Re: [OE-core] [PATCH 2/4] lttng-modules: update to 2.13.0

["Andrey Zhizhikin" <andrey.z@gmail.com>]

Hello Bruce,

On Fri, Aug 20, 2021 at 3:21 PM Andrey Zhizhikin <andrey.z@gmail.com> wrote:
>
> On Fri, Aug 20, 2021 at 2:57 PM Bruce Ashfield <bruce.ashfield@gmail.com> wrote:
> >
> > On Fri, Aug 20, 2021 at 7:13 AM Andrey Zhizhikin <andrey.z@gmail.com> wrote:
> > >
> > > Hello Bruce,
> > >
> > > On Tue, Aug 17, 2021 at 5:27 PM Bruce Ashfield <bruce.ashfield@gmail.com> wrote:
> > > >
> > > > From: Bruce Ashfield <bruce.ashfield@gmail.com>
> > > >
> > > > Updating to 2.13.0, so we can pick up the latest -stable and
> > > > support for 5.14+ kernels.
> > > >
> > > > We refresh one patch for new context, and update the LICENSE
> > > > checksum due to commit 2df37e95fa4303 [Cleanup: Move headers from
> > > > toplevel to include/lttng/]. which impacted the LICENSE file (but
> > > > licensing is the same).
> > >
> > > I'm seeing a build failure with this new LTTng and CONFIG_TRACEPOINTS
> > > not enabled on the kernel 5.13.12. The failure comes from the Kbuild,
> > > which does not demote the missing trace point config option from error
> > > to warning. There is a patch file already in the layer, but it is only
> > > appended to the 'class-devupstream' and is missing in the SRC_URI.
> >
> > Hmmm. I ported the original patch, but yes, that Kbuild patch is also
> > needed (and it is my own patch no less).
> >
> > I was just updating the devupstream version yesterday, and ran across
> > that patch.
> >
> > None of the oe-core qemu* BSPs I test against have a disabled
> > tracepoint configuration, so I didn't run into that.
>
> I'd try to enable it locally on my end, just to see if LTTng would
> build with trace points enabled in the kernel config.

Just as a follow-up here: when FTRACE (and dependent config options)
is enabled in the kernel - LTTng builds happily. I guess your sanity
build went through with no issues exactly due to the fact that tracing
is enabled in Yocto kernels.

>
> >
> > I have the bumped devupstream version and the ported patch done
> > locally, I can send it out shortly, but it sounds like you've already
> > done that, so I can sit on that change.
>
> Please go ahead and send out your version, I'll be figuring out those
> build errors on my end, and it might take some time...
>
> >
> > >
> > > I was going to submit the patch to recipe to have it included, but
> > > testing the build stage with this patch included I'm seeing a lot of
> > > other errors then, something like:
> > >
> > > lttng-modules-2.13.0/src/lttng-tracepoint.c:227:36: error: 'struct
> > > module' has no member named 'num_tracepoints'
> > > -- or --
> > > src/probes/../../include/instrumentation/events/rpc.h:208:36: error:
> > > implicit declaration of function 'rpc_qname'
> > > [-Werror=implicit-function-declaration]
> > >
> > > and the list goes on... :/
> > >
> > > Have you seen this during testing of this new version? Any advise on
> > > where to look next?
> >
> > Not really. I end up updating lttng frequently, due to my constant
> > work on new kernel versions, but I'm not a lttng expert by any
> > definition.
>
> Same here, I just saw the build failure and started to poke around to
> see what could be the root cause of it.
>
> Missing KBuild patch was an easy find, but those compiler errors are not...
>
> >
> > The smoke tests passed when I ran the tests, I'll poke around a bit
> > and see if I can come up with any ideas (since clearly, our kernel
> > configurations are quite different, given that I never did run into
> > that patch not being in devupstream).
> >
> > Bruce
> >
> > >
> > > >
> > > > MODULES_MODULE_SYMVERS_LOCATION must also be specified in this
> > > > release, as the lttng build has moved the module target to a
> > > > 'src' subdirectory.
> > > >
> > > > Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
> > > > ---
> > > >  ...fail-if-CONFIG_TRACEPOINTS-is-not-en.patch | 32 ++++++-------------
> > > >  ...ules_2.12.6.bb => lttng-modules_2.13.0.bb} |  6 ++--
> > > >  2 files changed, 14 insertions(+), 24 deletions(-)
> > > >  rename meta/recipes-kernel/lttng/{lttng-modules_2.12.6.bb => lttng-modules_2.13.0.bb} (88%)
> > > >
> > > >
> > >
> > >
> > > --
> > > Regards,
> > > Andrey.
> >
> >
> >
> > --
> > - Thou shalt not follow the NULL pointer, for chaos and madness await
> > thee at its end
> > - "Use the force Harry" - Gandalf, Star Trek II
>
>
>
> --
> Regards,
> Andrey.



-- 
Regards,
Andrey.