PERFORCE change 90998 for review

[John Baldwin]

http://perforce.freebsd.org/chv.cgi?CH=90998

Change 90998 by jhb at jhb_slimer on 2006/02/03 21:34:55

	Block in exit1() until all holds on a process are released.

Affected files ...

.. //depot/projects/smpng/sys/kern/kern_exit.c#109 edit
.. //depot/projects/smpng/sys/sys/proc.h#161 edit

Differences ...

==== //depot/projects/smpng/sys/kern/kern_exit.c#109 (text+ko) ====

@@ -175,6 +175,13 @@
 
 	p->p_flag |= P_WEXIT;
 
+	/*
+	 * Wait for any processes that have a hold on our vmspace to
+	 * release their reference.
+	 */
+	while (p->p_lock > 0)
+		msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0);
+
 	PROC_LOCK(p->p_pptr);
 	sigqueue_take(p->p_ksi);
 	PROC_UNLOCK(p->p_pptr);

==== //depot/projects/smpng/sys/sys/proc.h#161 (text+ko) ====

@@ -785,6 +785,7 @@
 } while (0)
 #define	_PHOLD(p) do {							\
 	PROC_LOCK_ASSERT((p), MA_OWNED);				\
+	KASSERT(!((p)->p_flag & P_WEXIT), ("PHOLD of exiting process"));\
 	(p)->p_lock++;							\
 	if (((p)->p_sflag & PS_INMEM) == 0)				\
 		faultin((p));						\
@@ -798,6 +799,8 @@
 #define	_PRELE(p) do {							\
 	PROC_LOCK_ASSERT((p), MA_OWNED);				\
 	(--(p)->p_lock);						\
+	if (((p)->p_flag & P_WEXIT) && (p)->p_lock == 0)		\
+		wakeup(&(p)->p_lock);					\
 } while (0)
 
 /* Check whether a thread is safe to be swapped out. */