On May 8, 2017 7:40:49 AM PDT, Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote: >On Sun, May 07, 2017 at 10:35:28PM -0700, Andy Lutomirski wrote: >> I think that, if the code were sufficiently robust, it would be handy >> if the unwinder displayed function arguments. DWARF can do that to a >> limited extent. > >Honestly I get the feeling that displaying function arguments wouldn't >be realistic (DWARF or no DWARF). On x86-64, arguments are passed in >registers, so tracking down their values is a lot more involved than >just looking at the stack. > >The DWARF CFI only shows you the callee-saved registers. To figure out >the other registers you'd have to dive into the other DWARF sections >and >examine previous stack frames for clues. I think it's not a >deterministic process, based on how often I see gdb complain with >'<value optimized out>'. I'd bet it's a lot harder than a basic stack >dump. > >Also, most kernel functions rely on pointer arguments, which are pretty >much useless without dumping the contents of the structs they point to. >But then doing that properly would be a whole new level of difficulty. At some point you are just reinventing k(g)db... -- Sent from my Android device with K-9 Mail. Please excuse my brevity. -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
