On Tue, Nov 07, 2017 at 04:25:10PM -0500, Mikulas Patocka wrote: > > The technical reason for avoiding the guess unwinder is that it's > > sketchy: it gives false positive results. > > I've always used kernels without frame pointer and I don't see any problem > with decoding stack traces with some phantom entries that were left in the > stack - it's easy to find out which functions could call which functions > and discard the phantom entries. > > > Not only for oopses, but for all the other users of the unwinder: > > /proc/<pid>/stack, perf, lockdep, etc. So it's a correctness issue. > > Experts need these features, but casual users don't. > > > I agree with you that the frame pointer unwinder has drawbacks, but if > > somebody cares about those drawbacks, I would consider that person an > > "expert" ;-) > > The Kconfig entry says that frame pointers degrade performance by 5-10% - > so almost any user would care about it, not just experts. You're running a 32bit kernel.... isn't that the same as not caring about performance in any case? I suppose the solution you're looking for is making ORC work for it; but given hardly anybody still cares about 32bit x86 you'll probably have to do it yourself. -- 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
