[PATCH 6.12.y] bpf: Fix BPF_INTERNAL namespace import

[PATCH 6.12.y] bpf: Fix BPF_INTERNAL namespace import

[Xi Ruoyao]

The commit cdd30ebb1b9f ("module: Convert symbol namespace to string
literal") makes the grammar of MODULE_IMPORT_NS and EXPORT_SYMBOL_NS
different between the stable branches and the mainline.  But when
the commit 955f9ede52b8 ("bpf: Add namespace to BPF internal symbols")
was backported from mainline, only EXPORT_SYMBOL_NS instances are
adapted, leaving the MODULE_IMPORT_NS instance with the "new" grammar
and causing the module fails to build:

    ERROR: modpost: module bpf_preload uses symbol bpf_link_get_from_fd from namespace BPF_INTERNAL, but does not import it.
    ERROR: modpost: module bpf_preload uses symbol kern_sys_bpf from namespace BPF_INTERNAL, but does not import it.

Reported-by: Mingcong Bai <jeffbai@aosc.io>
Reported-by: Alex Davis <alex47794@gmail.com>
Closes: https://lore.kernel.org/all/CADiockBKBQTVqjA5G+RJ9LBwnEnZ8o0odYnL=LBZ_7QN=_SZ7A@mail.gmail.com/
Fixes: 955f9ede52b8 ("bpf: Add namespace to BPF internal symbols")
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
---
 kernel/bpf/preload/bpf_preload_kern.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/preload/bpf_preload_kern.c b/kernel/bpf/preload/bpf_preload_kern.c
index 56a81df7a9d7..fdad0eb308fe 100644
--- a/kernel/bpf/preload/bpf_preload_kern.c
+++ b/kernel/bpf/preload/bpf_preload_kern.c
@@ -89,5 +89,5 @@ static void __exit fini(void)
 }
 late_initcall(load);
 module_exit(fini);
-MODULE_IMPORT_NS("BPF_INTERNAL");
+MODULE_IMPORT_NS(BPF_INTERNAL);
 MODULE_LICENSE("GPL");
-- 
2.49.0

Re: [PATCH 6.12.y] bpf: Fix BPF_INTERNAL namespace import

[Greg KH]

On Sat, May 03, 2025 at 04:50:31PM +0800, Xi Ruoyao wrote:
> The commit cdd30ebb1b9f ("module: Convert symbol namespace to string
> literal") makes the grammar of MODULE_IMPORT_NS and EXPORT_SYMBOL_NS
> different between the stable branches and the mainline.  But when
> the commit 955f9ede52b8 ("bpf: Add namespace to BPF internal symbols")
> was backported from mainline, only EXPORT_SYMBOL_NS instances are
> adapted, leaving the MODULE_IMPORT_NS instance with the "new" grammar
> and causing the module fails to build:
> 
>     ERROR: modpost: module bpf_preload uses symbol bpf_link_get_from_fd from namespace BPF_INTERNAL, but does not import it.
>     ERROR: modpost: module bpf_preload uses symbol kern_sys_bpf from namespace BPF_INTERNAL, but does not import it.
> 
> Reported-by: Mingcong Bai <jeffbai@aosc.io>
> Reported-by: Alex Davis <alex47794@gmail.com>
> Closes: https://lore.kernel.org/all/CADiockBKBQTVqjA5G+RJ9LBwnEnZ8o0odYnL=LBZ_7QN=_SZ7A@mail.gmail.com/
> Fixes: 955f9ede52b8 ("bpf: Add namespace to BPF internal symbols")
> Signed-off-by: Xi Ruoyao <xry111@xry111.site>
> ---
>  kernel/bpf/preload/bpf_preload_kern.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/bpf/preload/bpf_preload_kern.c b/kernel/bpf/preload/bpf_preload_kern.c
> index 56a81df7a9d7..fdad0eb308fe 100644
> --- a/kernel/bpf/preload/bpf_preload_kern.c
> +++ b/kernel/bpf/preload/bpf_preload_kern.c
> @@ -89,5 +89,5 @@ static void __exit fini(void)
>  }
>  late_initcall(load);
>  module_exit(fini);
> -MODULE_IMPORT_NS("BPF_INTERNAL");
> +MODULE_IMPORT_NS(BPF_INTERNAL);
>  MODULE_LICENSE("GPL");

Ick, sorry about that, I thought I had fixed this all up.  Odd it never
showed up in anyone's build testing, I wonder why.

I'll go do a quick release with just this fix in it now to get this
resolved, thanks!

greg k-h

Re: [PATCH 6.12.y] bpf: Fix BPF_INTERNAL namespace import

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

Summary of potential issues:
⚠️ Could not find matching upstream commit

No upstream commit was identified. Using temporary commit for testing.

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.12.y       |  Success    |  Success   |