On 07.11.2024 12:30, Andrew Cooper wrote: > On 07/11/2024 9:48 am, Jan Beulich wrote: >> On 07.11.2024 10:40, Roger Pau Monné wrote: >>> On Thu, Nov 07, 2024 at 09:21:26AM +0000, Andrew Cooper wrote: >>>> On 07/11/2024 8:49 am, Roger Pau Monne wrote: >>>>> The tools infrastructure used to build livepatches for Xen >>>>> (livepatch-build-tools) consumes some DWARF debug information present in >>>>> xen-syms to generate a livepatch (see livepatch-build script usage of >>>>> readelf >>>>> -wi). >>>>> >>>>> The current Kconfig defaults however will enable LIVEPATCH without >>>>> DEBUG_INFO >>>>> on release builds, thus providing a default Kconfig selection that's not >>>>> suitable for livepatch-build-tools even when LIVEPATCH support is enabled, >>>>> because it's missing the DWARF debug section. >>>>> >>>>> Fix by forcing the selection of DEBUG_INFO from LIVEPATCH. >>>>> >>>>> Signed-off-by: Roger Pau Monné <[email protected]> >>>> Oops, yes. >>>> >>>> Reviewed-by: Andrew Cooper <[email protected]> >>>> >>>> Fixes tag ? >>> Was borderline on adding one, but wasn't sure since it's strictly >>> livepatch-build-tools that requires the DWARF data, but custom made >>> livepatches (like the examples in tests) do not require such >>> information. > > Ok. I guess it doesn't matter too much. > >> At which point: Is "select" really appropriate then? Wouldn't it be more >> logical then to change DEBUG_INFO's default to take LIVEPATCH into account >> (still permitting people to turn debug info off if they know they won't >> need it)? > > I am very disinterested in letting people who think they can do > livepatching without debug symbols shoot themselves in the foot like that. > > It's only debugging symbols. If people *really* think they know > better, they can strip them themselves.
Besides my abstract concern, let me also add a concrete practical one. I'm sure you've noticed that xen.efi is _much_ slower to link with debug info than without, or than xen-syms. That's a consequence of how GNU ld (really: libbfd) works internally. By not allowing DEBUG_INFO to stay off you're forcing me to either wait longer for every single one of my post-commit pre-push build tests, or to turn off LIVEPATCH there. The latter not really being a good idea. Nevertheless, as said in reply to Roger: Go ahead if you absolutely think that's the only sensible way. Jan
