From owner-p4-projects@FreeBSD.ORG  Thu May 10 15:28:23 2007
Return-Path: <owner-p4-projects@FreeBSD.ORG>
X-Original-To: p4-projects@freebsd.org
Delivered-To: p4-projects@freebsd.org
Received: by hub.freebsd.org (Postfix, from userid 32767)
	id A209216A406; Thu, 10 May 2007 15:28:23 +0000 (UTC)
X-Original-To: perforce@freebsd.org
Delivered-To: perforce@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id 3B62416A405
	for <perforce@freebsd.org>; Thu, 10 May 2007 15:28:23 +0000 (UTC)
	(envelope-from jhb@freebsd.org)
Received: from repoman.freebsd.org (repoman.freebsd.org [69.147.83.41])
	by mx1.freebsd.org (Postfix) with ESMTP id 2BEC713C455
	for <perforce@freebsd.org>; Thu, 10 May 2007 15:28:23 +0000 (UTC)
	(envelope-from jhb@freebsd.org)
Received: from repoman.freebsd.org (localhost [127.0.0.1])
	by repoman.freebsd.org (8.13.8/8.13.8) with ESMTP id l4AFSNgZ016565
	for <perforce@freebsd.org>; Thu, 10 May 2007 15:28:23 GMT
	(envelope-from jhb@freebsd.org)
Received: (from perforce@localhost)
	by repoman.freebsd.org (8.13.8/8.13.8/Submit) id l4AFSM8A016562
	for perforce@freebsd.org; Thu, 10 May 2007 15:28:23 GMT
	(envelope-from jhb@freebsd.org)
Date: Thu, 10 May 2007 15:28:23 GMT
Message-Id: <200705101528.l4AFSM8A016562@repoman.freebsd.org>
X-Authentication-Warning: repoman.freebsd.org: perforce set sender to
	jhb@freebsd.org using -f
From: John Baldwin <jhb@FreeBSD.org>
To: Perforce Change Reviews <perforce@freebsd.org>
Cc: 
Subject: PERFORCE change 119631 for review
X-BeenThere: p4-projects@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: p4 projects tree changes <p4-projects.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/p4-projects>,
	<mailto:p4-projects-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/p4-projects>
List-Post: <mailto:p4-projects@freebsd.org>
List-Help: <mailto:p4-projects-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/p4-projects>,
	<mailto:p4-projects-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 10 May 2007 15:28:24 -0000

http://perforce.freebsd.org/chv.cgi?CH=119631

Change 119631 by jhb@jhb_mutex on 2007/05/10 15:28:19

	Move cpu_exit() sooner.  There's no need to make this happen
	this late (most of them are nops, the others all deal with
	stuff that only affects userland).  Moving it allows us to avoid
	dropping the proc lock and parent proc lock after notifying other
	processes of our exit via kevent(2) or SIGCHLD but before setting
	PRS_ZOMBIE.  As a result, if the other process tried to do a
	waitpid(W_NOHANG) during that window, it wouldn't see the process
	as a zombie yet and would fail.

Affected files ...

.. //depot/projects/smpng/sys/kern/kern_exit.c#122 edit

Differences ...

==== //depot/projects/smpng/sys/kern/kern_exit.c#122 (text+ko) ====

@@ -406,6 +406,16 @@
 	sx_xunlock(&allproc_lock);
 
 	/*
+	 * Call machine-dependent code to release any
+	 * machine-dependent resources other than the address space.
+	 * The address space is released by "vmspace_exitfree(p)" in
+	 * vm_waitproc().
+	 */
+	cpu_exit(td);
+
+	WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid);
+
+	/*
 	 * Reparent all of our children to init.
 	 */
 	sx_xlock(&proctree_lock);
@@ -484,22 +494,6 @@
 		else	/* LINUX thread */
 			psignal(p->p_pptr, p->p_sigparent);
 	}
-	PROC_UNLOCK(p->p_pptr);
-	PROC_UNLOCK(p);
-
-	/*
-	 * Finally, call machine-dependent code to release the remaining
-	 * resources including address space.
-	 * The address space is released by "vmspace_exitfree(p)" in
-	 * vm_waitproc().
-	 */
-	cpu_exit(td);
-
-	WITNESS_WARN(WARN_PANIC, &proctree_lock.lock_object,
-	    "process (pid %d) exiting", p->p_pid);
-
-	PROC_LOCK(p);
-	PROC_LOCK(p->p_pptr);
 	sx_xunlock(&proctree_lock);
 
 	/*