Can not find core-dump file in Ubuntu 18.04 and Ubuntu 20.04 [closed]

I can't find any core dump files in ubuntu 18.04 and ubuntu 20.04, even I have changed core file size and /proc/sys/kernel/core_pattern:

smart@stable:~$ ulimit -c unlimitedsmart@stable:~$ ulimit -acore file size          (blocks, -c) unlimiteddata seg size           (kbytes, -d) unlimitedscheduling priority             (-e) 0file size               (blocks, -f) unlimitedpending signals                 (-i) 63699max locked memory       (kbytes, -l) 65536max memory size         (kbytes, -m) unlimitedopen files                      (-n) 1048576pipe size            (512 bytes, -p) 8POSIX message queues     (bytes, -q) 819200real-time priority              (-r) 0stack size              (kbytes, -s) 8192cpu time               (seconds, -t) unlimitedmax user processes              (-u) 1048576virtual memory          (kbytes, -v) unlimitedfile locks                      (-x) unlimitedsmart@stable:~$ cat /proc/sys/kernel/core_pattern |/usr/share/apport/apport %p %s %c %d %P %Esmart@stable:~$ sudo suroot@stable:~# echo "/var/crash/core-%e-%p-%t" > /proc/sys/kernel/core_pattern

After do that all, I run a program which will get a Segmentation fault error, but it didn't generate a core-dump file in /var/crash/, so what wrong with that?