How to debug crash, when backtrace starts with zero

my long running application crashes randomly with segmentation fault. When trying to debug the generated coredump, I get stuck with wierd stacktrace:

(gdb) bt full
#0 __memmove_ssse3 () at ../sysdeps/i386/i686/multiarch/memcpy-ssse3.S:2582
No locals.
#1 0x00000000 in ?? ()
No symbol table info available.

How it can happen, that the backtrace starts at 0x00000000?
What can I do to debug this issue more? I can't run it in gdb as it may take even a week till the crash occures.

Generally this means that the return address on the stack has been overwritten with 0, probably due to overrunning the end of an on-stack array. You can trying building with address sanitizer on gcc or clang (if you are using them). Or you can try running with valgrind to see if it will tell you about invalid memory writes.