RPM sometimes hangs during package upgrade (rpm -Uvh ...) rpm can not be killed by ctl-C. Only by kill -9 Then , after rpm is killed, rpm does not work right. I need to reboot the computer to get it working. Second time the same rpm -Uvh ... command work OK. I have this with RedHat 8.0. No such problem with RedHat 7.2 or 7.3. People say (I did not verify this myselft) that such rpm hangs also occure in RedHat 9.
Yes, there's a SIGCHLD missed in rpm-4.1-1.06. FIxed in rpm-4.1.1, currently available at ftp://ftp.rpm.org/pub/rpm/test-4.1.1