[Buildroot] [PATCH 1/1] package/util-linux: fix non-MMU build

[Buildroot] [PATCH 1/1] package/util-linux: fix non-MMU build

[Bernd Kuhls]

Buildroot commit 31af509b4f4fe52f67bd9109b8732a55b8f9cd2d bumped the
package from 2.40.2 to 2.41.1. This bump includes upstream commit
https://github.com/util-linux/util-linux/commit/a3f1255f1891ddbaf3bb6a32af28569c0e6f3b91
which was added to version 2.41 and includes the usage of
pthread_atfork() causing build errors on non-MMU platforms:

libuuid/src/gen_uuid.c: In function 'uuid_generate_time_generic':
libuuid/src/gen_uuid.c:629:17: error: implicit declaration of function
 'pthread_atfork'; did you mean 'pthread_join'?
 [-Wimplicit-function-declaration]
  629 |                 pthread_atfork(NULL, NULL, reset_uuidd_cache);

The oldest build error of this kind can be found on the 2025.11.x
branch with version 2.41.1:
https://autobuild.buildroot.net/results/87c/87c74435be14956fd45f730269eac102e70d56da/

A backport of this patch to the LTS branches should be considered.

Fixes:
https://autobuild.buildroot.org/results/a21e81e64eccc866b575a4f3b1376c50f2ffd837/

Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
---
 package/util-linux/util-linux.mk | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/package/util-linux/util-linux.mk b/package/util-linux/util-linux.mk
index 1271bc7dc0..99a6be976e 100644
--- a/package/util-linux/util-linux.mk
+++ b/package/util-linux/util-linux.mk
@@ -130,6 +130,11 @@ UTIL_LINUX_CONF_ENV += CFLAGS="$(TARGET_CFLAGS) -Dstatic_assert=_Static_assert"
 UTIL_LINUX_CONF_ENV += LIBS="$(UTIL_LINUX_LINK_LIBS)"
 UTIL_LINUX_MAKE_OPTS += LIBS="$(UTIL_LINUX_LINK_LIBS)"
 
+# pthread support uses pthread_atfork, which is not available on nommu
+ifneq ($(BR2_USE_MMU),y)
+UTIL_LINUX_CONF_ENV += ac_cv_lib_pthread_pthread_atfork=no
+endif
+
 ifeq ($(BR2_PACKAGE_LIBSELINUX),y)
 UTIL_LINUX_DEPENDENCIES += libselinux
 UTIL_LINUX_CONF_OPTS += --with-selinux
-- 
2.47.3

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Re: [Buildroot] [PATCH 1/1] package/util-linux: fix non-MMU build

[Thomas Petazzoni via buildroot]

Hello Bernd,

On Sun, Apr 26, 2026 at 12:22:15PM +0200, Bernd Kuhls wrote:
> Buildroot commit 31af509b4f4fe52f67bd9109b8732a55b8f9cd2d bumped the
> package from 2.40.2 to 2.41.1. This bump includes upstream commit
> https://github.com/util-linux/util-linux/commit/a3f1255f1891ddbaf3bb6a32af28569c0e6f3b91
> which was added to version 2.41 and includes the usage of
> pthread_atfork() causing build errors on non-MMU platforms:
> 
> libuuid/src/gen_uuid.c: In function 'uuid_generate_time_generic':
> libuuid/src/gen_uuid.c:629:17: error: implicit declaration of function
>  'pthread_atfork'; did you mean 'pthread_join'?
>  [-Wimplicit-function-declaration]
>   629 |                 pthread_atfork(NULL, NULL, reset_uuidd_cache);
> 
> The oldest build error of this kind can be found on the 2025.11.x
> branch with version 2.41.1:
> https://autobuild.buildroot.net/results/87c/87c74435be14956fd45f730269eac102e70d56da/
> 
> A backport of this patch to the LTS branches should be considered.
> 
> Fixes:
> https://autobuild.buildroot.org/results/a21e81e64eccc866b575a4f3b1376c50f2ffd837/
> 
> Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
> ---
>  package/util-linux/util-linux.mk | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/package/util-linux/util-linux.mk b/package/util-linux/util-linux.mk
> index 1271bc7dc0..99a6be976e 100644
> --- a/package/util-linux/util-linux.mk
> +++ b/package/util-linux/util-linux.mk
> @@ -130,6 +130,11 @@ UTIL_LINUX_CONF_ENV += CFLAGS="$(TARGET_CFLAGS) -Dstatic_assert=_Static_assert"
>  UTIL_LINUX_CONF_ENV += LIBS="$(UTIL_LINUX_LINK_LIBS)"
>  UTIL_LINUX_MAKE_OPTS += LIBS="$(UTIL_LINUX_LINK_LIBS)"
>  
> +# pthread support uses pthread_atfork, which is not available on nommu
> +ifneq ($(BR2_USE_MMU),y)
> +UTIL_LINUX_CONF_ENV += ac_cv_lib_pthread_pthread_atfork=no
> +endif

Thanks for the patch and the detailed explanation. However, the
configure script has a check to see if pthread_atfork() is available
or not. Why is this configure check finding that pthread_atfork()
exists... and the build then fails because it doesn't exist?

Basically, your patch is papering over the real problem/question of
why the configure check is not working as it should.

I've started a build to have a look, but if you have some insights,
I'm interested.

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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