[src/trunk]: src/sys/dev Avoid NULL deref in case no bufq has been set.

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

details:   https://anonhg.NetBSD.org/src/rev/e3fa28fd49c9
branches:  trunk
changeset: 816253:e3fa28fd49c9
user:      mlelstv <mlelstv%NetBSD.org@localhost>
date:      Sun Jun 26 07:22:15 2016 +0000

description:
Avoid NULL deref in case no bufq has been set.

diffstat:

 sys/dev/dksubr.c |  15 +++++++--------
 1 files changed, 7 insertions(+), 8 deletions(-)

diffs (45 lines):

diff -r 22fe077d5798 -r e3fa28fd49c9 sys/dev/dksubr.c
--- a/sys/dev/dksubr.c  Sun Jun 26 07:10:24 2016 +0000
+++ b/sys/dev/dksubr.c  Sun Jun 26 07:22:15 2016 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: dksubr.c,v 1.86 2016/01/04 10:02:15 mlelstv Exp $ */
+/* $NetBSD: dksubr.c,v 1.87 2016/06/26 07:22:15 mlelstv Exp $ */
 
 /*-
  * Copyright (c) 1996, 1997, 1998, 1999, 2002, 2008 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: dksubr.c,v 1.86 2016/01/04 10:02:15 mlelstv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dksubr.c,v 1.87 2016/06/26 07:22:15 mlelstv Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -658,12 +658,13 @@
                struct disk_strategy *dks = (void *)data;
 
                mutex_enter(&dksc->sc_iolock);
-               strlcpy(dks->dks_name, bufq_getstrategyname(dksc->sc_bufq),
-                   sizeof(dks->dks_name));
+               if (dksc->sc_bufq != NULL)
+                       strlcpy(dks->dks_name, bufq_getstrategyname(dksc->sc_bufq),
+                           sizeof(dks->dks_name));
+               else
+                       error = EINVAL;
                mutex_exit(&dksc->sc_iolock);
                dks->dks_paramlen = 0;
-
-               return 0;
            }
 
        case DIOCSSTRATEGY:
@@ -687,8 +688,6 @@
                dksc->sc_bufq = new;
                mutex_exit(&dksc->sc_iolock);
                bufq_free(old);
-
-               return 0;
            }
 
        default: