On Fri, Jul 22, 2016 at 06:49:01AM +0900, Byungchul Park wrote: > On Thu, Jul 21, 2016 at 04:21:52PM -0500, Josh Poimboeuf wrote: > > Convert show_trace_log_lvl() to the new unwinder. dump_trace() has been > > deprecated. > > > > show_trace_log_lvl() is special compared to other users of the unwinder. > > It's the only place where both reliable *and* unreliable addresses are > > needed. With frame pointers enabled, most stack walking code doesn't > > want to know about unreliable addresses. But in this case, when we're > > dumping the stack to the console because something presumably went > > wrong, the unreliable addresses are useful: > > > > - They show stale data on the stack which can provide useful clues. > > > > - If something goes wrong with the unwinder, or if frame pointers are > > corrupt or missing, all the stack addresses still get shown. > > > > So in order to show all addresses on the stack, and at the same time > > figure out which addresses are reliable, we have to do the scanning and > > the unwinding in parallel. > > > > The scanning is done with the help of get_stack_info() to traverse the > > stacks. The unwinding is done separately by the new unwinder. > > > > In theory we could simplify show_trace_log_lvl() by instead pushing some > > of this logic into the unwind code. But then we would need some kind of > > "fake" frame logic in the unwinder which would add a lot of complexity > > and wouldn't be worth it in order to support only one user. > > > > Another benefit of this approach is that once we have a DWARF unwinder, > > we should be able to just plug it in with minimal impact to this code. > > > > Another change here is that callers of show_trace_log_lvl() don't need > > to provide the 'bp' argument. The unwinder already finds the relevant > > frame pointer by unwinding until it reaches the first frame after the > > provided stack pointer. > > Hello, > > You seem to have changed a lot of code with which I dealt in another patch. > I might be supposed to wait until yours will be done. I need to check yours > at first anyway.
Yeah, that's why I added you to cc :-) I think this obsoletes your patches. -- Josh
