From 16598eeedf115523000b9a9b458333e59ef6538d Mon Sep 17 00:00:00 2001
From: ad <ad@NetBSD.org>
Date: Mon, 8 Oct 2007 18:09:37 +0000
Subject: [PATCH] Merge from vmlocking: don't hold scheduler locks across
 copyout().

---
 sys/kern/init_sysctl.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/sys/kern/init_sysctl.c b/sys/kern/init_sysctl.c
index c7410323bd77..6993619a8bd7 100644
--- a/sys/kern/init_sysctl.c
+++ b/sys/kern/init_sysctl.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: init_sysctl.c,v 1.106 2007/09/28 21:25:21 joerg Exp $ */
+/*	$NetBSD: init_sysctl.c,v 1.107 2007/10/08 18:09:37 ad Exp $ */
 
 /*-
  * Copyright (c) 2003 The NetBSD Foundation, Inc.
@@ -37,7 +37,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: init_sysctl.c,v 1.106 2007/09/28 21:25:21 joerg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: init_sysctl.c,v 1.107 2007/10/08 18:09:37 ad Exp $");
 
 #include "opt_sysv.h"
 #include "opt_multiprocessor.h"
@@ -1659,9 +1659,6 @@ sysctl_kern_lwp(SYSCTLFN_ARGS)
 				/*
 				 * Copy out elem_size, but not larger than
 				 * the size of a struct kinfo_proc2.
-				 *
-				 * XXX We should not be holding p_smutex, but
-				 * for now, the buffer is wired.  Fix later.
 				 */
 				error = dcopyout(l, &klwp, dp,
 				    min(sizeof(klwp), elem_size));
@@ -1682,21 +1679,31 @@ sysctl_kern_lwp(SYSCTLFN_ARGS)
 		mutex_enter(&p->p_smutex);	
 		LIST_FOREACH(l2, &p->p_lwps, l_sibling) {
 			if (buflen >= elem_size && elem_count > 0) {
+				struct lwp *l3;
+
 				lwp_lock(l2);
 				fill_lwp(l2, &klwp);
 				lwp_unlock(l2);
-
+				mutex_exit(&p->p_smutex);
 				/*
 				 * Copy out elem_size, but not larger than
 				 * the size of a struct kinfo_proc2.
-				 *
-				 * XXX We should not be holding p_smutex, but
-				 * for now, the buffer is wired.  Fix later.
 				 */
 				error = dcopyout(l, &klwp, dp,
 				    min(sizeof(klwp), elem_size));
-				if (error)
+				if (error) {
 					goto cleanup;
+				}
+				mutex_enter(&p->p_smutex);
+				LIST_FOREACH(l3, &p->p_lwps, l_sibling) {
+					if (l2 == l3)
+						break;
+				}
+				if (l2 == NULL) {
+					mutex_exit(&p->p_smutex);
+					error = EAGAIN;
+					goto cleanup;
+				}
 				dp += elem_size;
 				buflen -= elem_size;
 				elem_count--;
@@ -1717,6 +1724,7 @@ sysctl_kern_lwp(SYSCTLFN_ARGS)
 	}
 	return (0);
  cleanup:
+	mutex_exit(&proclist_lock);
 	return (error);
 }