[PATCH] kbuild: disable DEBUG_INFO_SPLIT when BTF is on

[PATCH] kbuild: disable DEBUG_INFO_SPLIT when BTF is on

[Slava Bacherikov]

Currently turning on DEBUG_INFO_SPLIT when DEBUG_INFO_BTF is also
enabled will produce invalid btf file, since gen_btf function in
link-vmlinux.sh script doesn't handle *.dwo files.

Signed-off-by: Slava Bacherikov <slava@bacher09.org>
---
 lib/Kconfig.debug | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index f61d834e02fe..a9429ef5eec8 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -223,6 +223,7 @@ config DEBUG_INFO_DWARF4
 config DEBUG_INFO_BTF
 	bool "Generate BTF typeinfo"
 	depends on DEBUG_INFO
+	depends on !DEBUG_INFO_SPLIT
 	help
 	  Generate deduplicated BTF type information from DWARF debug info.
 	  Turning this on expects presence of pahole tool, which will convert
-- 
2.24.1

Re: [PATCH] kbuild: disable DEBUG_INFO_SPLIT when BTF is on

[Andrii Nakryiko]

On Tue, Mar 31, 2020 at 9:57 AM Slava Bacherikov <slava@bacher09.org> wrote:
>
> Currently turning on DEBUG_INFO_SPLIT when DEBUG_INFO_BTF is also
> enabled will produce invalid btf file, since gen_btf function in
> link-vmlinux.sh script doesn't handle *.dwo files.
>
> Signed-off-by: Slava Bacherikov <slava@bacher09.org>
> ---
>  lib/Kconfig.debug | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index f61d834e02fe..a9429ef5eec8 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -223,6 +223,7 @@ config DEBUG_INFO_DWARF4
>  config DEBUG_INFO_BTF
>         bool "Generate BTF typeinfo"
>         depends on DEBUG_INFO
> +       depends on !DEBUG_INFO_SPLIT

Thanks for following up! This looks good, but I think there are more
DWARF-related configs that should be banned. See [0] and [1]. If you
don't mind, let's use your patch to disable all of them in one go. So
can you please update and disable DEBUG_INFO_REDUCED and
GCC_PLUGIN_RANDSTRUCT? Thanks!

  [0] https://lore.kernel.org/bpf/202003311110.2B08091E@keescook
  [1] https://lore.kernel.org/bpf/a2b1a025-6a70-c3a5-fc19-155f0266946a@fb.com


>         help
>           Generate deduplicated BTF type information from DWARF debug info.
>           Turning this on expects presence of pahole tool, which will convert
> --
> 2.24.1
>

Re: [PATCH] kbuild: disable DEBUG_INFO_SPLIT when BTF is on

[Andrii Nakryiko]

On Tue, Mar 31, 2020 at 12:45 PM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Tue, Mar 31, 2020 at 9:57 AM Slava Bacherikov <slava@bacher09.org> wrote:
> >
> > Currently turning on DEBUG_INFO_SPLIT when DEBUG_INFO_BTF is also
> > enabled will produce invalid btf file, since gen_btf function in
> > link-vmlinux.sh script doesn't handle *.dwo files.
> >
> > Signed-off-by: Slava Bacherikov <slava@bacher09.org>
> > ---
> >  lib/Kconfig.debug | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> > index f61d834e02fe..a9429ef5eec8 100644
> > --- a/lib/Kconfig.debug
> > +++ b/lib/Kconfig.debug
> > @@ -223,6 +223,7 @@ config DEBUG_INFO_DWARF4
> >  config DEBUG_INFO_BTF
> >         bool "Generate BTF typeinfo"
> >         depends on DEBUG_INFO
> > +       depends on !DEBUG_INFO_SPLIT
>
> Thanks for following up! This looks good, but I think there are more
> DWARF-related configs that should be banned. See [0] and [1]. If you
> don't mind, let's use your patch to disable all of them in one go. So
> can you please update and disable DEBUG_INFO_REDUCED and
> GCC_PLUGIN_RANDSTRUCT? Thanks!
>
>   [0] https://lore.kernel.org/bpf/202003311110.2B08091E@keescook
>   [1] https://lore.kernel.org/bpf/a2b1a025-6a70-c3a5-fc19-155f0266946a@fb.com
>

I guess at this point it should go against bpf tree, so please update
header to [PATCH v2 bpf]. Please also add Reported-by and Fixes tag:

Reported-by: Jann Horn <jannh@google.com>
Reported-by: Liu Yiding <liuyd.fnst@cn.fujitsu.com>
Fixes: e83b9f55448a ("kbuild: add ability to generate BTF type info
for vmlinux")

Thanks!

>
> >         help
> >           Generate deduplicated BTF type information from DWARF debug info.
> >           Turning this on expects presence of pahole tool, which will convert
> > --
> > 2.24.1
> >