[PATCH] bpfilter: check if $(CC) can static link in Kconfig

[PATCH] bpfilter: check if $(CC) can static link in Kconfig

[Masahiro Yamada]

On Fedora, linking static libraries requires the glibc-static RPM
package, which is not part of the glibc-devel package.

CONFIG_CC_CAN_LINK does not check the capability of static linking,
so you can enable CONFIG_BPFILTER_UMH, then fail to build.

  HOSTLD  net/bpfilter/bpfilter_umh
/usr/bin/ld: cannot find -lc
collect2: error: ld returned 1 exit status

Add CONFIG_CC_CAN_LINK_STATIC, and make CONFIG_BPFILTER_UMH depend
on it.

Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

I will insert this after
https://patchwork.kernel.org/patch/11515997/

 init/Kconfig         | 5 +++++
 net/bpfilter/Kconfig | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/init/Kconfig b/init/Kconfig
index 57562a8e2761..d0ff16e93794 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -49,6 +49,11 @@ config CC_CAN_LINK
 	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(m64-flag)) if 64BIT
 	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(m32-flag))
 
+config CC_CAN_LINK_STATIC
+	bool
+	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) -static $(m64-flag)) if 64BIT
+	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) -static $(m32-flag))
+
 config CC_HAS_ASM_GOTO
 	def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC))
 
diff --git a/net/bpfilter/Kconfig b/net/bpfilter/Kconfig
index fed9290e3b41..045144d4a42c 100644
--- a/net/bpfilter/Kconfig
+++ b/net/bpfilter/Kconfig
@@ -9,7 +9,7 @@ menuconfig BPFILTER
 if BPFILTER
 config BPFILTER_UMH
 	tristate "bpfilter kernel module with user mode helper"
-	depends on CC_CAN_LINK
+	depends on CC_CAN_LINK_STATIC
 	default m
 	help
 	  This builds bpfilter kernel module with embedded user mode helper
-- 
2.25.1

Re: [PATCH] bpfilter: check if $(CC) can static link in Kconfig

[Alexei Starovoitov]

On Sat, May 9, 2020 at 12:40 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> On Fedora, linking static libraries requires the glibc-static RPM
> package, which is not part of the glibc-devel package.
>
> CONFIG_CC_CAN_LINK does not check the capability of static linking,
> so you can enable CONFIG_BPFILTER_UMH, then fail to build.
>
>   HOSTLD  net/bpfilter/bpfilter_umh
> /usr/bin/ld: cannot find -lc
> collect2: error: ld returned 1 exit status
>
> Add CONFIG_CC_CAN_LINK_STATIC, and make CONFIG_BPFILTER_UMH depend
> on it.
>
> Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Thanks!
Acked-by: Alexei Starovoitov <ast@kernel.org>

Re: [PATCH] bpfilter: check if $(CC) can static link in Kconfig

[Masahiro Yamada]

On Sun, May 10, 2020 at 10:04 AM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Sat, May 9, 2020 at 12:40 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
> >
> > On Fedora, linking static libraries requires the glibc-static RPM
> > package, which is not part of the glibc-devel package.
> >
> > CONFIG_CC_CAN_LINK does not check the capability of static linking,
> > so you can enable CONFIG_BPFILTER_UMH, then fail to build.
> >
> >   HOSTLD  net/bpfilter/bpfilter_umh
> > /usr/bin/ld: cannot find -lc
> > collect2: error: ld returned 1 exit status
> >
> > Add CONFIG_CC_CAN_LINK_STATIC, and make CONFIG_BPFILTER_UMH depend
> > on it.
> >
> > Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
>
> Thanks!
> Acked-by: Alexei Starovoitov <ast@kernel.org>

Applied to linux-kbuild
with Alexei's Ack.


-- 
Best Regards
Masahiro Yamada