[src/trunk]: src/sys/kern sysctl_kern_proc_args: fix the deadlock (hi joerg!).

[rmind <rmind%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/85145188b53b
branches:  trunk
changeset: 763843:85145188b53b
user:      rmind <rmind%NetBSD.org@localhost>
date:      Tue Apr 05 09:02:23 2011 +0000

description:
sysctl_kern_proc_args: fix the deadlock (hi joerg!).

diffstat:

 sys/kern/kern_proc.c |  9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diffs (31 lines):

diff -r 6cdf6e3fe1fc -r 85145188b53b sys/kern/kern_proc.c
--- a/sys/kern/kern_proc.c      Tue Apr 05 08:51:05 2011 +0000
+++ b/sys/kern/kern_proc.c      Tue Apr 05 09:02:23 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_proc.c,v 1.173 2011/03/05 01:52:18 matt Exp $     */
+/*     $NetBSD: kern_proc.c,v 1.174 2011/04/05 09:02:23 rmind Exp $    */
 
 /*-
  * Copyright (c) 1999, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -62,7 +62,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_proc.c,v 1.173 2011/03/05 01:52:18 matt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_proc.c,v 1.174 2011/04/05 09:02:23 rmind Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_kstack.h"
@@ -1940,8 +1940,11 @@
                goto out_locked;
        }
 
-       rw_enter(&p->p_reflock, RW_READER);
+       error = rw_tryenter(&p->p_reflock, RW_READER) ? 0 : EBUSY;
        mutex_exit(p->p_lock);
+       if (error) {
+               goto out_locked;
+       }
        mutex_exit(proc_lock);
 
        if (type == KERN_PROC_NARGV || type == KERN_PROC_NENV) {