Convert a libc backtrace to a source line number

Question

I have an MPI application with which combines both C and Fortran sources. Occasionally it crashes due to a memory related bug, but I am having trouble finding the bug (it is somewhere in someone else's code, which at the moment I'm not very familiar with). I haven't yet been able to catch it with gdb, but sometimes a glibc backtrace is output as shown below. The bug is probably close to "(main_main_+0x3bca)[0x804d5ce]", (but with a memory error, I know this may not be the case). My question is, does anyone know how to convert +0x3bca or 0x804d5ce into a particular line of the code? Any other suggestions on tracking down the bug would also be appreciated. I'm quite familiar with the basics of gdb. ``` *** glibc detected *** /home/.../src/finite_element: munmap_chunk(): invalid pointer: 0x09d83018 *** ======= Backtrace: ========= /lib/i386-linux-gnu/libc.so.6(+0x73e42)[0xb7409e42] /lib/i386-linux-gnu/libc.so.6(+0x74525)[0xb740a525] /home/.../src/finite_element(main_main_+0x3bca)[0x804d5…

Accepted Answer

If you are in `gdb` and you have debugging symbols, it is quite easy. Use `list`.

```
(gdb) list *0x804d5ce
```

This should give you the line of code, and show you the source if it is able to find the source file.

Without `gdb` you could try to use `addr2line`:

```
$ addr2line -e finite_element 0x804d5ce
```

Convert a libc backtrace to a source line number

Solution

Problem