Hi Arnaldo and Masami, On Fri, Nov 20, 2015 at 09:10:44AM -0300, Arnaldo Carvalho de Melo wrote: > Em Fri, Nov 20, 2015 at 09:05:23AM +0000, 平松雅巳 / HIRAMATU，MASAMI escreveu: > > >From: Namhyung Kim [mailto:[email protected]] > > > > > >Backtrace is a crucial info for debugging. And upcoming refcnt > > >tracking facility also wants to use it. > > > > > >So instead of relying on glibc's backtrace_symbols[_fd] which misses > > >some (static) functions , use our own symbol searching mechanism. To > > >do that, add perf_thread global variable to keep its maps and symbols. > > > > Hmm, I doubt that this can work for debugging situation, because > > sometimes backtrace facilities has to debug itself by itself. > > That is a valid point, possibly we can have both and when we think that > the code we rely on for resolving symbols has issues, activate the > other, more expensive, binutils/elfutils spawned command line utilities > to do compare the results?
Yeah, that's a possible solution. We can start by using our own, and if there's a certain amount of failure in symbol resolving, then fallback to glibc's backtrace_symbols + addr2line. > > > For the some (static) functions, I'd rather like to use glibc's > > backtrace_symbols and addr2line or even with raw address for > > reliability... I also printed the raw addresses in case of doubts, so you could verify its correctness. :) And IMHO, if something is severely broken, we might not rely on glibc too. Having said that, I agree with your concern and it needs the fallback method for possible malfunction. But I guess it'd work quite well for most cases so it's worth trying to convert using it. I'll work on the fallback method then.. Thanks, Namhyung -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
