[src/trunk]: src/sys/dev/audio Add missing mutex, we were hitting a KASSERT.

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

details:   https://anonhg.NetBSD.org/src/rev/ed28e9984184
branches:  trunk
changeset: 459090:ed28e9984184
user:      maxv <maxv%NetBSD.org@localhost>
date:      Fri Aug 23 09:41:26 2019 +0000

description:
Add missing mutex, we were hitting a KASSERT.

diffstat:

 sys/dev/audio/audio.c |  6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diffs (28 lines):

diff -r eb08cebfb498 -r ed28e9984184 sys/dev/audio/audio.c
--- a/sys/dev/audio/audio.c     Fri Aug 23 08:45:25 2019 +0000
+++ b/sys/dev/audio/audio.c     Fri Aug 23 09:41:26 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: audio.c,v 1.28 2019/07/10 13:26:47 isaki Exp $ */
+/*     $NetBSD: audio.c,v 1.29 2019/08/23 09:41:26 maxv Exp $  */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -142,7 +142,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.28 2019/07/10 13:26:47 isaki Exp $");
+__KERNEL_RCSID(0, "$NetBSD: audio.c,v 1.29 2019/08/23 09:41:26 maxv Exp $");
 
 #ifdef _KERNEL_OPT
 #include "audio.h"
@@ -7726,7 +7726,9 @@
                } else {
                        ma = NULL;
                }
+               mutex_enter(sc->sc_lock);
                mixer_remove(sc);       /* remove old entry */
+               mutex_exit(sc->sc_lock);
                if (ma != NULL) {
                        ma->next = sc->sc_async_mixer;
                        ma->pid = curproc->p_pid;