Re: [COMMITTED PATCH] Test that pthread_create diagnoses invalid scheduling parameters.

[Roland McGrath <roland at hack dot frob dot com>]

Fixed thusly.  This does change things slightly from the status quo ante,
but I suspect the old state was not what we really intended to be doing.
Previously, ATTR_FLAG_{POLICY,SCHED}_SET would not be set in PD->flags at
creation time when IATTR->flags had the bit set (and so PD->schedfoo has
value copied from IATTR->schedfoo) but *would* be set when IATTR->flags had
the bit clear (and so PD->schedfoo has a value gleaned via the sched_getfoo
syscall on the pthread_create caller).  Logically that seems backwards at
best.  Practically, I think the only effect is whether
pthread_getschedparam, __pthread_tpp_change_priority, and
__pthread_current_priority yield values already cached in the calling
thread's struct pthread or refresh that cache by making syscalls (so there
is no effect on the second or later repeated call to one of those).  Per
the comment in pthread_getschedparam, no kosher program could notice the
difference.  I think the status quo ante was just an oversight.


Thanks,
Roland


2014-11-21  Roland McGrath  <roland@hack.frob.com>

	* nptl/pthread_create.c (__pthread_create_2_1): Set
	ATTR_FLAG_POLICY_SET and/or ATTR_FLAG_SCHED_SET in PD->flags
	when copying values from IATTR into PD.

--- a/nptl/pthread_create.c
+++ b/nptl/pthread_create.c
@@ -596,10 +596,16 @@ __pthread_create_2_1 (newthread, attr, start_routine, arg)
     {
       /* Use the scheduling parameters the user provided.  */
       if (iattr->flags & ATTR_FLAG_POLICY_SET)
-	pd->schedpolicy = iattr->schedpolicy;
+        {
+          pd->schedpolicy = iattr->schedpolicy;
+          pd->flags |= ATTR_FLAG_POLICY_SET;
+        }
       if (iattr->flags & ATTR_FLAG_SCHED_SET)
-        /* The values were validated in pthread_attr_setschedparam.  */
-        pd->schedparam = iattr->schedparam;
+        {
+          /* The values were validated in pthread_attr_setschedparam.  */
+          pd->schedparam = iattr->schedparam;
+          pd->flags |= ATTR_FLAG_SCHED_SET;
+        }
 
       if ((pd->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET))
           != (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET))