pam_setcred fails for "USE_POSIX_THREADS + non-root users + PrivSep yes"

[Kumaresh]

Hello,

We use USE_POSIX_THREADS in our HP-UX build of OpenSSH. When we connect a
non-root user with PAM [pam-kerberos] then I get the following error.

debug3: PAM: opening session
debug1: PAM: reinitializing credentials
PAM: pam_setcred(): Failure setting user credentials

This is particularly for non-root users with PrivSep YES. When I connect to
a root user with PrivSep YES or to a non-root user with PrivSep NO, then no
issues. This is tested on 3.7.1p2  and 3.8.1p1 and two versions behave
alike. This is not the case when USE_POSIX_THREADS is disabled and it works
for PrivSep yes and no for root and non-root users.

Just to check the pid that call the pam_setcred in do_pam_setcred, I used
the getpid() call in the do_pam_setcred function and for both THREAD enabled
and disabled builds, the child pid and the pid that call this function are
the same and inspite of this similarity this problem is seen.

Any help will be much appreciated.

Regards,
Kumar.