I found that unlocking a shadow user account will cause nscd to crash. I ran nscd with debug log turned on, it generated this trace when I did a usermod -U testuser: 20915: GETPWBYNAME (testuser) 20912: remove GETPWBYUID entry "0" 20912: remove GETPWBYUID entry "5177" 20912: remove GETPWBYUID entry "4257" 20912: remove GETPWBYNAME entry "???" 20912: remove GETPWBYNAME entry "???" 20912: remove GETPWBYNAME entry "???" 20912: remove GETPWBYUID entry "1324" 20912: remove GETPWBYNAME entry "???" 20912: remove GETPWBYNAME entry "???" 20912: remove GETPWBYNAME entry "???" 20912: remove GETPWBYUID entry "4499" 20912: remove GETPWBYUID entry "2581" 20912: remove GETPWBYUID entry "6221" 20912: remove GETPWBYNAME entry "???" 20912: remove GETPWBYNAME entry "???" 20912: remove GETPWBYUID entry "6411" 20912: remove GETGRBYGID entry "0" 20912: remove GETGRBYNAME entry "???" nscd has exited at this point.
can you please try to run nscd under gdb and see if you can get a backtrace? I can not reproduce this over here.
A bug was fioxed in the recent nscd that was causing nscd to abort when receiving an unknown request. The fixed glibc is in the devel tree now, will sow up on rawhide shortly