In gdb-4.18-6, I am seeing problems when loading shared library symbols, from certain libraries especially. This is when using the "sharedlibrary" command from inside gdb. gdb just hangs while reading the symbols. gdb-4.18-4 does NOT seem to have this problem. It may or may not be related to the fact that I just switched CPU's in my machine, from a Pentium/MMX 233 to an AMD K6-2/400. I had been successfully using 4.18-6 on this program (mozilla) prior to changing the CPU, but I've also updated the code since then, so either one could be to blame.
Not a lot to be done without a test case. Feel to submit one, either here in bugzilla (as an attachment) or directly to the GDB maintainers at http://sourceware.cygnus.com/gdb/