[Crash-utility] Re: [RFC] Crash patch for DWARF CFI based unwind support

Hi Dave The following patch adds support for DWARF CFI based stack unwinding for crash. Since this method uses the call frame instructions for unwinding, it generates better backtraces than the existing backtrace mechanism. So when we have the unwind info available, this new method will be called, else we fall back to the existing mechanism. There still are a couple of things which need to be done, viz 1. Extend to obtaining unwind info from modules as well(currently doing only for the kernel) 2. Currently reading the unwind info from eh_frame section only(ie __start_unwind to __end_unwind). Need to add facility to read from the .debug_frame(if .debug_frame is present in cases where .eh_frame is absent. Will have to read from the vmlinux if we want to read the .debug_frame info) 3. Add FRAME_POINTER support. Please provide your suggestions and comments. Thanks Rachita