Written in c a postgres plug-in, file form is so, in the process of running, sometimes will collapse, so capture the coredump file when the collapse, but in the use GDB stack, the bt command analysis found that the function names are question marks, result in unable to pinpoint the location of the crash, when compile the plug-in, has added the -g option, and use the file command to import the symbols so file, but the stack information or question mark, check a lot of information on the Internet, can't solve this problem, could you tell me how to through the coredump file see collapse the stack information accurately, rather than a question mark? Thank you very much!