服务器报这个错误：

kernel panic - not symcing: lib/dec_and_lock.c:32:spin_lock(kernel/user.c:c034e5c0)already locked by lib/dec_and_lock.c/32

操作步骤：

1,vi /etc/selinux/config

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
# enforcing - SELinux security policy is enforced.
# permissive - SELinux prints warnings instead of enforcing.
# disabled - SELinux is fully disabled.
SELINUX=disabled
# SELINUXTYPE= type of policy in use. Possible values are:
# targeted - Only targeted network daemons are protected.
# strict - Full SELinux protection.
SELINUXTYPE=targeted

把SELINUX设置为disabled

2,升级内核

备份boot目录，cp -R /boot /boot.old

安装新内核

rpm -ivh kernel-2.6.9-42.EL.i686.rpm

提示出错：
warning: kernel-2.6.9-42.EL.i686.rpm: V3 DSA signature: NOKEY, key ID db42a60e
error: Failed dependencies:
mkinitrd >= 4.2.1.6-1 is needed by kernel-2.6.9-42.EL.i686

uname -a查看版本信息
Linux tonykorn97 2.6.9-5.EL #1 Wed Jan 5 19:22:18 EST 2005 i686 i686 i386 GNU/Linux

mkinitrd版本太低

mkinitrd --version
mkinitrd: version 4.1.18

删除mkinitrd

rpm -e --nodeps mkinitrd-4.1.18-2

重新安装mkinitrd和内核

[root@tonykorn97 /]# rpm -ivh mkinitrd-4.2.1.6-1.i386.rpm
warning: mkinitrd-4.2.1.6-1.i386.rpm: V3 DSA signature: NOKEY, key ID db42a60e
Preparing... ########################################### [100%]
1:mkinitrd ########################################### [100%]
[root@tonykorn97 /]# rpm -ivh kernel-2.6.9-42.EL.i686.rpm
warning: kernel-2.6.9-42.EL.i686.rpm: V3 DSA signature: NOKEY, key ID db42a60e
Preparing... ########################################### [100%]
1:kernel ########################################### [100%]

查看以后是否出错，看是否是这两方面的原因。