On Sun, Nov 22, 2020 at 2:56 PM Jiri Olsa <jolsa@xxxxxxxxxx> wrote: > > On Fri, Nov 20, 2020 at 05:13:24PM -0800, Andrii Nakryiko wrote: > > On Sat, Nov 14, 2020 at 2:39 PM Jiri Olsa <jolsa@xxxxxxxxxx> wrote: > > > > > > hi, > > > recent btf encoder's changes brakes BTF data for some gcc > > > versions. The problem is that some functions can appear > > > in dwarf data in some instances without arguments, while > > > they are defined with some. > > > > Hey Jiri, > > > > So this approach with __start_mcount_loc/__stop_mcount_loc works for > > vmlinux only, but it doesn't work for kernel modules. For kernel > > modules there is a dedicated "__mcount_loc" section, but no > > __start/__stop symbols. I'm working around for now by making sure > > functions that I need are global, but it would be nice to have this > > working for modules out of the box as well. > > hi, > I checked and it's bit more tricky than with vmlinux, > addresses are in __mcount_loc, but it's all zeros and > it gets filled after via relocation from .rela__mcount_loc > > I think we could do relocation of __mcount_loc section > with zero base and get all base addresses.. and then > continue from there with current code checks > > I'll check on it tomorrow Thanks! > > > > > If you get a chance to fix this soon, that would be great. If not, > > I'll try to get to this ASAP as well, because it would be nice to have > > this in the same version of pahole that got static function BTFs for > > vmlinux (if Arnaldo doesn't mind, of course). > > we're eagerly expecting the new pahole with the DWARF bug > workaround, so we asked Arnaldo to release soon, how big > problem is it for you if the modules fix is in the next one? > Not a problem, I just hate remembering all the versions of all the binaries/libraries/compilers and what each version added. 1.19 had a chance to be the version which makes fentry/fexit work for all cases, but I guess it won't happen :) No big deal. > thanks, > jirka > > > > > > > > > v3 changes: > > > - move 'generated' flag set out of should_generate_function > > > - rename should_generate_function to find_function > > > - added ack > > > > > > v2 changes: > > > - drop patch 3 logic and just change conditions > > > based on Andrii's suggestion > > > - drop patch 2 > > > - add ack for patch 1 > > > > > > thanks, > > > jirka > > > > > > > > > --- > > > Jiri Olsa (2): > > > btf_encoder: Generate also .init functions > > > btf_encoder: Fix function generation > > > > > > btf_encoder.c | 86 +++++++++++++++++++++----------------------------------------------------------------- > > > 1 file changed, 21 insertions(+), 65 deletions(-) > > > > > >
