新装了台fedora20的虚拟机，安装升级了一些东西后。启动时过了fedora的logo画面后就是黑屏。

也没提示不论什么错误，好在shell还能进去。查看/var/log/anaconda/syslog日志，发现错误例如以下：

20:40:34,794 NOTICE kernel:[ 1256.967907] type=1400 audit(1409517634.790:29): avc:  denied  { read write } for  pid=26214 comm="ldconfig" path="/dev/pts/0

     " dev="devpts" ino=3 scontext=system_u:system_r:ldconfig_t:s0 tcontext=system_u:object_r:devpts_t:s0 tclass=chr_file

1770 20:40:34,794 NOTICE kernel:[ 1256.970292] type=1400 audit(1409517634.792:30): avc:  denied  { read } for  pid=26214 comm="ldconfig" path="/proc/1025/mount

     s" dev="proc" ino=17433 scontext=system_u:system_r:ldconfig_t:s0 tcontext=system_u:system_r:initrc_t:s0 tclass=file

1771 20:41:02,416 NOTICE kernel:[ 1284.579392] type=1400 audit(1409517662.415:31): avc:  denied  { write } for  pid=30896 comm="ldconfig" path="/var/tmp/dracut

     -log.IKiLpk/systemd-cat" dev="sda5" ino=275146 scontext=system_u:system_r:ldconfig_t:s0 tcontext=system_u:object_r:initrc_tmp_t:s0 tclass=fifo_file

1772 20:41:02,419 NOTICE kernel:[ 1284.581518] type=1400 audit(1409517662.417:32): avc:  denied  { read } for  pid=30896 comm="ldconfig" name="ld.so.conf.d" de

     v="sda5" ino=276572 scontext=system_u:system_r:ldconfig_t:s0 tcontext=system_u:object_r:initrc_tmp_t:s0 tclass=dir

1773 20:41:02,424 NOTICE kernel:[ 1284.586709] type=1400 audit(1409517662.422:33): avc:  denied  { write } for  pid=30896 comm="ldconfig" name="etc" dev="sda5"

      ino=275151 scontext=system_u:system_r:ldconfig_t:s0 tcontext=system_u:object_r:initrc_tmp_t:s0 tclass=dir

1774 20:41:02,424 NOTICE kernel:[ 1284.586723] type=1400 audit(1409517662.422:34): avc:  denied  { add_name } for  pid=30896 comm="ldconfig" name="ld.so.cache~

     " scontext=system_u:system_r:ldconfig_t:s0 tcontext=system_u:object_r:initrc_tmp_t:s0 tclass=dir

1775 20:41:02,424 NOTICE kernel:[ 1284.586747] type=1400 audit(1409517662.422:35): avc:  denied  { create } for  pid=30896 comm="ldconfig" name="ld.so.cache~"

     scontext=system_u:system_r:ldconfig_t:s0 tcontext=system_u:object_r:initrc_tmp_t:s0 tclass=file

1776 20:41:02,424 NOTICE kernel:[ 1284.586853] type=1400 audit(1409517662.422:36): avc:  denied  { setattr } for  pid=30896 comm="ldconfig" name="ld.so.cache~"

      dev="sda5" ino=276580 scontext=system_u:system_r:ldconfig_t:s0 tcontext=system_u:object_r:initrc_tmp_t:s0 tclass=file

1777 20:41:02,424 NOTICE kernel:[ 1284.586879] type=1400 audit(1409517662.422:37): avc:  denied  { remove_name } for  pid=30896 comm="ldconfig" name="ld.so.cac

     he~" dev="sda5" ino=276580 scontext=system_u:system_r:ldconfig_t:s0 tcontext=system_u:object_r:initrc_tmp_t:s0 tclass=dir

1778 20:41:02,424 NOTICE kernel:[ 1284.586888] type=1400 audit(1409517662.422:38): avc:  denied  { rename } for  pid=30896 comm="ldconfig" name="ld.so.cache~"

     dev="sda5" ino=276580 scontext=system_u:system_r:ldconfig_t:s0 tcontext=system_u:object_r:initrc_tmp_t:s0 tclass=file

1779 20:41:20,086 NOTICE kernel:[ 1302.240139] type=1400 audit(1409517680.084:39): avc:  denied  { read write } for  pid=34152 comm="adduser" path="/dev/mapper

     /control" dev="devtmpfs" ino=8956 scontext=system_u:system_r:useradd_t:s0 tcontext=system_u:object_r:lvm_control_t:s0 tclass=chr_file

这说明一些操作被拒绝了。抽取第一条来看。avc: denied代表操作被拒绝。{ read write }代表该操作须要
读－read 和 写－write 许可。pid=26214
代表进程号为1876的进程试图运行操作……等等。

这些是SELINUX的安全检查，内核在运行系统调用前会询问 SELinux 进程是否获得了运行操作的授权。

解决的办法也非常easy，就是对对应的进程进行授权，或是关闭SELINUX，这里。我选择后者，改动文件/etc/selinux/config，将当中的

SELINUX=enforcing

改动为

SELINUX=disabled

重新启动后即可了。