[PATCH bpf-next] bpf: Document the pahole release info related to libbpf in bpf_devel_QA.rst

[PATCH bpf-next] bpf: Document the pahole release info related to libbpf in bpf_devel_QA.rst

[Tiezhu Yang]

pahole starts to use libbpf definitions and APIs since v1.13 after the
commit 21507cd3e97b ("pahole: add libbpf as submodule under lib/bpf").
It works well with the git repository because the libbpf submodule will
use "git submodule update --init --recursive" to update.

Unfortunately, the default github release source code does not contain
libbpf submodule source code and this will cause build issues, the tarball
from https://git.kernel.org/pub/scm/devel/pahole/pahole.git/ is same with
github, you can get the source tarball with corresponding libbpf submodule
codes from

https://fedorapeople.org/~acme/dwarves

This change documents the above issues to give more information so that
we can get the tarball from the right place, early discussion is here:

https://lore.kernel.org/bpf/2de4aad5-fa9e-1c39-3c92-9bb9229d0966@loongson.cn/

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 Documentation/bpf/bpf_devel_QA.rst | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Documentation/bpf/bpf_devel_QA.rst b/Documentation/bpf/bpf_devel_QA.rst
index d05e67e..253496a 100644
--- a/Documentation/bpf/bpf_devel_QA.rst
+++ b/Documentation/bpf/bpf_devel_QA.rst
@@ -449,6 +449,19 @@ from source at
 
 https://github.com/acmel/dwarves
 
+pahole starts to use libbpf definitions and APIs since v1.13 after the
+commit 21507cd3e97b ("pahole: add libbpf as submodule under lib/bpf").
+It works well with the git repository because the libbpf submodule will
+use "git submodule update --init --recursive" to update.
+
+Unfortunately, the default github release source code does not contain
+libbpf submodule source code and this will cause build issues, the tarball
+from https://git.kernel.org/pub/scm/devel/pahole/pahole.git/ is same with
+github, you can get the source tarball with corresponding libbpf submodule
+codes from
+
+https://fedorapeople.org/~acme/dwarves
+
 Some distros have pahole version 1.16 packaged already, e.g.
 Fedora, Gentoo.
 
-- 
2.1.0

Re: [PATCH bpf-next] bpf: Document the pahole release info related to libbpf in bpf_devel_QA.rst

[Yonghong Song]

On 4/22/21 6:23 PM, Tiezhu Yang wrote:
> pahole starts to use libbpf definitions and APIs since v1.13 after the
> commit 21507cd3e97b ("pahole: add libbpf as submodule under lib/bpf").
> It works well with the git repository because the libbpf submodule will
> use "git submodule update --init --recursive" to update.
> 
> Unfortunately, the default github release source code does not contain
> libbpf submodule source code and this will cause build issues, the tarball
> from https://git.kernel.org/pub/scm/devel/pahole/pahole.git/ is same with
> github, you can get the source tarball with corresponding libbpf submodule
> codes from
> 
> https://fedorapeople.org/~acme/dwarves
> 
> This change documents the above issues to give more information so that
> we can get the tarball from the right place, early discussion is here:
> 
> https://lore.kernel.org/bpf/2de4aad5-fa9e-1c39-3c92-9bb9229d0966@loongson.cn/
> 
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
>   Documentation/bpf/bpf_devel_QA.rst | 13 +++++++++++++
>   1 file changed, 13 insertions(+)
> 
> diff --git a/Documentation/bpf/bpf_devel_QA.rst b/Documentation/bpf/bpf_devel_QA.rst
> index d05e67e..253496a 100644
> --- a/Documentation/bpf/bpf_devel_QA.rst
> +++ b/Documentation/bpf/bpf_devel_QA.rst
> @@ -449,6 +449,19 @@ from source at
>   
>   https://github.com/acmel/dwarves
>   
> +pahole starts to use libbpf definitions and APIs since v1.13 after the
> +commit 21507cd3e97b ("pahole: add libbpf as submodule under lib/bpf").
> +It works well with the git repository because the libbpf submodule will
> +use "git submodule update --init --recursive" to update.
> +
> +Unfortunately, the default github release source code does not contain
> +libbpf submodule source code and this will cause build issues, the tarball
> +from https://git.kernel.org/pub/scm/devel/pahole/pahole.git/ is same with
> +github, you can get the source tarball with corresponding libbpf submodule
> +codes from
> +
> +https://fedorapeople.org/~acme/dwarves
> +

Arnaldo, could you take a look at this patch? Thanks!

>   Some distros have pahole version 1.16 packaged already, e.g.
>   Fedora, Gentoo.
>   
> 

Re: [PATCH bpf-next] bpf: Document the pahole release info related to libbpf in bpf_devel_QA.rst

[Arnaldo Carvalho de Melo]

Em Thu, Apr 22, 2021 at 09:12:19PM -0700, Yonghong Song escreveu:
> 
> 
> On 4/22/21 6:23 PM, Tiezhu Yang wrote:
> > pahole starts to use libbpf definitions and APIs since v1.13 after the
> > commit 21507cd3e97b ("pahole: add libbpf as submodule under lib/bpf").
> > It works well with the git repository because the libbpf submodule will
> > use "git submodule update --init --recursive" to update.
> > 
> > Unfortunately, the default github release source code does not contain
> > libbpf submodule source code and this will cause build issues, the tarball
> > from https://git.kernel.org/pub/scm/devel/pahole/pahole.git/ is same with
> > github, you can get the source tarball with corresponding libbpf submodule
> > codes from
> > 
> > https://fedorapeople.org/~acme/dwarves
> > 
> > This change documents the above issues to give more information so that
> > we can get the tarball from the right place, early discussion is here:
> > 
> > https://lore.kernel.org/bpf/2de4aad5-fa9e-1c39-3c92-9bb9229d0966@loongson.cn/
> > 
> > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> > ---
> >   Documentation/bpf/bpf_devel_QA.rst | 13 +++++++++++++
> >   1 file changed, 13 insertions(+)
> > 
> > diff --git a/Documentation/bpf/bpf_devel_QA.rst b/Documentation/bpf/bpf_devel_QA.rst
> > index d05e67e..253496a 100644
> > --- a/Documentation/bpf/bpf_devel_QA.rst
> > +++ b/Documentation/bpf/bpf_devel_QA.rst
> > @@ -449,6 +449,19 @@ from source at
> >   https://github.com/acmel/dwarves
> > +pahole starts to use libbpf definitions and APIs since v1.13 after the
> > +commit 21507cd3e97b ("pahole: add libbpf as submodule under lib/bpf").
> > +It works well with the git repository because the libbpf submodule will
> > +use "git submodule update --init --recursive" to update.
> > +
> > +Unfortunately, the default github release source code does not contain
> > +libbpf submodule source code and this will cause build issues, the tarball
> > +from https://git.kernel.org/pub/scm/devel/pahole/pahole.git/ is same with
> > +github, you can get the source tarball with corresponding libbpf submodule
> > +codes from
> > +
> > +https://fedorapeople.org/~acme/dwarves
> > +
> 
> Arnaldo, could you take a look at this patch? Thanks!

Sure, he documented it as I expected from a previous interaction about
this. Would be good to add a paragraph stating how to grab libbpf and
graft it even on a tarball not containing it tho.

Bonus points if the cmake files gets changed in a way that this gets
notified to the user in the error message.

But these suggestions can come in another patch, for this I can give my:

Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>

- Arnaldo
 
> >   Some distros have pahole version 1.16 packaged already, e.g.
> >   Fedora, Gentoo.

Re: [PATCH bpf-next] bpf: Document the pahole release info related to libbpf in bpf_devel_QA.rst

[Alexei Starovoitov]

On Fri, Apr 23, 2021 at 11:20 AM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> Em Thu, Apr 22, 2021 at 09:12:19PM -0700, Yonghong Song escreveu:
> >
> >
> > On 4/22/21 6:23 PM, Tiezhu Yang wrote:
> > > pahole starts to use libbpf definitions and APIs since v1.13 after the
> > > commit 21507cd3e97b ("pahole: add libbpf as submodule under lib/bpf").
> > > It works well with the git repository because the libbpf submodule will
> > > use "git submodule update --init --recursive" to update.
> > >
> > > Unfortunately, the default github release source code does not contain
> > > libbpf submodule source code and this will cause build issues, the tarball
> > > from https://git.kernel.org/pub/scm/devel/pahole/pahole.git/ is same with
> > > github, you can get the source tarball with corresponding libbpf submodule
> > > codes from
> > >
> > > https://fedorapeople.org/~acme/dwarves
> > >
> > > This change documents the above issues to give more information so that
> > > we can get the tarball from the right place, early discussion is here:
> > >
> > > https://lore.kernel.org/bpf/2de4aad5-fa9e-1c39-3c92-9bb9229d0966@loongson.cn/
> > >
> > > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> > > ---
> > >   Documentation/bpf/bpf_devel_QA.rst | 13 +++++++++++++
> > >   1 file changed, 13 insertions(+)
> > >
> > > diff --git a/Documentation/bpf/bpf_devel_QA.rst b/Documentation/bpf/bpf_devel_QA.rst
> > > index d05e67e..253496a 100644
> > > --- a/Documentation/bpf/bpf_devel_QA.rst
> > > +++ b/Documentation/bpf/bpf_devel_QA.rst
> > > @@ -449,6 +449,19 @@ from source at
> > >   https://github.com/acmel/dwarves
> > > +pahole starts to use libbpf definitions and APIs since v1.13 after the
> > > +commit 21507cd3e97b ("pahole: add libbpf as submodule under lib/bpf").
> > > +It works well with the git repository because the libbpf submodule will
> > > +use "git submodule update --init --recursive" to update.
> > > +
> > > +Unfortunately, the default github release source code does not contain
> > > +libbpf submodule source code and this will cause build issues, the tarball
> > > +from https://git.kernel.org/pub/scm/devel/pahole/pahole.git/ is same with
> > > +github, you can get the source tarball with corresponding libbpf submodule
> > > +codes from
> > > +
> > > +https://fedorapeople.org/~acme/dwarves
> > > +
> >
> > Arnaldo, could you take a look at this patch? Thanks!
>
> Sure, he documented it as I expected from a previous interaction about
> this. Would be good to add a paragraph stating how to grab libbpf and
> graft it even on a tarball not containing it tho.
>
> Bonus points if the cmake files gets changed in a way that this gets
> notified to the user in the error message.
>
> But these suggestions can come in another patch, for this I can give my:
>
> Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Applied. Thanks everyone.