Does the implementation of pthread rwlock obey POSIX specification?

[Neil]

Hi All,

I am testing POSIX on project Yocto with POSIX suite from ltp site:
http://ltp.git.sourceforge.net/git/gitweb.cgi?p=ltp/ltp.git;a=tree;f=testcases/open_posix_testsuite;h=2ef1a9c3eca086d06f3ed2061c32c610c44a78da;hb=HEAD

When run the test test case
open_posix_testsuite/conformance/interfaces/pthread_rwlock_rdlock/2-1.c
http://ltp.git.sourceforge.net/git/gitweb.cgi?p=ltp/ltp.git;a=blob_plain;f=testcashttp://ltp.git.sourceforge.net/git/gitweb.cgi?p=ltp/ltp.git;a=blob_plain;f=testcases/open_posix_testsuite/conformance/interfaces/pthread_rwlock_rdlock/2-1.c;hb=HEADes/open_posix_testsuite/conformance/interfaces/pthread_rwlock_rdlock/2-1.c;hb=HEAD
it fails. Test steps are as follow:

1.  Main thread set its shcedule policy as "SCHED_FIFO", with highest
priority: sched_get_priority_min()+2.
2.  Main thread read lock 'rwlock'
3.  Create a writer thread, with schedule policy as "SCHED_FIFO", and
priority using sched_get_priority_min()+1.
4.  The thread write lock 'rwlock', should block.
5.  Main thread create a reader thread, with schedule policy as
"SCHED_FIFO", and priority sched_get_priority_min()
6.  Reader thread read lock 'rwlock', should block, since there is a
higher priority  writer blocked on 'rwlock'

But the reader thread doesn't block. Because in  POSIX specification
or pthread_rwlock_rdlock() manual page says:

       If  the  Thread  Execution Scheduling option is supported, and
the threads involved in the lock are executing
       with the scheduling policies SCHED_FIFO or SCHED_RR, the
calling thread shall  not  acquire  the  lock  if  a
       writer holds the lock or if writers of higher or equal priority
are blocked on the lock; otherwise, the call‐
       ing thread shall acquire the lock.

So it seems the implementation of pthread rwlock doesn't obey the
POSIX specification, right? If so, if there is a plan to
make eglibc  rwlock obey the POSIX specification?
I notice that there is a flag in pthread_rwlock_t to spec prefer read
lock or right lock, but it doesn't care the priorities.

Any reply is appreciate.

--
Regards,
Neil