On Thu, Mar 31, 2016 at 03:03:16PM +0200, Miroslav Benes wrote: > On Fri, 25 Mar 2016, Josh Poimboeuf wrote: > > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > > index 2dc18605..76274b8 100644 > > --- a/arch/x86/Kconfig > > +++ b/arch/x86/Kconfig > > @@ -138,6 +138,7 @@ config X86 > > select HAVE_PERF_REGS > > select HAVE_PERF_USER_STACK_DUMP > > select HAVE_REGS_AND_STACK_ACCESS_API > > + select HAVE_RELIABLE_STACKTRACE if X86_64 && FRAME_POINTER > > I understand we have to rely on frame pointer for now. Do you plan to > switch to dwarf unwinder one day in the future? IOW is there a plan to > implement dwarf stuff generation in objtool and then to have a dwarf-based > stack unwinder upstream and to use it for live patching?
Yes, adding DWARF validation and generation to objtool and creating a DWARF unwinder upstream are all planned, hopefully soon. > We have FRAME_POINTER unset in SLES for performance reasons (there was > some 5 percent slowdown measured in the past. However we should redo the > experiments.) and one day we'd really like to switch to upstream from > kgraft :). So I'm just asking. If you redo the experiments and have some useful data to share, please do share :-) -- Josh
