From bb9ca91194363731e3daf811eb010cbcbdda2c3f Mon Sep 17 00:00:00 2001
From: jh <jh@FreeBSD.org>
Date: Sun, 12 Dec 2010 08:52:13 +0000
Subject: [PATCH] Handle the special ruleset 0 in devfs_ruleset_use(). An
 attempt set the current ruleset to 0 with command "devfs ruleset 0" triggered
 a KASSERT in devfs_ruleset_create().

PR:		kern/125030
Submitted by:	Mateusz Guzik
---
 sys/fs/devfs/devfs_rule.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sys/fs/devfs/devfs_rule.c b/sys/fs/devfs/devfs_rule.c
index 3d01f454c874..d3a3ef36dac1 100644
--- a/sys/fs/devfs/devfs_rule.c
+++ b/sys/fs/devfs/devfs_rule.c
@@ -742,6 +742,11 @@ devfs_ruleset_use(devfs_rsnum rsnum, struct devfs_mount *dm)
 		devfs_ruleset_reap(cds);
 	}
 
+	if (rsnum == 0) {
+		dm->dm_ruleset = 0;
+		return (0);
+	}
+
 	ds = devfs_ruleset_bynum(rsnum);
 	if (ds == NULL)
 		ds = devfs_ruleset_create(rsnum);