問題一：故障記錄時間2019年4月4日，查看系統日志報錯如下：
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]
解決方法：
根據系統日志報錯查詢得到關聯的包 rpm -q --whatprovides /lib64/libcairo.so.2
初步排查，根據系統日志報錯信息可知與當前系統中安裝的此rpm包有關
查詢相關材料進行核實確認,該rpm包版本較高，與當前系統環境不兼容
進行卸載操作
免依賴卸載 rpm -e cairo-1.15.12-3.el7.x86_64 --nodeps
下載舊版本的rpm包進行安裝
免依賴安裝 rpm -ivh cairo-1.14.8-2.el7.x86_64.rpm --nodeps
此時再次查詢系統日志已經不報該錯誤
問題二：故障記錄時間2019年2月28日,系統報錯日志如下
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
解決方法：1、重啟服務器並回退內核至上一個版本,刪除存在該問題的內核
查詢當前系統已安裝的內核版本
rpm -qa | grep kernel
查詢目前在使用的內核版本號
uname -sr
重啟服務器，在彈出顯示"內核版本"的啟動階段，手動切換內核版本號
刪除舊內核
yum remove kernel-3.10.0-693.el7.x86_64 #刪除舊內核 或者rpm -e kernel-3.10.0-693.el7.x86_64
2、查詢相關材料提供的解決方式如下：
centos7設置內核啟動順序
1、查看當前設備上安裝了幾個內核
cat /boot/grub2/grub.cfg |grep menuentry
2、查看當前內核
grub2-editenv list
3、修改默認啟動的內核
grub2-set-default 'CentOS Linux (3.10.0-862.9.1.el7.x86_64) 7 (Core)'