Getting backtrace of a process

I am trying to get create a custom error log of a process when it causes a segmentation fault. We can modify the* /proc/sys/kernel/core_pattern* file to pipe the core information to a handler binary. I am trying to use the *libunwind *library within this handler to also get the backtrace information but it is failing. As per my understanding, the *do_coredump* kills the faulty process inside *coredump_wait* function before invoking the userspace handler, This might be the reason the libunwind fails to gather the backtrace as it uses PTRACE calls. Is there any way to overcome this without modifying the kernel code?