From: anton <anton@openbsd.org>
Date: Tue, 21 Dec 2021 06:11:16 +0000 (+0000)
Subject: Ensure that the disk has been initialized after acquiring the lock and
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=4d2db379fd33b57e0ddb490faeb02b222092f374;p=openbsd

Ensure that the disk has been initialized after acquiring the lock and
not before as we might end up sleeping while acquiring the lock,
introducing a potential race.

Tested in snaps for a couple of days.

ok mpi@

Reported-by: syzbot+c87cdc2905b441c20d39@syzkaller.appspotmail.com
---

diff --git a/sys/dev/vnd.c b/sys/dev/vnd.c
index 9b7b2cec5ca..aee02516942 100644
--- a/sys/dev/vnd.c
+++ b/sys/dev/vnd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vnd.c,v 1.174 2021/11/21 23:07:11 deraadt Exp $	*/
+/*	$OpenBSD: vnd.c,v 1.175 2021/12/21 06:11:16 anton Exp $	*/
 /*	$NetBSD: vnd.c,v 1.26 1996/03/30 23:06:11 christos Exp $	*/
 
 /*
@@ -532,11 +532,12 @@ fail:
 		break;
 	    }
 	case VNDIOCCLR:
-		if ((sc->sc_flags & VNF_INITED) == 0)
-			return (ENXIO);
-
 		if ((error = disk_lock(&sc->sc_dk)) != 0)
 			return (error);
+		if ((sc->sc_flags & VNF_INITED) == 0) {
+			disk_unlock(&sc->sc_dk);
+			return (ENXIO);
+		}
 
 		/*
 		 * Don't unconfigure if any other partitions are open