Just updated from glibc 2.2-12 (Errata RPM) to 2.2.4-18.7.0 (Newest Errata RPM). Some programs now coredump, like the last nmap (2.54b30), even if recompiled under this new glibc. Returned under old Errata RPM, recompiled nmap, it no longer coredumps.
Just in case: IPV6 kernel module is loaded.
You should never use IPv6 in 2.2 kernels. Either upgrade to 2.4 kernel, or no IPv6. IPv6 is broken a lot in 2.2. Or was this under 2.4 kernel?
If I understand you, RedHat has done a mistake by including IPv6 tools in RedHat 7.0 with Kernel 2.2.x (traceroute6, ping6)... Anyway, it is a 2.2.19 kernel; but nmap doesn't know about ipv6. So, are you sure that without ipv6 module loaded, nmap won't coredump with these glibc ? Because this is a busy computer, and I would like to avoid rebooting if unnecessary... It doesn't use ipv6 actually, the module is loaded but cannot be unloaded without rebooting.
... tested on another RH 7.0 WITHOUT ipv6: exactly the same thing. Binary compiled and ran under new glibc: coredump. Binary compiled and ran under previous glibc: ok.
This bug is against a very old glibc version. I doubt there is any point keeping it open. Support for this code is long gone and all new releases,e specially RHL9, should have no such problem.