(gdb) run
Missing separate debuginfos, use: debuginfo-install glibc-2.17-222.el7.x86_64
# vim /etc/yum.repos.d/CentOS-Debuginfo.repo
enable=1
# yum install glibc
# debuginfo-install glibc-2.17-222.el7.x86_64
# gdb -c core a.out
