Why can't I see the information for all the frames in a core file in gdb, pstack, etc?

Issue

• When I try to debug a crash in gdb I can not see the information for some of the frames, for example;

(gdb) bt
#0  0x0000000000000000 in ?? ()
#1  0x000000000042fd69 in ?? ()
#2  0x0000c757dac65add in ?? ()
#3  0x00007fdb8402b440 in ?? ()
#4  0x0000000052325589 in ?? ()
#5  0x0000000052325589 in ?? ()
#6  0x0000000000000000 in ?? ()