 1 root root 15 Jan 14 08:13 stdout -> /proc/self/fd/1
crw------- 1 root root 4, 0 Jan 14 08:13 systty

Any help would be appreciated.

I moved the old messages files before I did the mount, and these are the first lines in the files after the reboot/hanged:

Jan 16 14:34:23 ap01 syslogd 1.4.1: restart.
Jan 16 14:34:23 ap01 kernel: klogd 1.4.1, log source = /proc/kmsg started.
Jan 16 14:34:23 ap01 kernel: Linux version 2.6.18-92.1.22.el5 (mockbuild@builder10.centos.org) (gcc version 4.1.2 20071124 (Red Hat 4.1.2-42)) #1 SMP Tue Dec 16 11:57:43 EST 2008

My first guess is weak PSU.

Sorry, I am new to this, and I am not sure of all the acronyms. PSU as in Power Supply Unit?

I am not familiar with PSU problems/symptoms, but I was able to install the whole OS by using the CD/DVD.
If it was a PSU problem would it have shown up earlier?

Also, I forgot to mention this before, but when I had a old RHEL5 installed on them, I was able to mount/umount CD/DVD without any problem. I had to remove them because the I don't have support to download the latest version of RH.

So this kind of suggest something with the latest version of CentOS5 and the hardware?

Moved: This thread has been moved at the OPs request

Solution
 

Looks like CentOS bug.

http://lkml.org/lkml/2008/1/10/163
https://bugzilla.redhat.com/show_bug.cgi?id=351451

The work around that worked for me is setting mem=4096M for the boot option in the /boot/grub/grub.conf as in

kernel /vmlinuz-2.6.18-92.1.22.el5 ro root=/dev/VolGroup00/LogVol01 mem=4096M rhgb quiet