Re: [PATCH stable 5.15 0/2] kbuild: Fix compilation for latest pahole release

From: Greg KH <gregkh@linuxfoundation.org>
To: Jiri Olsa <olsajiri@gmail.com>
Cc: Nathan Chancellor <nathan@kernel.org>,
	stable@vger.kernel.org, bpf@vger.kernel.org,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Martin Rodriguez Reboredo <yakoyoku@gmail.com>,
	Andrii Nakryiko <andrii@kernel.org>
Subject: Re: [PATCH stable 5.15 0/2] kbuild: Fix compilation for latest pahole release
Date: Tue, 18 Oct 2022 08:45:25 +0200	[thread overview]
Message-ID: <Y05LhQzMnJSpK0UT@kroah.com> (raw)
In-Reply-To: <Y03Iq2GiS7XfhOxL@krava>

On Mon, Oct 17, 2022 at 11:27:07PM +0200, Jiri Olsa wrote:
> On Mon, Oct 17, 2022 at 11:02:39AM -0700, Nathan Chancellor wrote:
> > On Mon, Sep 19, 2022 at 12:14:40AM +0200, Jiri Olsa wrote:
> > > On Tue, Sep 06, 2022 at 02:03:30PM +0200, Greg KH wrote:
> > > > On Mon, Sep 05, 2022 at 09:04:10AM +0200, Jiri Olsa wrote:
> > > > > On Sun, Sep 04, 2022 at 04:10:09PM +0200, Greg KH wrote:
> > > > > > On Sun, Sep 04, 2022 at 03:18:59PM +0200, Jiri Olsa wrote:
> > > > > > > hi,
> > > > > > > new version of pahole (1.24) is causing compilation fail for 5.15
> > > > > > > stable kernel, discussed in here [1][2]. Sending fix for that plus
> > > > > > > one dependency patch.
> > > > > > > 
> > > > > > > Note for patch 1:
> > > > > > > there was one extra line change in scripts/pahole-flags.sh file in
> > > > > > > its linux tree merge commit:
> > > > > > > 
> > > > > > >   fc02cb2b37fe Merge tag 'net-next-for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
> > > > > > > 
> > > > > > > not sure how/if to track that, I squashed the change in.
> > > > > > 
> > > > > > Squashing is fine, thanks.
> > > > > > 
> > > > > > And do we also need this for kernels older than 5.15?  Like 5.10 and 5.4?
> > > > > 
> > > > > yes, 5.10 needs similar patchset, but this for 5.15 won't apply there,
> > > > > so I'll send it separately
> > > > > 
> > > > > 5.4 passes compilation, but I don't think it will boot properly, still
> > > > > need to check on that
> > > > > 
> > > > > in any case, more patches are coming ;-)
> > > > 
> > > > Ok, these two are now queued up, feel free to send the rest when you
> > > > have them ready.
> > > 
> > > hi,
> > > as for 5.10 changes, I have them ready, pushed in here:
> > >   git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git pahole_fix_5_10
> > > 
> > > but it looks like CONFIG_DEBUG_INFO_BTF is not being used in 5.10,
> > > because I had to backport other similar option, that would break
> > > the build even earlier (--skip_encoding_btf_vars), or people use
> > > just old pahole ;-)
> > > 
> > > I suggest we wait with this change until somebody actually wants
> > > this fixed, AFAICS there's no report of broken 5.10 build yet
> > 
> > Consider this your first report :)
> 
> va bene ;-)
> 
> > 
> > My build containers include the latest pahole, as I have noticed more
> > issues with older pahole in newer kernels than newer pahole in older
> > kernels, as least until now. I have tripped over this issue on both 5.19
> > and 5.10, as the stable-only commit b775fbf532dc ("kbuild: Add
> > skip_encoding_btf_enum64 option to pahole") was only applied to 5.15,
> > even though it is needed in all kernels prior to 6.0.
> > 
> > Please consider explicitly sending the 5.10 series to stable and
> 
> sure I'll rebase and post it
> 
> > requesting b775fbf532dc to be applied to 5.19.
> 
> hm, it was already posted for 5.19:
> https://lore.kernel.org/bpf/20220916171234.841556-1-yakoyoku@gmail.com/
> 
> Greg,
> is there something missing for it to be taken?

Ick, sorry, this got lost.  Now queued up.

greg k-h