[v3] scripts: Exclude Rust CUs with pahole

Message ID 20230111152050.559334-1-yakoyoku@gmail.com
State New
Headers
Series [v3] scripts: Exclude Rust CUs with pahole |

Commit Message

Martin Rodriguez Reboredo Jan. 11, 2023, 3:20 p.m. UTC
  Version 1.24 of pahole has the capability to exclude compilation units
(CUs) of specific languages [1] [2]. Rust, as of writing, is not
currently supported by pahole and if it's used with a build that has
BTF debugging enabled it results in malformed kernel and module
binaries [3]. So it's better for pahole to exclude Rust CUs until
support for it arrives.

Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=49358dfe2aaae4e90b072332c3e324019826783f [1]
Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=8ee363790b7437283c53090a85a9fec2f0b0fbc4 [2]
Link: https://github.com/Rust-for-Linux/linux/issues/735 [3]

Co-developed-by: Eric Curtin <ecurtin@redhat.com>
Signed-off-by: Eric Curtin <ecurtin@redhat.com>
Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
---
V2 -> V3: Enable pahole option upon comparing with version 1.24
V1 -> V2: Removed dependency on auto.conf

 init/Kconfig            | 2 +-
 lib/Kconfig.debug       | 9 +++++++++
 scripts/pahole-flags.sh | 4 ++++
 3 files changed, 14 insertions(+), 1 deletion(-)
  

Comments

Eric Curtin Jan. 11, 2023, 3:22 p.m. UTC | #1
On Wed, 11 Jan 2023 at 15:21, Martin Rodriguez Reboredo
<yakoyoku@gmail.com> wrote:
>
> Version 1.24 of pahole has the capability to exclude compilation units
> (CUs) of specific languages [1] [2]. Rust, as of writing, is not
> currently supported by pahole and if it's used with a build that has
> BTF debugging enabled it results in malformed kernel and module
> binaries [3]. So it's better for pahole to exclude Rust CUs until
> support for it arrives.
>
> Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=49358dfe2aaae4e90b072332c3e324019826783f [1]
> Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=8ee363790b7437283c53090a85a9fec2f0b0fbc4 [2]
> Link: https://github.com/Rust-for-Linux/linux/issues/735 [3]
>
> Co-developed-by: Eric Curtin <ecurtin@redhat.com>
> Signed-off-by: Eric Curtin <ecurtin@redhat.com>
> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>

I think this should be able to cover all the quirky build techniques.

Tested-by: Eric Curtin <ecurtin@redhat.com>

> ---
> V2 -> V3: Enable pahole option upon comparing with version 1.24
> V1 -> V2: Removed dependency on auto.conf
>
>  init/Kconfig            | 2 +-
>  lib/Kconfig.debug       | 9 +++++++++
>  scripts/pahole-flags.sh | 4 ++++
>  3 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/init/Kconfig b/init/Kconfig
> index 694f7c160c9c..360aef8d7292 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -1913,7 +1913,7 @@ config RUST
>         depends on !MODVERSIONS
>         depends on !GCC_PLUGINS
>         depends on !RANDSTRUCT
> -       depends on !DEBUG_INFO_BTF
> +       depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
>         select CONSTRUCTORS
>         help
>           Enables Rust support in the kernel.
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index ea4c903c9868..d473d491e709 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -364,6 +364,15 @@ config PAHOLE_HAS_BTF_TAG
>           btf_decl_tag) or not. Currently only clang compiler implements
>           these attributes, so make the config depend on CC_IS_CLANG.
>
> +config PAHOLE_HAS_LANG_EXCLUDE
> +       def_bool PAHOLE_VERSION >= 124
> +       help
> +         Support for the --lang_exclude flag which makes pahole exclude
> +         compilation units from the supplied language. Used in Kbuild to
> +         omit Rust CUs which are not supported in version 1.24 of pahole,
> +         otherwise it would emit malformed kernel and module binaries when
> +         using DEBUG_INFO_BTF_MODULES.
> +
>  config DEBUG_INFO_BTF_MODULES
>         def_bool y
>         depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
> diff --git a/scripts/pahole-flags.sh b/scripts/pahole-flags.sh
> index 0d99ef17e4a5..1f1f1d397c39 100755
> --- a/scripts/pahole-flags.sh
> +++ b/scripts/pahole-flags.sh
> @@ -19,5 +19,9 @@ fi
>  if [ "${pahole_ver}" -ge "122" ]; then
>         extra_paholeopt="${extra_paholeopt} -j"
>  fi
> +if [ "${pahole_ver}" -ge "124" ]; then
> +       # see PAHOLE_HAS_LANG_EXCLUDE
> +       extra_paholeopt="${extra_paholeopt} --lang_exclude=rust"
> +fi
>
>  echo ${extra_paholeopt}
> --
> 2.39.0
>
  
Neal Gompa Jan. 11, 2023, 3:34 p.m. UTC | #2
On Wed, Jan 11, 2023 at 10:21 AM Martin Rodriguez Reboredo
<yakoyoku@gmail.com> wrote:
>
> Version 1.24 of pahole has the capability to exclude compilation units
> (CUs) of specific languages [1] [2]. Rust, as of writing, is not
> currently supported by pahole and if it's used with a build that has
> BTF debugging enabled it results in malformed kernel and module
> binaries [3]. So it's better for pahole to exclude Rust CUs until
> support for it arrives.
>
> Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=49358dfe2aaae4e90b072332c3e324019826783f [1]
> Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=8ee363790b7437283c53090a85a9fec2f0b0fbc4 [2]
> Link: https://github.com/Rust-for-Linux/linux/issues/735 [3]
>
> Co-developed-by: Eric Curtin <ecurtin@redhat.com>
> Signed-off-by: Eric Curtin <ecurtin@redhat.com>
> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
> ---
> V2 -> V3: Enable pahole option upon comparing with version 1.24
> V1 -> V2: Removed dependency on auto.conf
>
>  init/Kconfig            | 2 +-
>  lib/Kconfig.debug       | 9 +++++++++
>  scripts/pahole-flags.sh | 4 ++++
>  3 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/init/Kconfig b/init/Kconfig
> index 694f7c160c9c..360aef8d7292 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -1913,7 +1913,7 @@ config RUST
>         depends on !MODVERSIONS
>         depends on !GCC_PLUGINS
>         depends on !RANDSTRUCT
> -       depends on !DEBUG_INFO_BTF
> +       depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE

Does the order matter here? I'd rather it prefer a fixed pahole and
disable BTF only if we can't use pahole properly.


>         select CONSTRUCTORS
>         help
>           Enables Rust support in the kernel.
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index ea4c903c9868..d473d491e709 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -364,6 +364,15 @@ config PAHOLE_HAS_BTF_TAG
>           btf_decl_tag) or not. Currently only clang compiler implements
>           these attributes, so make the config depend on CC_IS_CLANG.
>
> +config PAHOLE_HAS_LANG_EXCLUDE
> +       def_bool PAHOLE_VERSION >= 124
> +       help
> +         Support for the --lang_exclude flag which makes pahole exclude
> +         compilation units from the supplied language. Used in Kbuild to
> +         omit Rust CUs which are not supported in version 1.24 of pahole,
> +         otherwise it would emit malformed kernel and module binaries when
> +         using DEBUG_INFO_BTF_MODULES.
> +
>  config DEBUG_INFO_BTF_MODULES
>         def_bool y
>         depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
> diff --git a/scripts/pahole-flags.sh b/scripts/pahole-flags.sh
> index 0d99ef17e4a5..1f1f1d397c39 100755
> --- a/scripts/pahole-flags.sh
> +++ b/scripts/pahole-flags.sh
> @@ -19,5 +19,9 @@ fi
>  if [ "${pahole_ver}" -ge "122" ]; then
>         extra_paholeopt="${extra_paholeopt} -j"
>  fi
> +if [ "${pahole_ver}" -ge "124" ]; then
> +       # see PAHOLE_HAS_LANG_EXCLUDE
> +       extra_paholeopt="${extra_paholeopt} --lang_exclude=rust"
> +fi
>
>  echo ${extra_paholeopt}
> --
> 2.39.0
>


--
真実はいつも一つ!/ Always, there's only one truth!
  
Eric Curtin Jan. 11, 2023, 4:16 p.m. UTC | #3
On Wed, 11 Jan 2023 at 15:34, Neal Gompa <neal@gompa.dev> wrote:
>
> On Wed, Jan 11, 2023 at 10:21 AM Martin Rodriguez Reboredo
> <yakoyoku@gmail.com> wrote:
> >
> > Version 1.24 of pahole has the capability to exclude compilation units
> > (CUs) of specific languages [1] [2]. Rust, as of writing, is not
> > currently supported by pahole and if it's used with a build that has
> > BTF debugging enabled it results in malformed kernel and module
> > binaries [3]. So it's better for pahole to exclude Rust CUs until
> > support for it arrives.
> >
> > Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=49358dfe2aaae4e90b072332c3e324019826783f [1]
> > Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=8ee363790b7437283c53090a85a9fec2f0b0fbc4 [2]
> > Link: https://github.com/Rust-for-Linux/linux/issues/735 [3]
> >
> > Co-developed-by: Eric Curtin <ecurtin@redhat.com>
> > Signed-off-by: Eric Curtin <ecurtin@redhat.com>
> > Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
> > ---
> > V2 -> V3: Enable pahole option upon comparing with version 1.24
> > V1 -> V2: Removed dependency on auto.conf
> >
> >  init/Kconfig            | 2 +-
> >  lib/Kconfig.debug       | 9 +++++++++
> >  scripts/pahole-flags.sh | 4 ++++
> >  3 files changed, 14 insertions(+), 1 deletion(-)
> >
> > diff --git a/init/Kconfig b/init/Kconfig
> > index 694f7c160c9c..360aef8d7292 100644
> > --- a/init/Kconfig
> > +++ b/init/Kconfig
> > @@ -1913,7 +1913,7 @@ config RUST
> >         depends on !MODVERSIONS
> >         depends on !GCC_PLUGINS
> >         depends on !RANDSTRUCT
> > -       depends on !DEBUG_INFO_BTF
> > +       depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
>
> Does the order matter here? I'd rather it prefer a fixed pahole and
> disable BTF only if we can't use pahole properly.

The order won't matter.

>
>
> >         select CONSTRUCTORS
> >         help
> >           Enables Rust support in the kernel.
> > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> > index ea4c903c9868..d473d491e709 100644
> > --- a/lib/Kconfig.debug
> > +++ b/lib/Kconfig.debug
> > @@ -364,6 +364,15 @@ config PAHOLE_HAS_BTF_TAG
> >           btf_decl_tag) or not. Currently only clang compiler implements
> >           these attributes, so make the config depend on CC_IS_CLANG.
> >
> > +config PAHOLE_HAS_LANG_EXCLUDE
> > +       def_bool PAHOLE_VERSION >= 124
> > +       help
> > +         Support for the --lang_exclude flag which makes pahole exclude
> > +         compilation units from the supplied language. Used in Kbuild to
> > +         omit Rust CUs which are not supported in version 1.24 of pahole,
> > +         otherwise it would emit malformed kernel and module binaries when
> > +         using DEBUG_INFO_BTF_MODULES.
> > +
> >  config DEBUG_INFO_BTF_MODULES
> >         def_bool y
> >         depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
> > diff --git a/scripts/pahole-flags.sh b/scripts/pahole-flags.sh
> > index 0d99ef17e4a5..1f1f1d397c39 100755
> > --- a/scripts/pahole-flags.sh
> > +++ b/scripts/pahole-flags.sh
> > @@ -19,5 +19,9 @@ fi
> >  if [ "${pahole_ver}" -ge "122" ]; then
> >         extra_paholeopt="${extra_paholeopt} -j"
> >  fi
> > +if [ "${pahole_ver}" -ge "124" ]; then
> > +       # see PAHOLE_HAS_LANG_EXCLUDE
> > +       extra_paholeopt="${extra_paholeopt} --lang_exclude=rust"
> > +fi
> >
> >  echo ${extra_paholeopt}
> > --
> > 2.39.0
> >
>
>
> --
> 真実はいつも一つ!/ Always, there's only one truth!
>
  
Neal Gompa Jan. 11, 2023, 4:21 p.m. UTC | #4
On Wed, Jan 11, 2023 at 11:16 AM Eric Curtin <ecurtin@redhat.com> wrote:
>
> On Wed, 11 Jan 2023 at 15:34, Neal Gompa <neal@gompa.dev> wrote:
> >
> > On Wed, Jan 11, 2023 at 10:21 AM Martin Rodriguez Reboredo
> > <yakoyoku@gmail.com> wrote:
> > >
> > > Version 1.24 of pahole has the capability to exclude compilation units
> > > (CUs) of specific languages [1] [2]. Rust, as of writing, is not
> > > currently supported by pahole and if it's used with a build that has
> > > BTF debugging enabled it results in malformed kernel and module
> > > binaries [3]. So it's better for pahole to exclude Rust CUs until
> > > support for it arrives.
> > >
> > > Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=49358dfe2aaae4e90b072332c3e324019826783f [1]
> > > Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=8ee363790b7437283c53090a85a9fec2f0b0fbc4 [2]
> > > Link: https://github.com/Rust-for-Linux/linux/issues/735 [3]
> > >
> > > Co-developed-by: Eric Curtin <ecurtin@redhat.com>
> > > Signed-off-by: Eric Curtin <ecurtin@redhat.com>
> > > Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
> > > ---
> > > V2 -> V3: Enable pahole option upon comparing with version 1.24
> > > V1 -> V2: Removed dependency on auto.conf
> > >
> > >  init/Kconfig            | 2 +-
> > >  lib/Kconfig.debug       | 9 +++++++++
> > >  scripts/pahole-flags.sh | 4 ++++
> > >  3 files changed, 14 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/init/Kconfig b/init/Kconfig
> > > index 694f7c160c9c..360aef8d7292 100644
> > > --- a/init/Kconfig
> > > +++ b/init/Kconfig
> > > @@ -1913,7 +1913,7 @@ config RUST
> > >         depends on !MODVERSIONS
> > >         depends on !GCC_PLUGINS
> > >         depends on !RANDSTRUCT
> > > -       depends on !DEBUG_INFO_BTF
> > > +       depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
> >
> > Does the order matter here? I'd rather it prefer a fixed pahole and
> > disable BTF only if we can't use pahole properly.
>
> The order won't matter.
>

Then it looks good to me!

Reviewed-by: Neal Gompa <neal@gompa.dev>
  
Daniel Borkmann Jan. 16, 2023, 4:37 p.m. UTC | #5
On 1/11/23 4:20 PM, Martin Rodriguez Reboredo wrote:
> Version 1.24 of pahole has the capability to exclude compilation units
> (CUs) of specific languages [1] [2]. Rust, as of writing, is not
> currently supported by pahole and if it's used with a build that has
> BTF debugging enabled it results in malformed kernel and module
> binaries [3]. So it's better for pahole to exclude Rust CUs until
> support for it arrives.
> 
> Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=49358dfe2aaae4e90b072332c3e324019826783f [1]
> Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=8ee363790b7437283c53090a85a9fec2f0b0fbc4 [2]
> Link: https://github.com/Rust-for-Linux/linux/issues/735 [3]
> 
> Co-developed-by: Eric Curtin <ecurtin@redhat.com>
> Signed-off-by: Eric Curtin <ecurtin@redhat.com>
> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
> ---
> V2 -> V3: Enable pahole option upon comparing with version 1.24
> V1 -> V2: Removed dependency on auto.conf
> 
>   init/Kconfig            | 2 +-
>   lib/Kconfig.debug       | 9 +++++++++
>   scripts/pahole-flags.sh | 4 ++++
>   3 files changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/init/Kconfig b/init/Kconfig
> index 694f7c160c9c..360aef8d7292 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -1913,7 +1913,7 @@ config RUST
>   	depends on !MODVERSIONS
>   	depends on !GCC_PLUGINS
>   	depends on !RANDSTRUCT
> -	depends on !DEBUG_INFO_BTF
> +	depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
>   	select CONSTRUCTORS
>   	help
>   	  Enables Rust support in the kernel.
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index ea4c903c9868..d473d491e709 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -364,6 +364,15 @@ config PAHOLE_HAS_BTF_TAG
>   	  btf_decl_tag) or not. Currently only clang compiler implements
>   	  these attributes, so make the config depend on CC_IS_CLANG.
>   
> +config PAHOLE_HAS_LANG_EXCLUDE
> +	def_bool PAHOLE_VERSION >= 124
> +	help
> +	  Support for the --lang_exclude flag which makes pahole exclude
> +	  compilation units from the supplied language. Used in Kbuild to
> +	  omit Rust CUs which are not supported in version 1.24 of pahole,
> +	  otherwise it would emit malformed kernel and module binaries when
> +	  using DEBUG_INFO_BTF_MODULES.
> +
>   config DEBUG_INFO_BTF_MODULES
>   	def_bool y
>   	depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
> diff --git a/scripts/pahole-flags.sh b/scripts/pahole-flags.sh
> index 0d99ef17e4a5..1f1f1d397c39 100755
> --- a/scripts/pahole-flags.sh
> +++ b/scripts/pahole-flags.sh
> @@ -19,5 +19,9 @@ fi
>   if [ "${pahole_ver}" -ge "122" ]; then
>   	extra_paholeopt="${extra_paholeopt} -j"
>   fi
> +if [ "${pahole_ver}" -ge "124" ]; then
> +	# see PAHOLE_HAS_LANG_EXCLUDE
> +	extra_paholeopt="${extra_paholeopt} --lang_exclude=rust"
> +fi
>   
>   echo ${extra_paholeopt}

I presume Miguel will pick this up via rust tree? (Either way, would be nice to
also get an Ack from Arnaldo.)

Thanks,
Daniel
  
Miguel Ojeda Jan. 16, 2023, 4:52 p.m. UTC | #6
On Mon, Jan 16, 2023 at 5:37 PM Daniel Borkmann <daniel@iogearbox.net> wrote:
>
> I presume Miguel will pick this up via rust tree? (Either way, would be nice to
> also get an Ack from Arnaldo.)

I am happy to, but I think it would be great if BPF takes it whenever
you think it is a good time. And indeed, let's give time to Arnaldo to
take a look.

Cheers,
Miguel
  
Daniel Borkmann Jan. 16, 2023, 5:06 p.m. UTC | #7
On 1/16/23 5:52 PM, Miguel Ojeda wrote:
> On Mon, Jan 16, 2023 at 5:37 PM Daniel Borkmann <daniel@iogearbox.net> wrote:
>>
>> I presume Miguel will pick this up via rust tree? (Either way, would be nice to
>> also get an Ack from Arnaldo.)
> 
> I am happy to, but I think it would be great if BPF takes it whenever
> you think it is a good time. And indeed, let's give time to Arnaldo to
> take a look.

Ok, if you could ack it for the rust bits, we can route it via bpf-next.

Thanks,
Daniel
  
Miguel Ojeda Jan. 16, 2023, 5:19 p.m. UTC | #8
On Mon, Jan 16, 2023 at 6:06 PM Daniel Borkmann <daniel@iogearbox.net> wrote:
>
> Ok, if you could ack it for the rust bits, we can route it via bpf-next.

Of course:

Acked-by: Miguel Ojeda <ojeda@kernel.org>

Cheers,
Miguel
  
Arnaldo Carvalho de Melo Jan. 16, 2023, 7:22 p.m. UTC | #9
Em Mon, Jan 16, 2023 at 05:37:08PM +0100, Daniel Borkmann escreveu:
> On 1/11/23 4:20 PM, Martin Rodriguez Reboredo wrote:
> > Version 1.24 of pahole has the capability to exclude compilation units
> > (CUs) of specific languages [1] [2]. Rust, as of writing, is not
> > currently supported by pahole and if it's used with a build that has
> > BTF debugging enabled it results in malformed kernel and module
> > binaries [3]. So it's better for pahole to exclude Rust CUs until
> > support for it arrives.
> > 
> > Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=49358dfe2aaae4e90b072332c3e324019826783f [1]
> > Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=8ee363790b7437283c53090a85a9fec2f0b0fbc4 [2]
> > Link: https://github.com/Rust-for-Linux/linux/issues/735 [3]
> > 
> > Co-developed-by: Eric Curtin <ecurtin@redhat.com>
> > Signed-off-by: Eric Curtin <ecurtin@redhat.com>
> > Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
> > ---
> > V2 -> V3: Enable pahole option upon comparing with version 1.24
> > V1 -> V2: Removed dependency on auto.conf
> > 
> >   init/Kconfig            | 2 +-
> >   lib/Kconfig.debug       | 9 +++++++++
> >   scripts/pahole-flags.sh | 4 ++++
> >   3 files changed, 14 insertions(+), 1 deletion(-)
> > 
> > diff --git a/init/Kconfig b/init/Kconfig
> > index 694f7c160c9c..360aef8d7292 100644
> > --- a/init/Kconfig
> > +++ b/init/Kconfig
> > @@ -1913,7 +1913,7 @@ config RUST
> >   	depends on !MODVERSIONS
> >   	depends on !GCC_PLUGINS
> >   	depends on !RANDSTRUCT
> > -	depends on !DEBUG_INFO_BTF
> > +	depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
> >   	select CONSTRUCTORS
> >   	help
> >   	  Enables Rust support in the kernel.
> > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> > index ea4c903c9868..d473d491e709 100644
> > --- a/lib/Kconfig.debug
> > +++ b/lib/Kconfig.debug
> > @@ -364,6 +364,15 @@ config PAHOLE_HAS_BTF_TAG
> >   	  btf_decl_tag) or not. Currently only clang compiler implements
> >   	  these attributes, so make the config depend on CC_IS_CLANG.
> > +config PAHOLE_HAS_LANG_EXCLUDE
> > +	def_bool PAHOLE_VERSION >= 124
> > +	help
> > +	  Support for the --lang_exclude flag which makes pahole exclude
> > +	  compilation units from the supplied language. Used in Kbuild to
> > +	  omit Rust CUs which are not supported in version 1.24 of pahole,
> > +	  otherwise it would emit malformed kernel and module binaries when
> > +	  using DEBUG_INFO_BTF_MODULES.
> > +
> >   config DEBUG_INFO_BTF_MODULES
> >   	def_bool y
> >   	depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
> > diff --git a/scripts/pahole-flags.sh b/scripts/pahole-flags.sh
> > index 0d99ef17e4a5..1f1f1d397c39 100755
> > --- a/scripts/pahole-flags.sh
> > +++ b/scripts/pahole-flags.sh
> > @@ -19,5 +19,9 @@ fi
> >   if [ "${pahole_ver}" -ge "122" ]; then
> >   	extra_paholeopt="${extra_paholeopt} -j"
> >   fi
> > +if [ "${pahole_ver}" -ge "124" ]; then
> > +	# see PAHOLE_HAS_LANG_EXCLUDE
> > +	extra_paholeopt="${extra_paholeopt} --lang_exclude=rust"
> > +fi
> >   echo ${extra_paholeopt}
> 
> I presume Miguel will pick this up via rust tree? (Either way, would be nice to
> also get an Ack from Arnaldo.)

I haven't had the time to actually go and test it from top to bottom
(which I'm about to do), but it _looks_ ok, so:

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

- Arnaldo
  
patchwork-bot+netdevbpf@kernel.org Jan. 17, 2023, 4:40 p.m. UTC | #10
Hello:

This patch was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <daniel@iogearbox.net>:

On Wed, 11 Jan 2023 12:20:50 -0300 you wrote:
> Version 1.24 of pahole has the capability to exclude compilation units
> (CUs) of specific languages [1] [2]. Rust, as of writing, is not
> currently supported by pahole and if it's used with a build that has
> BTF debugging enabled it results in malformed kernel and module
> binaries [3]. So it's better for pahole to exclude Rust CUs until
> support for it arrives.
> 
> [...]

Here is the summary with links:
  - [v3] scripts: Exclude Rust CUs with pahole
    https://git.kernel.org/bpf/bpf-next/c/c1177979af9c

You are awesome, thank you!
  

Patch

diff --git a/init/Kconfig b/init/Kconfig
index 694f7c160c9c..360aef8d7292 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1913,7 +1913,7 @@  config RUST
 	depends on !MODVERSIONS
 	depends on !GCC_PLUGINS
 	depends on !RANDSTRUCT
-	depends on !DEBUG_INFO_BTF
+	depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
 	select CONSTRUCTORS
 	help
 	  Enables Rust support in the kernel.
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index ea4c903c9868..d473d491e709 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -364,6 +364,15 @@  config PAHOLE_HAS_BTF_TAG
 	  btf_decl_tag) or not. Currently only clang compiler implements
 	  these attributes, so make the config depend on CC_IS_CLANG.
 
+config PAHOLE_HAS_LANG_EXCLUDE
+	def_bool PAHOLE_VERSION >= 124
+	help
+	  Support for the --lang_exclude flag which makes pahole exclude
+	  compilation units from the supplied language. Used in Kbuild to
+	  omit Rust CUs which are not supported in version 1.24 of pahole,
+	  otherwise it would emit malformed kernel and module binaries when
+	  using DEBUG_INFO_BTF_MODULES.
+
 config DEBUG_INFO_BTF_MODULES
 	def_bool y
 	depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
diff --git a/scripts/pahole-flags.sh b/scripts/pahole-flags.sh
index 0d99ef17e4a5..1f1f1d397c39 100755
--- a/scripts/pahole-flags.sh
+++ b/scripts/pahole-flags.sh
@@ -19,5 +19,9 @@  fi
 if [ "${pahole_ver}" -ge "122" ]; then
 	extra_paholeopt="${extra_paholeopt} -j"
 fi
+if [ "${pahole_ver}" -ge "124" ]; then
+	# see PAHOLE_HAS_LANG_EXCLUDE
+	extra_paholeopt="${extra_paholeopt} --lang_exclude=rust"
+fi
 
 echo ${extra_paholeopt}