Re: [OE-core][PATCH v1] util-linux: backport pam_lastlog2 libpam linking fix

["Mathieu Dubois-Briand" <mathieu.dubois-briand@bootlin.com>]

On Thu Jun 25, 2026 at 11:02 AM CEST, Siva Balasubramanian via lists.openembedded.org wrote:
> pam_lastlog2.so uses pam_syslog() and other libpam symbols but the
> autotools build did not link the module against libpam. With the
> linker default of --as-needed, libpam was discarded and did not end
> up in the module's ELF NEEDED entries. The module then fails to load
> via dlopen() in processes that do not themselves link libpam (e.g.
> systemd on recent Fedora, or weston on journald-based systems without
> syslog):
>
>   PAM unable to dlopen(/usr/lib/security/pam_lastlog2.so): undefined symbol: pam_syslog
>   PAM adding faulty module: /usr/lib/security/pam_lastlog2.so
>
> Backport the upstream fix (in 2.41.5) that moves -lpam into LIBADD so
> it is placed after the object files and retained as a NEEDED entry.
> Against 2.41.3 only the LIBADD line needs changing.
>
> [YOCTO #16320]
>
> Signed-off-by: Siva Balasubramanian <sivakumar.bs@gmail.com>
> ---
> Verified by building util-linux with pam in DISTRO_FEATURES (qemux86-64):
> without the patch the resulting pam_lastlog2.so has no libpam in its ELF
> NEEDED entries; with the patch readelf -d reports libpam.so.0, matching
> the upstream fix and resolving the dlopen() failure from the bug report.
>
> This is also a candidate for the stable 6.0.x branch (per the bug
> report), which also ships util-linux 2.41.3; the same single-hunk
> backport applies.

Hi Siva,

Thanks for the patch.

We already have a pending patch for master, upgrading to 2.42.2 [1]. So
I believe this patch won't be needed for master. It probably still makes
sense for stable branches.

[1]: https://lore.kernel.org/openembedded-core/20260619083305.3505156-2-alex.kanavin@gmail.com/

Thanks,
Mathieu

-- 
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com