Subject: Re: [PATCHv6 bpf] bpf: Move iterator functions into special init section

From: Arnaldo Carvalho de Melo <[email-masked]>
Date: Wed, 11 Nov 2020 09:38:20 -0300

Em Wed, Nov 11, 2020 at 09:37:38AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Wed, Nov 11, 2020 at 12:26:29PM +0100, Daniel Borkmann escreveu:
> > On 11/10/20 4:40 PM, Jiri Olsa wrote:
> > > With upcoming changes to pahole, that change the way how and
> > > which kernel functions are stored in BTF data, we need a way
> > > to recognize iterator functions.
> > > 
> > > Iterator functions need to be in BTF data, but have no real
> > > body and are currently placed in .init.text section, so they
> > > are freed after kernel init and are filtered out of BTF data
> > > because of that.
> > > 
> > > The solution is to place these functions under new section:
> > >    .init.bpf.preserve_type
> > > 
> > > And add 2 new symbols to mark that area:
> > >    __init_bpf_preserve_type_begin
> > >    __init_bpf_preserve_type_end
> > > 
> > > The code in pahole responsible for picking up the functions will
> > > be able to recognize functions from this section and add them to
> > > the BTF data and filter out all other .init.text functions.
> > > 
> > > Cc: Arnaldo Carvalho de Melo <[email-masked]>
> > > Suggested-by: Yonghong Song <[email-masked]>
> > > Signed-off-by: Jiri Olsa <[email-masked]>
> > 
> > LGTM, applied, thanks! Also added a reference to the pahole commit
> 
> Applied to what branch? I'm trying to test it now :-)

Nevermind, bpf/master, I was looking at bpf-next/master.

- Arnaldo