On Thu, Nov 07, 2024 at 10:48:21AM +0100, 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. > > 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)?
At least right now the only way to build useful livepatches for Xen (not dummy tests) is using livepatch-build-tools (that requires DWARF sections). My concern with using the Fixes tag was that I don't know whether initially the DWARF info was needed or not, or maybe whether people used a different tool rather than livepatch-build-tools. I don't mind changing, but I also don't think an hypervisor built with LIVEPATCH but without DEBUG_INFO is going to be useful to anyone given the requirements of the tools we provide to build livepatches. Thanks, Roger.
