问题一：故障记录时间2019年4月4日，查看系统日志报错如下：
tail -f /var/log/messages Apr 4 16:29:16 localhost kernel: tracker-extract[18065]: segfault at 205f0 ip 00000000000205f0 sp 00007ffdef1af718 error 14 in tracker-extract[400000+15000] Apr 4 16:29:16 localhost abrt-hook-ccpp: Process 18065 (tracker-extract) of user 1005 killed by SIGSEGV - dumping core Apr 4 16:29:16 localhost journal: Could not load module '/usr/lib64/tracker-1.0/extract-modules/libextract-pdf.so': /usr/lib64/libcairo.so.2: undefined symbol: FT_Get_Var_Design_Coordinates Apr 4 16:29:16 localhost abrt-hook-ccpp: Failed to create core_backtrace: dwfl_getthread_frames failed: No DWARF information found Apr 4 16:29:16 localhost abrt-hook-ccpp: Process 18118 (tracker-extract) of user 1005 killed by SIGSEGV - ignoring (repeated crash) Apr 4 16:29:16 localhost abrtd: Size of '/var/spool/abrt' >= 1000 MB (MaxCrashReportsSize), deleting new directory 'ccpp-2019-04-04-16:29:16-18065' Apr 4 16:29:17 localhost journal: Could not load module '/usr/lib64/tracker-1.0/extract-modules/libextract-pdf.so': /usr/lib64/libcairo.so.2: undefined symbol: FT_Get_Var_Design_Coordinates Apr 4 16:29:17 localhost kernel: show_signal_msg: 1 callbacks suppressed Apr 4 16:29:17 localhost kernel: tracker-extract[18297]: segfault at 205f0 ip 00000000000205f0 sp 00007ffe797a6fd8 error 14 in tracker-extract[400000+15000] Apr 4 16:29:17 localhost abrt-hook-ccpp: Process 18297 (tracker-extract) of user 1005 killed by SIGSEGV - ignoring (repeated crash) Apr 4 16:29:18 localhost journal: Could not load module '/usr/lib64/tracker-1.0/extract-modules/libextract-pdf.so': /usr/lib64/libcairo.so.2: undefined symbol: FT_Get_Var_Design_Coordinates Apr 4 16:29:18 localhost kernel: tracker-extract[18366]: segfault at 205f0 ip 00000000000205f0 sp 00007ffc99e55ca8 error 14 in tracker-extract[400000+15000] Apr 4 16:29:18 localhost abrt-hook-ccpp: Process 18366 (tracker-extract) of user 1005 killed by SIGSEGV - ignoring (repeated crash) Apr 4 16:29:18 localhost journal: Could not load module '/usr/lib64/tracker-1.0/extract-modules/libextract-pdf.so': /usr/lib64/libcairo.so.2: undefined symbol: FT_Get_Var_Design_Coordinates Apr 4 16:29:18 localhost kernel: tracker-extract[18454]: segfault at 205f0 ip 00000000000205f0 sp 00007ffd38485ce8 error 14 in tracker-extract[400000+15000] Apr 4 16:29:18 localhost abrt-hook-ccpp: Process 18454 (tracker-extract) of user 1005 killed by SIGSEGV - ignoring (repeated crash) Apr 4 16:29:19 localhost journal: Could not load module '/usr/lib64/tracker-1.0/extract-modules/libextract-pdf.so': /usr/lib64/libcairo.so.2: undefined symbol: FT_Get_Var_Design_Coordinates Apr 4 16:29:19 localhost kernel: tracker-extract[18528]: segfault at 205f0 ip 00000000000205f0 sp 00007ffeb7c15978 error 14 in tracker-extract[400000+15000] Apr 4 16:29:19 localhost abrt-hook-ccpp: Process 18528 (tracker-extract) of user 1005 killed by SIGSEGV - ignoring (repeated crash) Apr 4 16:29:19 localhost journal: Could not load module '/usr/lib64/tracker-1.0/extract-modules/libextract-pdf.so': /usr/lib64/libcairo.so.2: undefined symbol: FT_Get_Var_Design_Coordinates Apr 4 16:29:19 localhost kernel: tracker-extract[18583]: segfault at 205f0 ip 00000000000205f0 sp 00007ffc23a5c168 error 14 in tracker-extract[400000+15000]
解决方法：
根据系统日志报错查询得到关联的包 rpm -q --whatprovides /lib64/libcairo.so.2
初步排查，根据系统日志报错信息可知与当前系统中安装的此rpm包有关
查询相关材料进行核实确认,该rpm包版本较高，与当前系统环境不兼容
进行卸载操作
免依赖卸载 rpm -e cairo-1.15.12-3.el7.x86_64 --nodeps
下载旧版本的rpm包进行安装
免依赖安装 rpm -ivh cairo-1.14.8-2.el7.x86_64.rpm --nodeps
此时再次查询系统日志已经不报该错误
问题二：故障记录时间2019年2月28日,系统报错日志如下
Feb 28 14:12:26 localhost systemd-logind: Failed to start session scope session-561903.scope: Failed to activate service 'org.freedesktop.systemd1': timed out
解决方法：1、重启服务器并回退内核至上一个版本,删除存在该问题的内核
查询当前系统已安装的内核版本
rpm -qa | grep kernel
查询目前在使用的内核版本号
uname -sr
重启服务器，在弹出显示"内核版本"的启动阶段，手动切换内核版本号
删除旧内核
yum remove kernel-3.10.0-693.el7.x86_64 #删除旧内核 或者rpm -e kernel-3.10.0-693.el7.x86_64
2、查询相关材料提供的解决方式如下：
centos7设置内核启动顺序
1、查看当前设备上安装了几个内核
cat /boot/grub2/grub.cfg |grep menuentry
2、查看当前内核
grub2-editenv list
3、修改默认启动的内核
grub2-set-default 'CentOS Linux (3.10.0-862.9.1.el7.x86_64) 7 (Core)'